Hyperlipid

FIRKO mice

2012-01-23T21:04:00.005Z

Okay. I have an apology to make. I'm not sure there will be an MCQ test on the FIRKO mouse to parallel that on the LIRKO mouse. At this stage of the proceedings I'm not sure that I can muster the motivation which is needed to do justice to such an Herculean task of applied sarcasm. The difficulty is compounded by the loss of my trowel somewhere between Berkshire and Norfolk via Glasgow. You really do need a trowel. I know, excuses, excuses. Mea culpa.

With that apology, I think it's time to discuss this paper.

So now we have the FIRKO mouse. This mutant mouse has been cleverly engineered to fail to express insulin receptors on its adipocytes. Everything else is normal. Functionally the adipocytes are severely insulin resistant. It does not matter how much insulin the pancreas secretes, adipocytes will not, cannot, listen to it. You know the rules. The function of insulin is to store dietary fat in adipocytes. In the almost complete absence of any insulin receptors on any adipocytes, this just ain't gonna happen. So FIRKO mice stay slim, slightly slimmer than a control mouse, and live a bit longer. All on CIAB and without cutting calories of course.

They also fail to develop age related insulin resistance. Please note as a complete aside; those mice on F9, boring old low fat CIAB, do develop age related insulin resistance and glucose intolerance. Wanna stay as healthy as a mouse on F9 with age acquired insulin resistance? Go ahead and eat low fat, about 10% of your calories will do. Try not to get too bored.

I could stop here with this comment from the authors:

"Our data further show that insulin signalling in adipocytes is crucial for triglyceride storage and the development of obesity and its associated metabolic abnormalities"

It would be fun to just thumb your data at those fixated on the central effects of insulin but that would be leaving a whole can of worms unopened. You know how it ticks you off to get partial information on a given study. The selective information rationing typical an obesity researcher. The data are actually quite complex.

Let's get a tin opener.

Sooooooo, what if you take a FIRKO mouse and inject it with gold thioglucose? Obviously you will bust its VMH. You could equally use a electrical ice-pick or a big meal at a Chinese restaurant (jk).

To summarise the last post: This injury increases the ability of adipocytes to divert calories away from metabolism and in to storage, by an increase in their sensitivity to insulin. Fat should simply pour in to the adipocytes of a VMH injured rodent and they should start eating big time. You could be forgiven for thinking you had removed their brain satiety centre or upped their fat set-point.

But the FIRKO mouse has very few insulin receptors on its adipocytes. The brain can scream, shout and have a temper tantrum to demand fat storage. Adipocytes stay cool as a cucumber and don't even give the finger to the brain. Pure ignore-ance. The brain has lost its tool for fat storage. You know the one, the tool which stops you being hungry (snigger) and helps you lose weight (sigh). Insulin.

Now let's look at some of the graphs. We'll start with the supportive one:

We can ignore the middle two columns, they're from different knockout mice. FIRKO mice with a gold thioglucose brain injury (right hand column) weigh the same as, or even a non significant smidge less than, WT mice (or FIRKO mice) without a gold thioglucose injury. Now that's no surprise. Brain:Adipocyte:Insulin.

But there is a shock in store. Here's the next graph, the columns are the same:

FIRKO mice eat MORE if they are injured by gold thioglucose than if they aren't. They eat almost exactly the same extra food as a wild type gold thioglucose injured mouse. While staying slim, of course. But they do eat more.

Does this mean that the VMH really controls appetite rather than the ability to divert calories to fat storage?

FIRKO mice have markedly reduced insulin receptors on both white and brown adipose tissue. The consequence of this on white adipose tissue is simple, insulin causes fat storage, lack of receptors limits fat storage. BAT is more complex. We do have a BATIRKO mouse which has had the insulin receptors knocked out on its brown adipose tissue only. This leads to combined atrophy of BAT (the normal lipid droplets in BAT never form) with marked up regulation of UCP1 production. They stay slim compared to controls while being fed CIAB (aside: although slim they do eventually become diabetic, the reasons for which are utterly unclear to anyone, see the discussion). As the authors comment on "normal" BATIRKO mice:

"Interestingly, the lack of IR leads to the over expression of the UCP-1 and also UCP-2 in the remnant BAT from BATIRKO as compared with controls. These data could be interpreted as a form of compensatory mechanism for the brown fat lipid content and mass loss observed in BATIRKO and may result in a potential increase in the thermogenic capacity of the remnant BAT that may account for the lean phenotype of BATIRKO mice compared with controls"

A lack of insulin receptors on your BAT up regulates thermogenesis. This has nothing to do with the brain and everything to do with the periphery. Why should thermogenesis be increased by VMH injury? I don't know. The control of BAT is complex and I don't think the work has been done yet. There are hints that insulin reduces UCP1 production in mice, bringing us back to changes in insulin signalling and thermogenesis. You might expect a system which activates fat storage might turn off fat burning and vice versa.

At the moment, for FIRKO mice, it looks like an open question as to whether gold thioglucose VMH lesions really increase appetite directly or increases thermogenesis in BAT causing a calorie loss, with compensatory hyperphagia. You can imagine which option I think may be the case, but I do have certain biases.

It's frustrating that there is no information to follow through on this. The group's last publication on the FIRKO mouse was in 2007 and was interesting in its own right.

The FIRKO mouse has white adipose tissue which, with age, gets to have better and better mitochondria. Probably more of them too. The authors talk about increased whole body oxidative metabolism but don't seem to consider BAT seperately from WAT... But having your adipocytes live in [what to them is] an hypoinsulinaemic environment seems to be rather good for them. And the mouse

Anyway, summary:

Remember what is special about FIRKO mouse is that its adipocytes never see insulin, whatever the blood insulin level. Lacking IRs on all of your adipocytes keeps you slim, keeps your insulin levels low and extends your life expectancy by about 18%. It gives you shiny new mitochondria in your adipocytes as you age. If you are a mouse.

It it possible to mimic this state in non-FIRKO mice?

Perhaps it's time to revisit ketogenic diets in mice. Oh, and cirrhosis too.

Peter

Used brain for sale: One careful owner, only slightly broken

2012-01-17T20:43:00.007Z

Let's start with the old Stranglers track, "No More Heros", take an ice pick to a rat's brain and make its ears burn. OK, chew up its ventromedial hypothalamus with an electrolysis needle. This French paper is a pdf.

Here's the interesting table from the results:

At week one, when weight gain has started but not gone very far, fasting insulin was unchanged but blood glucose was LOWER than that of control rats. These rats, with their brain injury, have increased whole body insulin sensitivity. Mostly prominently in their adipocytes. The paper mentions in the discussion that these rats also hyper secrete insulin in response to secretagogues. Now, as we all know, insulin is both anorexic and unimportant to weight control. But if you just imagined, as I do, for a second that insulin does have something to do with weight gain, what would you expect to happen if you dropped hyper-secreted insulin on to exquisitely insulin sensitive adipocytes? Their job is to store fat under the influence of insulin so...

They would store fat. They would hang on to it. As Taubes might comment, the rats then over-eat because they are losing calories in to their adipocytes. They over eat because they are becoming fat. How do you check this? Well, let's pair feed ice-picked rats with control rats. Limit their calories. Make them go to uncheatable Weight Watchers in a prison cage. From the discussion:

"However pair-feeding rats with controls does not prevent excessive lipogenesis, fat accumulation and hyperinsulinemia [48, 49], suggesting that the disturbances of metabolism and not hyperphagia are the primary factors leading to obesity."

You injure the brain, alter the adipocytes and they store fat. Hyperphagia is an epiphenomenon of calories lost to adipocytes. They store fat even WITHOUT hyperphagia. This was quite obvious in 1992.

Enough frivolity. Let's get slightly more up to date with some Spanish MSG rats.

You have to be a bit careful with MSG injured rats. MSG is a potent neurotoxin and kills or injures almost any cell sporting glutamate receptors. This includes large numbers of nerve cells in the VMH, the target of the electrical ice-pick. However it also blunts growth hormone production, shuts down thermogenesis from brown adipose tissue and, very interestingly, adipocytes themselves probably use glutamic acid for cross talk purposes, so it's hard to know exactly what we do to MSG treated rats in addition to busting their VMH. You have to wonder whether the adipocytes themselves are injured by MSG.

Anyway, at a month of age, MSG injured rats have highly insulin sensitive adipocytes. Before the rats have become visibly obese their fat cells are already somewhat swollen and ready for the off in to full blown blobby-ness, come puberty. So again, you bust the VMH, increase adipocyte insulin sensitivity, adipocytes suck in fat and your rat simply has to eat to maintain access to enough energy to stay alive and cart the inaccessible fat around its cage. It probably doesn't dream of going to the gym.

If adipocytes are hypersensitive to insulin, what would you expect fasting FFAs, glucose and insulin look like before obesity developed?

Eyeball the HOMA score! These rats are a picture of glucoregulatory health! Unfortunately you need an energy supply from somewhere and some extra FFAs might just sort that out. You really need to develop some adipocyte distension induced insulin resistance by becoming obese to get the FFAs up to an appropriate level for a fasting rat. That's just what they do...

Look at the numbers from some Slovakian MSG injured rats as adults.

Cool, huh? Unfortunately we don't have the FFA level in the paper but, looking at the adipocyte size, they will be leaking FFAs in defiance of their double-the-control-rat level of insulin.

Now, are these adult, distended adipocytes insulin sensitive or resistant?

Well, they do bugger all to increase glucose uptake with increasing insulin exposure. So yes, they are insulin resistant. But look at this:

What glucose they do take up is diverted to fat. Might we say they are behaving like muscle cells which lack metabolic flexibility? Mitochondrial injury?

So, as obesity becomes established we end up in the age old situation of insulin resistant distended adipocytes leading to more FFA leakage than appropriate for a given level of insulin and so hyperinsulinaemia develops to try to keep blood glucose normal in the face of chronically elevated FFAs. This is absolutely not the case in the very early days, but rapidly becomes so with time.

This is all quite straight forwards and nothing you wouldn't expect if you accept the importance of insulin in obesity, adipocyte hypertrophy induced insulin resistance and the fact that adipocytes have a nerve supply which regulates their insulin sensitivity. In fact there are interesting papers on the role of adrenal hormones and the vagus as well as the sympathetic nervous system in MSG injury induced obesity. The end result is always increased insulin sensitivity of adipocytes until they become over-distended.

You can, of course, do exactly the same with gold thioglucose. Getting bored with all this? I'd basically come to the conclusion that VMH injuries give the impression of causing hyperphagia when what they actually do is increase lipid loss in to adipocytes, under the influence of insulin.

Okaaaay.

Let's look at a Long-Evans rat. If you feed it on D12492, which has been described as a high fat diet, for just three days, its brain breaks.

What if it is the fat that breaks the brain?

Well, my brain is then going to be completely f*cked.

I really do think that it might just be the fat that does it. How do I know? God told me. Okay, okay, only kidding. About god.

No, James emailed me a link to the latest Schwartz offering. I suspect that Dr Schwartz does not like Gary Taubes. We can also skip to the blog of the 4th author, who certainly does not like Gary Taubes, load up on ondansetron and have a browse. The blog says:

"Based on previous studies, the dietary fat itself is probably an important component that makes D12492 fattening in rodents"

The man is correct.

If you have quite recovered from that, let's look at the simpler aspects of the study. We can come back to the superb electron micrographs of dying mitochondria some other time. BTW, they are very, very cool pictures. I've been looking for similar photomicrographs all over the place. Who would have thought I would have found them here? Anyhoo:

First off, let's look at Figure 1, skip to graph H.

Start some ratties on D12492 and they will immediately double their calorie intake, on day 1. After living your whole short life eating CIAB I can understand this. D12492 tastes so good you just can't help yourself and it must be quite easy to eat enough of it to break your brain. It must be very rewarding. Luckily your brain recovers a bit and soon, by day seven, you're not eating any more calories of D12492 than a rat on CIAB and that's how it stays for the full 28 day period. We can tell this from Graph G. Here the average 28d food consumption on D12492 is only just above the 14d average consumed as CIAB. This excess is mostly accounted for by the first seven days of hyperphagia.

The bit of the brain which breaks "in association" with the massive 60% of calories from fat is the good old VMH. If we go back to the ice-pick rats, the MSG rats and the gold thioglucose rats we might just develop the suspicion that breaking the brain of a Long-Evans rat might affect the insulin sensitivity of its adipocytes.

If it does, fat from the diet will simply pour in to the adipose tissue and the unfortunate rattie will then have to eat extra to supply some energy to run its metabolism on in addition to that used for filling its adipocytes. Initially twice the amount it ate on CIAB. As the adipocytes fill they will become intrinsically less sensitive to insulin and fat accumulation, with its necessary compensatory hyperphagia, will slow. But not stop, if they behave anything like adipocytes in other VMH injured rat models.

On a high fat diet there is plenty of fat to pour in to adipocytes, no lipogenesis is needed. Adipocytes can distend quickly and it would be interesting to see if the fasting hypoinsulinaemia seen in the MSG rats (fed on high carbohydrate CIAB) occurs in D12492 injured rats. Probably it would still occur but be very transient, but obviously no one in the Schwartz lab would be interested in insulin.

Of course, one has to wonder which component of the D12492 might injure a rat's VMH. We are all familiar with the conversation (scroll up to get to the text) between Chris Masterjohn and the good doctor, where the omega 6 PUFA content of D12492 was noted to be 32% of fat and the omega 6:3 ratio was 14 or 16:1. All fascinating background. But my favourite obesity researcher correctly thinks it is the fat, not the type of fat, which breaks the VMH.

You can do exactly the same with butter oil (plus a smidge of soybean oil), which I'm guessing is a bit like ghee. Which I rather like. This is what butter oil at 20g/100g of food does to a Long-Evans rat in this study:

In particular look at what happened to the group HF. They switched from non purified (NP) diet on day 1 on the graph, spiked their intake to about 50% extra calories by day 5ish and were almost back down to the NP group's caloric intake by day 10. Exactly the same pattern as the D12492 also produces in Long-Evans rats.

It is impossible to emphasise how important both studies are to you if you are a Long-Evans rat.

Does three days of high fat eating break your brain if you are a human being? I have to admit that I appear to have singularly failed to become obese on 80% of my calories as fat over nine years. Possibly because 80% of your calories from fat becomes protective? I dunno. I can't help but recall those chaps in Aberdeen eating 66% of their calories as fat and refusing to finish off their allotted 2000kcal/d...

I have to be open to the idea that humans may not respond to high fat feeding in quite the same way as Long-Evans rats do. OK, they just don't. Their VMH doesn't acutely break. The rat is in trouble on 60% of calories as any sort of fat. Humans just say "no thank you" to the extra slice of bacon, in Aberdeen anyway. Oh, and in Lowestoft too.

In summary: Injuring your VMH in any way (even by eating butter oil if you are a Long-Evans rat) does nasty things to your adipocytes. They will store fat even if you cut calories. You will then be very hungry and, unless you do eat more, you will chew up your muscles for energy, get cold and move as little as possible. Oh, and still get fat. People will say you lie about your calorie intake.

Now, is it possible to become obese without breaking your VMH? Of course it is. Does it matter? That depends.

I think the chronic changes in both the Long-Evans rats and the C57BL/6 mice are very important and are quite likely different from the initial fat induced injury to the VMH. They appear to be more related to the chronic hyperinsulinaemia and hyperglycaemia which follow on from adipocyte insulin resistance and elevated FFAs especially in the presence of a high dietary carbohydrate intake. That will lead us to back to mitochondrial injury (which is probably where all of this comes from, did I even mention that obesity is a mitochondrial problem?), free radicals and I might even throw in gliosis. Which is interesting.

Peter

More of the 17% solution

2012-01-07T21:52:00.006Z

There are various little one-liner papers which I've tripped over in the last few weeks which are probably worth a post although are not related to the main things I'm interested in at the moment.

The first is an isolated oddity. We all remember Dr Axen and the 17% trans fat diet for rats? Followed by the Complete Idiots with their 14.4% solution.

Of course, no one would ever suggest feeding this much trans fat to humans in a weight loss study. Would they? No, surely not. Except I guess it depends on what you have to prove...

How about this study:

Let's do the math. The ketogenic diet provided bulk calories as fat, 100g/d. A scrummy 35 grams were saturated fat, nice. Next comes 34 grams of OK-ish monounsaturated fat. The obligatory 14g/d of disgusting PUFA is included. Now, maths is complex subject.

One plus one is, err, about, I mean, err, somewhere about one and three quarters. About. I think

OK, let's simplify. 35+34+14=100

Wrong. Yea Gods, I always was bad at math. My worst A level grade. Let's try again

100-(35+34+14)= n, where n is the trans fat content of the fat in the ketogenic diet.

Congratulations Dr Sears. You get the Axen Prize for the maximum undeclared trans fat content of an experimental diet used on humans.

Peter

Cake and cream

2011-12-31T23:39:00.003Z

Serving suggestions for soured cream not really needed...

The ginger cake (in the last post) isn't really low carb but it helps keep the children (and me) out of ketosis! Nice diluted with butter.

Ginger and Banana Cake ingredients:

3 medium or 2 large bananas
100g total of macadamias, almonds, walnuts
100g ground almonds
2 eggs
100g brown sugar
100g butter
4 tbsp black treacle
1 tbsp ground ginger
1 tbsp baking powder
2 tbsp yoghurt
150g rice flour

Happy New Year

Peter

Update

2011-12-19T21:32:00.002Z

Danish butter is on offer in at least one UK supermarket, currently 10% less than economy butter. Surprise surprise. No better way to eat (gluten free, lowish carb) ginger cake:

Look at that bite. That's my catastrophic tooth organisation! That really is how my teeth developed as a youngster. Not much to be done about that nowadays...

On the baby front the carnivory continues:

And I've largely replaced creamy cocoa with chocolate butter:

One 100gm chocolate bar (85% or 90%), One 250gm block of economy butter, 45ml double cream, 15 or 30ml honey and some vanilla. Melt, pour in to an ice cube tray, freeze, pop out of tray while frozen, keep in fridge until consumed, not very long...

It partly settles out unless you are very careful with temperatures but tastes none the worse for that.

Reading wise it's still all mitochondria and there are a million things to check but it remains interesting in the extreme.

What with the children's birthdays, Solstice, Christmas etc there is not a lot of free time but I'll get some posts up sometime!

Happy mid Winter Festival time to all

Peter

Brings back memories of last year's Solstice, driving across the Acle marshes in to a brilliant dawn with a lunar eclipse in the rearview mirror. Lovely to live just above the adjoining marshes nowadays.

Adipotide and the Bad Fat

2011-11-21T06:53:00.002Z

Just a brief respite from mitochondria:

Adipotide is a drug which targets the blood vessels supplying adipose tissue. It causes impressive fat loss by killing fat cells. Anon posted these two links on the last post.

There are other processes which can produce adipocyte destruction. We've discussed both acquired and congenital lipodystrophes in the past. They produce whole body fat loss with progressively deteriorating glucose tolerance because fatty acids have no adipocytes to enter, so end up accumulating in all tissues, producing pathological insulin resistance and diabetes. This is basic physiology and exactly what you would expect.

Adipotide is different. It produces fat loss with improving metabolic conditions and decreased hunger. How come a dead adipocyte is good from Adipotide and bad from auto immune attack?

Alex emailed me the full text. Here is the snippet from the email conversation which was my initial take on what might be happening:

"How does the drug get any improvement? You'd need to see the data and how they generated it but if the drug preferentially targets abdominal fat there would be an improvement in systemic insulin resistance until enough total [whole body] fat cells were lost for the overall for deterioration in insulin sensitivity due to muscle lipid accumulation to precipitate diabetes.

Of course during lipolysis you would have FFA release acting like an obese fat cell becoming insulin resistant and sending FFAs systemically to most non CNS mitochondria... Reduced need for food and increased ATP for activity from the metabolic flexibility perspective..."

Look here: Surgical removal of visceral fat improves peripheral insulin sensitivity (there's a lot I could write about this paper but no time). This paper looks OK, other papers by this group are very dubious.

Visceral fat seems quite important, here's an early brief review.

And here is the only quote we need from the Adipotide paper (thank you Alex for the full text):

"MRI and DEXA imaging confirmed that weight loss in the rhesus monkeys occurred primarily because of visceral fat loss."

Now, that's all hunky dory. What is the question we need to ask? Actually, there are a few:

Why is visceral fat Bad Fat? Why do we make it? If we get rid of the Bad Fat, will health be Good for ever? Did we evolve Bad Fat to kill ourselves? Is there a survival benefit from Bad Fat if we continue to drink >30% of our calories from fructose based drinks? Would having our omentum removed do good or bad things long term if we continue to mainline fructose? Would we need to get rid of our Bad Fat if we poured the Fanta down the urinal rather than down our throats?

I rather like Bad Fat. It opens all sorts of avenues of thought. There's so much about it that fits together but no more time to blog at the moment.

Peter

LIRKO mice (3) The MCQ

2011-11-10T06:30:00.005Z

I see the LIRKO mouse has resurfaced as a destructor of the role of insulin in obesity yet again. I've posted on the LIRKO mouse in the past so this little quizz should be quite straight forward. I skipped the questions about leptin because I felt like it.

WARNING some of the questions may have more than one correct answer.

Q1. What is the blood glucose of a LIRKO mouse after a mouthfull of chow?
a. 400mg/dl
b. 400mg/dl
c. 400mg/dl
d. WTF, no one told me LIRKO mice are intensely diabetic.

Q2. What is the urine glucose concentration of a LIRKO mouse?
a. Some
b. Quite a lot
c. More than quite a lot
d. Obesity researchers boil it down to make jam.

Q3. The liver of a LIRKO mouse has no access to glucose. Where does it source it's energy?
a. Not from glucose
b. Definitely not from glucose
c. Absolutely, definitely not from glucose
d. Where's the fat?

Q4. How much fat is there in mouse diet F9?
a. Not a lot.
b. Not a lot
e. Not a lot
d. 10%, just about enough to run the liver on, rather badly, giving early onset cirrhosis and death.

Q5. How much de novo lipogenesis (DNL) from glucose is done in the liver of a LIRKO mouse?
a. None
b. Zero
c. Zilch
d. LIRKO mouse liver can't take up glucose for anything because it has no insulin receptors. Ha ha, gotcha, this is a trick question.

Q6. If the dietary fat is used to run the liver and there is no DNL, where does the fat in adipose tissue fat come from?
a. Thin air.
b. Spontaneous generation
c. Beamed in from The Enterprise
d. A small nuclear reactor
e. It doesn't, you can't put in what you haven't got. OK, there is a smidge of DNL in adipocytes.

Q7. If a LIRKO mouse at the gym is losing more calories down the urinals (where glucose is collected for making jam) than it burns on the treadmill, why doesn't it eat more?
a. Blood glucose is 400mg/dl
b. Blood insulin is 80ng/ml
c. Both.
d. Yeugh, is that really how they make jam?

Q8. The LIRKO mouse is hyperinsulinaemic. By how much does this lower plasma free fatty acids?
a. By 40%
b. By 40%
c. By 40%
d. By only 40% because adipocytes, like the rest of the mouse, are intensely insulin resistant.
e. WTF, no one told me they had depressed FFAs.

Q9. How would the LIRKO mouse cope with a saturated fat based, intensely ketogenic diet?
a. Well
b. Really well
c. Really, really well
d. Don't ask, don't even think about it.

Q10. Obesity researchers trot out the LIRKO mouse because:
a. They want to share
b. They want to share
c. They want to share
d. Shut up and eat your carbohydrate. You need insulin to get slim. Mmmm LIRKO jam...

Peter

Metabolic flexibility and the identical twins

2011-11-04T06:49:00.009Z

This post is highly speculative. It doesn't have any answers. Here is a nice quote to begin with:

"If you want to retain your sanity, don't try to read a textbook on mitochondrial diseases"

This is from Nick Lane on page 281 of Power, Sex, Suicide. I was going to copy out the preceding paragraph but I guess everyone has their own copy of PSS. If not, you know what to do.

Now think about your sanity if you are dealing with a problem like obesity and you don't accept it's mitochondrial... Also think about the likelihood of successful intervention.

So I'm putting this up as a one-liner-which-grew because Liz dropped this paper me a few days ago and I got chance to open it today (OK, over a week ago!).

Enrol monozygotic twins in Finland. Hunt out BMI discordant identical twins (they are very rare) from the study, ie pairs of genetically identical people where one gets fat and one doesn't, despite their identical nuclear genes. Do lots of studies, get a Nature publication or ten out of it and decide obesity occurs because folks eat too much and move too little. Go to the top of the class as obesity researchers. There's a lot of it about.

Let's pick through the discussion and look at some of the conclusions from the metabolic flexibility point of view:

"a slightly higher birth weight (193 g) was observed for the twin that developed obesity during early adulthood, but this difference disappeared by age 6 months and the growth patterns of both twins were virtually identical until the age of 18 years, after which BMI differences between the co-twins became statistically significant (Figure 3)."

Pre-obese half of the pair of twins were heavier at birth, ie heavier in-utero. They must have been sneaking out to Macdonalds while telling their mother they were off to the gym. Amazing what some pregnant women will let their foetuses get up to. Next:

"After age 8, the pairs who later became discordant for obesity were heavier than the population mean, raising the possibility that genetic or environmental factors predisposing to obesity may be present in both co-twins of the discordant pairs. It therefore remains an open question as to whether the lean or the obese co-twin actually is more closely following the genetic predisposition."

Both twins have identical nuclear genes. These may or may not predispose to obesity, who knows? The obese twin has more defective mitochondrial genes than the one who remains slim. Each followed their need to produce adequate ATP. The one with worst mitochondria had to become obese to get there. Even the "slim" twin was heavier than average. His mitochondria might not have been so hot either, but not bad enough for serious malfunction. Next:

"The results suggested that physical inactivity in adolescence strongly predicted the risk for obesity (OR 3.9) and abdominal obesity (OR 4.8) at age 25, even after adjusting for baseline and current BMI."

Physical activity in adolescence is difficult if you have inadequate ATP production, so is minimised. At this age the affected twin is pre-obese. Obesity is necessary for elevation of FFAs to a level which will normalise ATP production to allow normal physical activity with sub normal mitochondria. Insulin will raise fat depots to an adequate size to elevate FFA supply due to adipocyte insulin resistance, once childhood growth has ended. Next:

"At age 25, the obese co-twins were only half as active compared with their lean co-twin as demonstrated in the 7-day accelerometer measurements.31 However, the total energy expenditure and activity-induced energy expenditure from the doubly labelled water did not differ between the co-twins. This discrepancy may be explained by the fact that the obese twins, while moving on average less, do expend more energy when they do because of their higher body weight."

THERE IS NO DIFFERENCE IN ACTIVITY OR CALORIE INTAKE BETWEEN TWINS ONCE OBESITY IS ESTABLISHED. An obese person moving from standing to sitting to standing again is doing a much weightier squat than the equally-idle-but-apparently-active skinny person with no fat to lift. Fatties may look idle because they don't get up from their chair if they don't have to but THERE IS NO DIFFERENCE in energy expenditure AT ALL compared to those equally "lazy" skinny twins who get up a few more times to burn the EXACTLY the same calories. OK, I've stopped shouting now. Doubly labelled water. Next:

"The basal metabolic rates (as measured by calorimetry) were considerably higher in the obese co-twins, presumably for the same reason."

Repeat shouting from previous paragraph. Plus, oops, they could have been talking about the Pima and forgot to mention that post prandial thermogenesis was depressed by almost exactly as much as BMR was increased.... Heard that before? I've not gone in to the logic of what is happening to BMR vs post prandial thermogenesis but it will undoubtedly come down to mitochondrial function. It just amused me that these established stars of obesity research were so familiar in their technique of citation. Next:

"The prospective Norfolk study of 20 000 men and women showed physical activity to attenuate the genetic predisposition to common obesity by 40%, as estimated by the number of risk alleles carried for 12 recently identified obesity predisposing loci.34 In the same study, the genetic risk score was positively associated with weight gain in inactive subjects, but negatively associated in physically active subjects."

No no no no. This appears to be saying that certain nuclear genes are associated with obesity if you are lazy. HOWEVER exactly the same genes are associated with you being THIN if you are active. I've not chased the EPIC paper because it's pure observational stuff but that's what this quote appears to claim EPIC is saying. Correct me if I am wrong. One explanation is that they are looking at the wrong set of genes. Obesity is a mitochondrial disease. It doesn't matter too much what your nuclear DNA says. You need good mitochondria to allow you to be physically active without needing you to be obese to improve ATP production. Duff mitochondria only allow you to be active if you have accumulated enough adipose tissue to trickle out FFAs. Next:

"However, the more objective measures via doubly labelled water revealed a substantial reporting bias by the obese co-twins: the under-reporting of energy intake (3.2±1.1 MJ per day) and over-reporting of physical activity (1.8±0.8 MJ per day) in the obese twins equalled to as much as one Big Mac hamburger, a 16-oz bottle of soft drink and almost 90 min of walking (3 m.p.h.), respectively. Interestingly, however, when asked to compare their own eating habits and physical activity to those of their co-twin, both co-twins openly reported that the obese co-twin had an unhealthier lifestyle with overeating, snacking and an irregular eating pattern as well as less physical exercise (Figure 4)."

This is a lovely paragraph. I think I have to accept from doubly labelled water that fatties lie about their caloric intake. This is very surprising. By doubly labelled water fattie twins do NOT eat any more than slim twins. They do not exercise less. Calories in and calories out are IDENTICAL in the obese and slim halves of the pair. Why should the fatties lie and claim to eat less than their skinny twin? Because they're fat...

I think it is also worth saying that the obesity-destined twin was noted, by all and sundry, to be "overeating, eating badly and eating irregularly" from an early age, with a preference for fatty foods. However I would comment that they did not even begin to become obese until 18 years of age and by 25 years of age doubly labelled water showed... etc etc etc. This moral failing as youngsters might just be translated as the pre-obese half of the pair were HUNGRY at that time. Life is hard when the world views your moral failings at the snack bar as evidence of your lack of will power. Being hungry is no fun. Being hungry because your adipocytes are not fat enough (yet) to ignore your hyperinsulinaemia and let you, grudgingly, have a few FFA molecules from their hoard is somewhat unfair. Your skinny twin is not hungry. He has mitochondrial ATP to spare. He sniggers at your third helping of pizza at your 18th birthday party because he has no gnawing hunger. He knows that you lie about how much you eat by your 25th birthday party. But by then he is eating EXACTLY the same as you are... At the gym, where he is well known, he only burns as many calories as you do walking up stairs. DOUBLY LABELLED water. Life is unfair. Next:

"Environmental influences independent from acquired obesity on liver fat were evaluated based on questionnaires and food diaries. Alcohol consumption from detailed questionnaires of the obese (3.7±0.9 doses per week) and non-obese (3.9±1.1 doses per week) co-twins did not differ and intra-pair differences in alcohol intake did not significantly correlate with differences in liver fat (r¼0.30, P¼0.14). Analysis of data from food diaries showed that the percentage of energy from fat (r¼0.37, P¼0.02) and saturated fat (r¼0.38, P¼0.005) did correlate with liver fat.5"

OMG it's the FAT (see end note), and it's the arterycloggingsaturatedfat (©Mary Eades) too. Phew. Fatty liver is due to (oops, I mean associated with) saturated fat intake. Not with Fanta. The ref for this is free to view. They, surprisingly, never did check the sucrose (or trans fat) intake against fatty liver. I don't suppose anyone thinks sugar has anything to do with fatty liver. Certainly it's not worth a line in the food breakdown table, even though it's probably just a click of the mouse away in the food analysis software... I seem to remember an obesity researcher pointing out that the obesity rise in the USA is associated with a fall in starch intake over 100 years and forgetting to mention the concurrent rise in sugar intake. There's a lot of it about. Excellence in obesity research, that is.

It gets better. The same group looked at fat preference. They really looked at fat preference. Not Fanta preference. They ONLY looked at fat preference. Perhaps there was no Fanta preference, it's not needed if the damage is already done. But the abstract gives no suggestion that they looked at anything other than fat... What answer did they set out to find? As I mentioned, there's a lot of it about.

Here's the scenario. Both twins get home from school. Pre-obese is hungry. Sneaks in to pantry and finds... Dadahhhh, a block of butter! You believe he skipped on the cookies sitting there?

Monozygotic twins have identical nuclear genes. They normally have very similar mitochondrial genes. But if there is mitochondrial heteroplasmy in the oocyst and one twin gets a bigger share of the decent mitochondria while the other gets a duff lot as they separate in-utero, things will be different. There will a discordance in BMI which develops in the attempt to normalise ATP production in the obese twin. The pre-obese twin is pre-obese in utero.

This would all be hunky dory if the mitochondrial heteroplasmy existed, with differing mitochondrial mutations between the twins. It doesn't, apparently. We find this snippet towards the end of the review paper:

"A novel finding of great interest in our obesity-discordant MZ pairs was the dramatic reduction of copies of mitochondrial DNA in the adipose tissue of the obese co-twin.12 Although the sequence of mitochondrial sequence was identical between the MZ twins (no evidence of heteroplasmy), the copy number of mitochondrial DNA in the obese co-twin’s adipose tissue was only 53% of that of the lean co-twin."

Sorry about the odd sentence in exactly the place where we want clarity, that's just how it is. Anyway, no evidence of heteroplasmy. But let's go and look up Ref 12.

This gives us this line:

"The mtDNA sequences of fat showed no evidence for heteroplasmy in co-twins, nor potentially obesity-associated sequence changes between obese and non-obese co-twins in fat or in leukocytes (Figure S1)."

I guess this might mean (as originally cited) that the sequences were identical between obese and normal twins, but it actually says there were no "potentially obesity-associated sequence changes between obese and non-obese co-twins", which may or may not be the same thing.

The next move is to another supplementary document which gives us this text (you don't have to read it if you don't want to):

"Analyses of mitochondrial sequence and copy-number

Known mitochondrial DNA sequence variants were extracted from MITOMAP database (www.mitomap.org) and variant information was annotated to the selected reference sequence AC000021.1 (GI:58615662) from GenBank. PCR primers were selected and re-optimized among those presented by Sigurdsson et al 7. Sequencing primers were designed to avoid known variant positions using The PCR Suite 8. The mitochondrial genome was PCR amplified in two overlapping ~9 kb fragments. PCR amplification was performed using 20-30 ng of DNA, 14 pmol each primer, 200 μM dNTP 1,4 U of DyNAzyme EXT DNA polymerase in 1X DyNAzyme EXT buffer (Finnzymes). Thermocycling consisted of denaturation of DNA template in 94ºC for 2 min followed by 30 cycles of 94ºC for 20s, 60ºC for 30s and of 72ºC for 4 min (extended for 10 s / cycle) and final extension of 72º for 15 min. Correct amplification was verified by agarose gel electrophoresis. PCR products were ExoI / SAP purified and sequencing was performed with BigDye3.1 chemistry on an ABI 3730xl DNA Analyzer. Mitochondrial consensus sequences and sequence variants were determined with SeqScape Software v2.5 (Applied Biosystems). Oligonucleotide sequences used in PCR and sequencing are presented in the Appendix of Supplementary Methods (vide infra)."

This is, to my rather limited experience, a standard PCR and sequencing protocol and is essentially guaranteed to produce mtDNA homoplasmy. Why? The number of abnormal mtDNA sequences is low amongst a huge number of normal copies. If you want to find heteroplasmy you have to individually sequence lots and lots and lots of mtDNA strands. Running a standard sequencing machine will not hack it.

The situation is clearly explained here. As they say:

"Here, we describe digital sequencing of mtDNA genomes using massively parallel sequencing-by-synthesis. Though the mtDNA of human cells is considered to be homogeneous, we found widespread heterogeneity (heteroplasmy) in the mtDNA of normal human cells. Moreover, the frequency of heteroplasmic variants among different tissues of the same individual varied considerably"

I've struggled with the methods to this paper and I'm not sure how many mtDNA strands they sampled from a given tissue. I think they might have done quite a few. This paper adopted a similar approach. Looking this hard you tend to find heteroplasmy if it is there.

It's there.

There are some interesting ideas in both papers about how heteroplasmy gets in to various tissues at various levels but they didn't go so far as to consider identical twins with mismatched phenotypes. A pity, because I think they know a great deal more about this than I do.

An obese twin has only 53% of the mtDNA of the slim one in their adipocytes. How about muscle cells? We know from the EMs of insulin resistant offspring of diabetic parents that their muscle mitochondria are grossly abnormal. We find from the twins study that lots of mtDNA (and presumably the mitochondria which might have originally contained it) simply isn't there.

It must be rather hard to find the mtDNA of mitochondria which are not there. Or mtDNA which is only there in very small copy numbers in the surviving mitochondria.

I personally doubt the mtDNA was homoplasmic in the obese twins. The unanswerable question is whether the heteroplasmy is responsible for the decreased mtDNA count...

There are a whole stack of ideas from the twins papers which need looking at from the mitochondrial selection pressure perspective, what controls mitochondrial number and how mitochondria control nuclear genes for their own synthesis...

Peter

BTW, compare these two abstracts, both from Finland Twins studies group:

Obese people love fat, always have done, 2002

Obese people now eat "avoiding fatty foods" while still indulging in "restrictive eating, frequent snacks, eating in the evening"... Same group 2007. Not snacking on blocks of butter after all then!

Both obese twins are considered, by these researchers, to have identical homoplasmic mtDNA in 2011. When will they change their minds on this? Soon I hope.

The Adipostat balloon

2011-10-12T05:11:00.009Z

Right, back to links from Mary Rogge's paper on the role of impaired mitochondrial fatty acid oxidation in the obese.

She links to Ruderman's mini review, which we will come back to in some detail in future, and there we find this excellent graph:

I rather like this graph, although it could theoretically be reduced to one line of text. The bit I like best about it is that you can play Pin the Donkey Tail on it. We'll play later.

The graph shows that lipid oxidation, as indicated by respiratory quotient, is well below normal in both pre-obese and post-obese people.

But not in the obese.

No, the RQ of an obese person is, from the graph, somewhere around 0.825, ie an obese person actually runs their whole body metabolism slightly more using fat vs carbohydrate than a non obese person, who has their RQ at around 8.5 when on a mixed diet.

It is only the pre-obese or post-obese who run their metabolism on carbohydrate (poorly) and fail to oxidise fat, their RQ panning out up at 0.875.

If we ignore causes of mitochondrial dysfunction for the time being, we can look at these situations logically. I'm loathe to use analogies but they are useful on occasions. Here's one, highly factual and probably quite relevant:

Take a type 1 diabetic with complete failure to produce any pancreatic insulin. Ask them to volunteer to skip their exogenous insulin, become both profoundly hypoinsulinaemic and markedly hyperglycaemic. Then use a tracer to measure their glucose metabolism. Can they use glucose? Of course they can. This was done back in 1978 and the results are quite clear cut. Acute hypoinsulinaemia can be compensated for by acute hyperglycaemia.

Now, the question is whether there is a situation existing at the mitochondrial surface, as relates to fatty acids, which is analogous to that at the cell membrane surface as regards glucose. Glucose uptake is controlled at the cell surface. Fatty acid uptake is (predominantly) controlled at the mitochondrial surface.

Can we increase intracellular free fatty acid derivatives to the point where energy production can be forced back up to a semblance of normality in the abnormal mitochondria of a pre-obese person?

The graph of RQs suggests to me that this can indeed be done.

However it requires an increase in FFA delivery to the tissues well in excess of what a normal person might oxidise. There needs to be enough of an increase in FFA delivery to the tissues to reach the point where FFA derivatives can be "pushed" down an adequate concentration gradient in to mitochondria to restore adequate ATP production.

The cost of this maneuver is in increased FFA intermediary-derived insulin resistance and even greater failure to use glucose.

If you are having even more problems using glucose because you have managed to get your fat oxidation up by increased lipid derivatives within the cytosol, where would you expect your RQ to be compared to someone who has free choice in metabolic substrate utilisation? More fat, less glucose. So the RQ will be.....

Lower of course. Somewhere around 0.825 I would guess, looking at the graph.

You can see why I like this graph...

So we know that the pre-obese and post-obese have problems burning fatty acids in their mitochondria. We know the currently-obese have corrected this defect by increasing fatty acid delivery to their mitochondria at the cost of worsening insulin resistance.

How do we increase fatty acid delivery to the cytosol? Fatty acid delivery is primarily controlled at the adipocyte level. Insulin, acting on normal adipocytes, inhibits lipolysis. Have I ever said that before?

Adipocyte insulin resistance is the direct equivalent of relative hypoinsulinaemia. If we simply stretch our adipocytes to the point where they no longer listen adequately to insulin we can increase FFAs delivery to the blood stream and so increase their delivery to cytosol and get to work pushing them in to whatever mitochondria we have.

In the state of established obesity energy production is, in fact, normalised.

Let's just set this out:

Mitochondrial dysfunction leads to cytosolic fatty acid derivative accumulation.
This leads to chronic hyperinsulinaemia via insulin resistance.
This leads to adipocyte distension.
This leads to adipocyte insulin resistance.
This leads to increased plasma FFA delivery at a given level of insulin.
This leads to increased cytosolic FFA derivatives.
This leads to mitochondrial ATP production being normalised.

The cost is increased insulin resistance. Oh, and the MECHANISM for improved ATP production is OBESITY. Call this a cost if you wish.

BTW: Of course there is a second set of discussions related to adipocyte mitochondrial dysfunction but I'll leave that out to keep it simple here.

Okaaaaaay.

Time to play Pin the Donkey Tail.

Everybody needs a drawing pin (thumb tack?). And a piece of string attached to it to represent the donkey's tail. It is traditional to have a picture of a tail-less donkey taped to a cork board and to try and pin the tail in the correct place, while blindfolded. I'll let everyone off of the blindfold and we can have this nice blue balloon as a substitute for the picture of the tail-less donkey.

It would be very helpful, if you are doing this at home, to write "Adipostat Hypothesis" on the balloon, most easily done before you inflate it. I couldn't be *rsed to do this, as always.

Now pin the tail, using the thumb tack, on to the balloon.

Pop!

Oops. Did you just pop the set point hypothesis of obesity? Clumsy of you, but easily done.

Obesity is a method of normalising ATP production. The concept of an adipose tissue "set point" is an artefact of how much adipocyte distension-induced insulin resistance is needed to normalise tissue ATP production at a given level of mitochondrial dysfunction.

Confession time. I never meant anyone to pop a real balloon. You don't have to actually do it. What I really wanted everyone to do was to pin a hypothetical donkey tail to the graph at the top of the post.

You need to guess what the respiratory quotient is for a person who, for the last seven days, has been eating a diet which included less that 20 grams per day of carbohydrate, around 60 grams of protein and as much butter as they like.

All you have to oxidise outside of your brain is fat. Your RQ will plummet to the lowest value possible short of full starvation. FFA delivery to non neural tissue will rocket. Glucose delivery will be irrelevant and the role of insulin in energy production will be sidelined. Cytosolic FFA derivatives will sky rocket too, to keep you alive using physiological insulin resistance, dontcha-no.

Perhaps you will normalise your ATP production?

Might you normalise your appetite too as you normalise your ATP production? It happens for many who try it...

Peter

I think ATP, AMP and AMPK might be an interesting subject to move on to next.

Adipocyte insulin resistance

2011-10-06T20:10:00.000Z

It was in late 2007 that I first blogged about the concept of adipocyte insulin resistance and of course it is back in my mind while I work through ideas on metabolic flexibility and insulin resistance in general. It is a very simple concept that the fatter adipocytes become (using whatever delivery system you like, ASP if you must) the harder it becomes to push more fat in to them. And certainly the harder it becomes to keep it there once it is installed. So this idea of adipocyte insulin resistance limiting fat gain is very intuitive and probably correct. How big adipocytes can get is probably determined by how strong your pancreas is combined with how responsive your adipocytes are to insulin as they swell. A pancreas of steel and relatively insulin-resistance resistant (no typo) adipocytes combine to get you to the over 200kg mark. This came up in comments on the last post. Is this true?

A rather nice paper was published back in the 1960s showing this very clearly. I have seen it cited as purporting to show that elevated fasting insulin is a consequence of obesity, rather than a cause. This is a fascinating and rather counter intuitive concept, so you just have to go have a look see at the paper. Luckily it's free access.

It does show, very convincingly, that adipocyte size correlates with adipocyte insulin resistance on the adipocyte cellular level. I rather like that.

It also demonstrates quite clearly that forced, brutal adipocyte size reduction by a couple of months on a 600kcal/d diet improves adipocyte insulin sensitivity as adipocyte size shrinks.

There are two core concepts which need to be taken away from this paper.

The first is that as adipocytes swell they become progressively less able to respond to insulin. This obviously translates in to insulin resistance of adipocytes ultimately limiting fat gain within the limits of the pancreas to secrete or hypersecrete insulin. That is if you accept that insulin is in any way involved in fat storage.

Now. What does this mean for the carbohydrate hypothesis of fat gain?

It is the RESISTANCE of adipocytes to insulin which limits fat gain.

And the corollary is??? Sensitivity to insulin drives fat gain. You can't have one conclusion without the other.

Anyone telling you that adipocyte insulin resistance limits fat gain and yet insulin per se has nothing to do with fat gain... Well, you decide. I have.

Although the group measured many, many things the only information we get about fasting insulin levels and post challenge insulin levels are these five paired graphs:

There is nothing in the text or tables giving any numeric data about insulin levels in obese individuals and no details at all from the normal groups. I don't mind this too much as the study was really aimed at adipocyte size and adipocyte glucose metabolism in response to exogenous insulin. This was the main drive of the paper. Note that they didn't look at adipocyte beta oxidation, no one had any idea this might be compromised back in the 1960s, so we get no idea about the ability of adipocytes to carry out this essential function.

Look, fasting insulin in five obese people is not generally elevated, it's reported as being only slightly elevated in two out of the five obese patients. This obviously implies that elevated fasting insulin does not predict weight gain. There we go. Time to pack up and go home.

Ah yes, but which fasting insulin are we looking at? Remember that group of starved obese folk we chatted about previously who had three different fasting insulin levels? One level on their normal (obesogenic) diet, one on a calorie and carbohydrate limited diet and another on the full starvation non-diet (ie complete carbohydrate restriction): 45 or 38 or 15-20 microIU/ml.

In obese people (but not in people who have normal metabolic flexibility) you can simply dial fasting insulin by carbohydrate intake. The question we cannot answer from Hirsch's study is what the fasting (and the 24h AUC) insulin values were for the five obese participants while they were free living on their normal obesogenic (high carbohydrate, you can bet) diet and slowly gaining weight? Remember we only need an average of 5g/d adipose tissue accumulation for long term obesity.

We are given an insulin value during phase I on a weight stability diet with a carbohydrate intake fixed at 45% of not-quite-enough-for-comfort calories. This is not what a given individual would normally choose to eat. In real life these people would not be on a weight stable diet. They certainly would not have been limiting their carbohydrate to 45% of calories. So we have no idea what their fasting insulin level would have been before stabilisation on phase I, but is certainly going to have been higher than the graphs show.

After massive weight loss during phase II of the study (on 600kcal/d for several months, probably only bearable because carbohydrate was limited to around 50-55g/d and the doors were locked [jk!]) we go in to phase III and get our second set of curves. Here we are now maintaining weight stability at a markedly reduced body weight with a smaller portion size of a still 45% carbohydrate diet, so total carbohydrate intake will be a bit lower. Hence the slightly reduced fasting insulin... But of course none of this represents the life which led to the enrolment in the study.

Subjects will be hungry.

While ever they stay hungry and limit carbohydrate to 45% of their never-quite-enough calorie intake, their insulin levels will stay low and they will, hungrily, stay slim.

Four of the five patients managed this for quite some time. Kudos to them and their willpower. You have to wonder about the fifth patient. Lost to follow up? Not lost to follow up but fatter than pre study? Just got fed up with people sticking needles in their butt?

How effective for long term weight control is chronic caloric restriction? Answers on a postage stamp to...

Are these people fixed? Their adipocytes certainly have scope to respond better to insulin and will inhibit lipolysis more effectively than during obesity. This limits FFA leakage due to insulin resistance which decreases FFA delivery to muscles and so allows muscles to take up glucose better, so both glucose and insulin curves improve. But are they really, really fixed? Will they will simply regain their lost weight, unless they enjoy being hungry all the time? Especially if they increase their total carbohydrate intake? And why are they hungry? Another post in this series there.

Addendum: Running through the methods section of Petersen's paper it is actually worth noting that fasting insulin and simple derivatives of fasting insulin plus glucose, such as the HOMA score, are rather blunt instruments for picking up insulin resistance. The more complex insulin sensitivity index is better but even this failed to pick out two out of twelve apparently insulin sensitive participants who turned out to be insulin resistant on the hyperinsulinaemic clamp, the current gold standard for picking out insulin resistant subjects. So, while insulin resistance is core, simple fasting insulin has to be accepted as a blunt instrument. Clamps, unfortunately, are not simple to perform. End addendum.

Of course you cannot dial fasting insulin by carbohydrate intake in normal individuals. So all you have to do is include enough normal people in your longditudinal studies and there will be no significant correlation between fasting insulin and subsequent weight gain. What would you expect?

Anyhoo, back to adipocyte insulin resistance. Stretching adipocytes appears to have effects on their sensitivity to insulin. As adipocytes stretch this translates in to progressive pathology as the adipocytes are running out of their ability to function normally. As they get fatter they leak more FFAs at a given level of insulin. This is important. Very important.

Before we go on to the next post: Is there any other form of adipocyte insulin resistance, other than that due to fat distension?

I rather like physiological insulin resistance. It keeps me alive. Simple carbohydrate restriction or a couple of days of frank starvation produces whole body insulin resistance to spare glucose for brain use. You know what I mean. Take a young fit healthy human and starve him for three days and he will immediately become intensely insulin resistant on a whole body basis. If not he would become intensely dead. Are adipocytes part of this physiological insulin resistance response, in the same way as muscle cells are?

We get a partial answer to this when Hirsch cites Tucker's study and suggests that the reason she found no difference between the adipocytes of obese and slim rats was because both were maximally insulin resistant after a 20 hour fast, even those from skinny rats...

"However, these studies were performed upon tissue from animals fasted for 20 hr, a manipulation known to decrease the insulin response of adipose tissue in vitro."

Ad hoc number 3523, but highly plausible. Every body knows this... Physiological insulin resistance mimics pathological insulin resistance. The mechanism through FFAs is likely to be the same.

This would again be logical as you do not want rats in starvation hanging on to their adipocyte energy stores or to be allowing precious glucose in to adipocytes (however little glucose adipocytes use) and so allowing it to be "wasted" when needed by the brain.

Is there a third factor affecting adipocyte insulin sensitivity?

Well, of course adipocytes have mitochondria. Are they breakable? Probably.

If you break them I would assume that they behave much like those in muscle tissue and they do the best they can with pyruvate while leaving the FFA derivatives in the cytosol, ie adipocytes should become insulin resistant if they have broken mitochondria. But this insulin resistance is not stretch related and it's not physiological. It's a mitochondrial break and could happen at any stage of distension of adipocytes. So mitochondrial failure should lead to adipocytes leaking FFAs when glucose and insulin are elevated. Possibly at minimal distension size, ie while you are still slim.

This would worsen whatever state of insulin resistance the muscles were in from their own mitochondrial problems. If the pancreas is not up to overcoming the supplementary FFA-induced insulin resistance (due to its own mitochondrial problems as suggested by Petersen et al) then hyperglycaemia will result and you get that label of T2DM... Possibly while still slim.

The plateau in your weight here might be mistakenly attributed to the satiating effects of insulin on your brain finally kicking in, somewhat belatedly, after 50 years or so of hunger.

If you have an unbroken pancreas of steel you can still argue with the broken adipocyte mitochondria and you can still get even fatter. Ditto if you have T2DM due to insulin resistance and some joker gives you a bottle of injectable insulin plus some syringes. Especially if they also tell you to eat a ton of bagels and cover the hyperglycaemia with a ton of exogenous insulin. And chide you for overeating.

Peter

Summary: Adipocytes become fatter under the influence of insulin. Resistance to insulin by adipocytes limits fat storage and hence eventually limits weight gain. It also elevates FFA supply. Important.

Denmark purchased using Flora profits?

2011-10-04T05:32:00.007Z

Ali prompted me to put up this link and I see Barry Groves has something up about it too.

I think it was Iain Banks who wrote about corporate interests or massive personal wealth buying up a small country in the Himalayas, can't remember which novel it was. Fiction anyway.

Unilever appears to have bought Denmark. Where next for corporate take over? Hint, probably the UK, we're dumb enough. Probably not Hungary. At least the worst aspects of the Hungarian tax can be corrected with the shake of a salt cellar.

Peter

HOW MANY bananas a day?

2011-10-01T20:27:00.004Z

Our daughter eats everything. Her ultimate favourite food so far is a purée of pig heart casseroled in red wine. We tried her on a banana, head to head with 90% cocoa chocolate. My wife filmed the encounter.

The vocals at 19 seconds from the start sum it up.

Help was needed with the chocolate as it glues itself down to the tray, especially when well sucked!

Peter

Insulin resistant and slim. How slim?

2011-09-30T05:16:00.006Z

This Figure 4 from the paper by Shulman's group on mitchondrial dysfunction in the offspring of T2DM parents, the one the EMs came from in the last post. It gives a nice outline of the way they are thinking:

and this is a summary of some of the points which came up in the comments (there is a lot of information and links from the comments about possible causes and management for those interested) added to the figure:

While I was raiding this paper I thought I would also put up Table 1, the characteristics of the control and diabetic offspring groups:

Now you have to be very, very careful with these groups. They have been exceedingly carefully preselected. Fortunately the pre selection process is laid out in some detail in a previous paper from 2004:

"All subjects were recruited by means of local advertising over a two-year period (2001 to 2003) and were prescreened to confirm that they were in excellent health, lean, nonsmoking, and taking no medications. A birth weight above 2.3 kg (5 lb) and a sedentary lifestyle, as defined by an activity index questionnaire,(21) were also required. Qualifying subjects (more than 150 persons) underwent a three-hour oral glucose-tolerance test (with a 75-g oral glucose load), after which two subgroups of subjects were consecutively selected to identify extreme phenotypes for insulin resistance and increased insulin sensitivity.

Insulin-resistant subjects (3 men and 11 women) were defined as having an insulin sensitivity index (22) of less than 4.0 (indicating insulin resistance; lower values indicate greater insulin resistance), at least one parent or grandparent with type 2 diabetes, and at least one other family member with type 2 diabetes. Insulin-sensitive control subjects (five men and seven women) were defined by an insulin sensitivity index of greater than 6.3 (with or without a family history of type 2 diabetes)."

As I read this it looks like over 150 people were screened for insulin resistance. Of those 150 those with the best and worst insulin sensitivity were selected as controls or subjects respectively. BUT you were only allowed in to the insulin resistant group if you did have a relative with T2DM. We get no idea of how many people had awful ISI and no diabetic relatives, ie if there were any index cases who might represent the red scrible on the second picture. Maybe there were loads, maybe not. I can't find that information in the paper. So we have to be very careful, the T2DM-relatives aspects MIGHT be a complete red herring. The insulin resistance is not.

Soooooo, with that caveat in place, we can see that (completely observationally) the insulin resistant group had, by definition, elevated insulin (and poor ISI) and the control group didn't. The control group weighed 61kg, the insulin resistant group weighed 66kg. Hmmmm. Observational, cross sectional. Fascinating.

You could simply say that the insulin resistant group were only hyperisulinaemic BECAUSE they were 10% porkier than the svelt control group. Indeed, if you consider porkiness to be a result of simple overconsumption of calories, for whatever reason, this would have to be an effect, not a cause.

Shulman's group extend the concept of mitochondrial failure in muscles to a potentially related mitochondrial failure in beta cells during the discussion. That's an interesting idea. Let's go one further and think about mitochondrial failure in adipocytes... I know it's odd to think that adipocytes (or indeed their mitochondria) might have anything to do with obesity, but stranger ideas have been floated.

Peter

BTW they also mentioned genes which control mitochondrial biogenesis:

"In this regard it is of interest that a common Gly482Ser polymorphism of the peroxisome proliferator–activated receptor γ coactivator 1, a transcriptional regulator of genes responsible for mitochondrial biogenesis and fat oxidation, has been linked to an increased relative risk of type 2 diabetes in Danish populations as well as to altered lipid oxidation and insulin secretion in Pima Indians."

I just noticed that the alpha form of peroxisome proliferator–activated receptor γ coactivator 1 got an honourable mention back in one of the Fiaf posts on the control of host metabolism by the gut mircobiota...

Did you over eat yourself in to obesity or T2DM?

2011-09-22T19:43:00.004Z

I have read Mary Rogge's paper on the concept that impaired fatty acid oxidation leads to obesity. This post is not aimed as a criticism of her ideas but modifies them somewhat, simply by following references she cites in her text and maintaining an insulocentric viewpoint. Obviously the failure of beta oxidation is strongly challenged by the success of low carbohydrate dieting and supported by the success of (extremely) low fat dieting. Is it correct?

There are a fantastic number of pieces to the jigsaw puzzle of obesity in this paper, many of which are probably very important and I'll run through them as soon as I can get my head around which ones matter most.

The basic concept is that there are excessive fatty acid derivatives in the cytosol of muscle cells (and probably other tissues, the main thrust of the paper is toward muscle metabolism). Why I view this as supportive of the carbohydrate/insulin hypothesis of obesity is yet another post. This particular post is on some of the problems I have with the concept of a simple defect in fat metabolism as the cause of the accumulated fatty acid derivatives.

As so often there will be a series of stolen diagrams, scribbled over using Powerpoint, which probably break every copyright rule in the book... Oops. Here we go.

Okay, here is the basic concept as a straight copy-paste:

Uptake of long chain fatty acids in to the mitochondria is mediated through carnitine palmitoyltransferase 1 (CPT1, green box upper left hand side). This is suggested as the failed step.

But there are problems with the diagram. Look here:

Here we have citrate being exported from the mitochondria and converted to malonyl-CoA via "fatty acyl-CoA". I think it would have been much better to actually specify acetyl-CoA at this point rather than "fatty acyl-CoA", but that may be nit picking on my part. But it is ONLY acetyl-CoA which is liberated by the citrate shuttle. The function of the citrate shuttle is to get acetyl-CoA out of the mitochondria and in to the cytosol for fatty acid production...

Next we have this feature:

I'm not sure whether this arrow suggests that fatty acyl-CoA, straight from triglycerides, facilitates or activates the citrate shuttle (I can't find any suggestion of this being the case) or is being cited as a source of citrate, which it is not. For fatty acids to form citrate they have to under-go beta oxidation:

And this is not supposed to be happening because the malonyl-CoA is inhibiting CPT1 mediated transport of fatty acyl-CoA to the site of beta oxidation. Hmmmmm.

So where might the cytosolic malonyl-CoA be coming from? Is glucose supplying so much citrate that the obese can use it for malonyl-CoA production?

If we flick to this fascinating reference we can look at the TCA cycle itself, to see whether glucose is producing enough citrate to export for conversion to malonyl-CoA as the spanner in the works.

From the paper we can see that if you have a very complex magnetic resonance spectroscopy machine, which you are willing and able to home-modify (read the methods text!), some exceedingly complex computer models and a supply of carbon 13 labelled acetate tracer you can actually work out how active the TCA cycle is in normal vs insulin resistant muscle tissue. This paper is so cool.

Verdict?

The offspring of diabetic parents have crap TCA cycle activity in their muscle tissue. It will not be producing the amounts of citrate which might be exported for fatty acid synthesis. This is not a failure of beta oxidation. It is a failure of the TCA cycle in its entirety. The fact that obese people run their metabolism on glucose does not mean that they run it well on glucose.

Why is the TCA cycle so compromised?

This study has some excellent pointers. Look at this picture, it could be from an obese or diabetic individual:

These folks have odd muscle tissue.

a) They don't have many mitochondria, b) many of their mitochondria look crap and c) many of their mitochondria are dying.

They don't have a simple failure of fat oxidation, they have a failure of mitochondria full stop. It simply shows most clearly in the failure of beta oxidation.

I'll take a break now and put this post up. There are, of course, a whole stack of follow-ons to this. If you have duff mitochondria you accumulate fatty acid derivatives in your cytoplasm. They cause insulin resistance. Once you have insulin resistance you will be chronically hyperinsulinaemic and, in all probability, go on to develop obesity as a direct consequence of that hyperinsulinaemia. Let's make this plain. Mitochondrial dysfunction is present before obesity develops and does not revert to normal on forced weight loss.

Over eating is not causal. Whatever anyone tells you.

If you are an undamaged human being and you force overfeed yourself with FOOD, say in some tribal ritual, I would suggest that you will not do this to your mitochondria. You will continue to burn fat easily. You will not develop chronic hyperinsulinaemia. You will lose weight automatically after that cultural binge is, thankfully, finished and you can get back to life within your normal appetite.

Humans do such weird things to themselves! Culturally and accidentally.

Peter

Back on line

2011-09-17T05:25:00.009Z

Well that's me back from the AVA meeting in Liverpool. Highlights: Arterial blood gas sampling at the top of Everest, all rough quotes from memory:

"The peak was a bit 'peakier' that we had anticipated so we dropped down a few hundred feet to a more level patch before dropping out trousers in a 20 knot breeze at -24degC to stab each other's groins for arterial blood samples".

Getting to the top of Everest? "I never train" linked to "it's all mitochondrial" and "Ground level athletes really struggle on the big mountains, Ranulf Fiennes took three attempts to get to the top and it was very hard for him".

Reinhold Messner is STILL ALIVE (obviously he has remarkable mitochondria). OMG I thought he'd have made a single small mistake at some point before now. Having read some of his earlier achievements I'd never expected him to make old bones. But he must be older than me...

And the RN battlefield anaesthetist from Iraq/Afghanistan. "These guys come in needing one, two or even three amputations from an environmental temperature at up to 40 degC. One of the worst prognostic markers is hypothermia. We think it's mitochondrial".

A good friend (with an excellent brain, yes she has already read Power Sex and Suicide while moving from anaesthesia to obesity research) chatting about DMT2 in horses "It's all mitochondrial".

One of her co-workers on cartilage degeneration in arthritis "It's all mitochondrial".

I had a great meeting.

I got, without net access, to read through and analyse some of the implications of the downloaded papers on mitochondrial dysfunction in obesity from JS's page on metabolic flexibility. Needless to say these links are good but you HAVE to read the papers, follow the secondary links then read the methods. Needless to say there is a lot to say and I'm still not about to go carb loading.

Time to get the Baba-breakfast ready. I'll try to get to emails and read comments over the w/e, but life really is very busy.

Quote of the century: "It's all mitochondrial".

Oh, and it's not quite as simple as failure to burn fat.

Peter

A defect of fat metabolism and a few thanks

2011-09-12T05:20:00.007Z

I have, in the past, been given a key piece of information, put it in my pocket and left it there.

This is unforgivable, I know. But if the key is important enough you will have to either go through you pockets or be given another copy.

I am grateful to the rather unpleasant episode with Stephan as it allowed someone to supply me with that replacement key.

Metabolic flexibility is a slight misnomer, it describes a defect in fat metabolism.

I thank Stephan for getting me off my arse.

I thank Nick Lane for Power Sex and Suicide.

I thank M. for getting me to mention metabolic flexibility in comments.

I deeply thank J Staton for doing all of the work for me, reading Hyperlipid and taking the trouble to get the key cut then posting it to me via the comments. Go read.

There is no need to re invent the wheel. After reading the yellow box warning you can read this perfect quote

"This is a long and detailed article, but it’s very important".

And from elsewhere, if the post hasn't been taken down:

"A defect in fat metabolism?" Cracking quote, that one.

This fits with so many things which have become very, very obvious to me over the years. Neatly, logically, tidily.

Thanks all

Peter, the shoe-horner with the inappropriate prefix.

Should we abandon the carbohydrate hypothesis of obesity?

2011-08-28T19:20:00.157Z

I have read Good Calories Bad Calories. At just under a kilogram there are minor points within it with which I disagree. But, for the majority of the people who have read it, it is basically correct.

One of the most recent critical appraisals of the carbohydrate hypothesis of obesity was posted by Stephan over at Whole Health Source. Obviously, I disagree with Stephan's appraisal. That's fine, to disagree is perfectly OK. We'd get nowhere if we all sang from the same hymn sheet. This post is basically my take on the evidence used to destroy the carbohydrate hypothesis. It's depressing to have to do this but reassuring at the same time.

So why do I cling to this apparently incorrect and outdated hypothesis? Let's look at the points in approximate order as taken by Stephan.

A defect of fat metabolism?

Taubes ignored leptin to concentrate on insulin; this appears to be the main conclusion in this section. Stephan cites a neat paper by Leibel et al which demonstrated that in four healthy, never-obese humans the fall in metabolic rate induced by 10% weight loss could be reversed by physiological leptin replacement. That's cool if you want to be a young, fit, healthy, never-obese experimental volunteer desperate to live comfortably at 10% below your normal, slim weight.

If you are currently morbidly obese it may be of some comfort to know that leptin might be able to help you correct your hypometabolism should you manage to lose some weight.

If you are ex-morbidly obese and have managed to lose a few hundred pounds of fat you will still own a set of injured adipocytes. These injured adipocytes refuse to produce physiologically appropriate levels of leptin for their fat stores. Now THERE is a role for leptin. It might even reverse the persistent hyperinsulinaemia present even during starvation in the morbidly obese...

If you are currently morbidly obese and think leptin will help you lose weight, think again.

So do I think leptin is unimportant? Of course not. Does this invalidate the carbohydrate hypothesis? Shrug.

What about the morbidly obese ob/ob mouse, which cannot make leptin? There are a handful of human families on the whole of the earth with this problem. They need leptin and it will work for them.

The population of the USA is around 300 million. Of the adults in this population, as of 2008, 34.2% are overweight, 33.8% are obese and 5.7% are morbidly obese. They are not going to benefit from leptin supplementation to lose weight.

According to Stephan many, if not most, of these few million people will benefit, for reasons which are not entirely clear, from carbohydrate restriction. But it's not due to lowered insulin levels... Fascinating conclusion.

How can anyone be so sure that it is not from a reduction in insulin levels?

Here's why, watch very carefully:

You may think you have seen this clip before but no, although the child is the same the chocolate is different. This is 90% cocoa chocolate, none of your boring 74% sugary stuff...

If your baby is going to self feed chocolate you are going have to bath her. Bathing babies is dangerous. We also have one of these:

I always try not to throw out the baby with the bathwater. You can't be too careful...

The big problem with insulin, as any obesity researcher will tell you, is that it is a satiety hormone. I've said it before, all you have to do is have it injected in to your brain and you won't feel like eating a steak for the next few hours. Let's get a nice juicy quote from this paper by Velloso and Schwartz, hot off the press in 2011:

"A major and persisting source of confusion surrounding the hypothesis that insulin action in the brain reduces food intake and body weight while also lowering hepatic glucose production and increasing thermogenesis stems from evidence that following systemic insulin administration, the subsequent fall in glucose levels potently increases food intake while also increasing liver glucose production and reducing sympathetically driven thermogenesis. Thus, insulin-induced hypoglycemia potently overrides virtually all of insulin’s central effects, an observation that for many years has confounded research in this field."

Did you see the baby go? Here it is again:

"Thus, insulin-induced hypoglycemia potently overrides virtually all of insulin’s central effects".

That's it: Baby, bathwater, gone. How can anyone be so careless? Oh, did you miss it?

The baby is the peripheral effect of insulin on lipolysis, which is discarded without mention. Because hypoglycaemia in your brain (a central effect) makes you hungry, the fact that hypoglycaemia can steamroller insulin's central effects appears to have allowed the discard of insulin's peripheral adipocyte effects. Insulin's inhibition of lipolysis, in a normal human being, occurs at concentrations which do not even budge muscle glucose uptake. Infuse it directly in to the arterial supply to the fore arm and the systemic hypoglycaemic effect is lost. All you get at low infusion rates is inhibited lipolysis. This is the baby in the bathwater. Up the rate a bit and potassium uptake is increased. Bugger glucose uptake, this needs far more insulin that inhibition of lipolysis or promotion of potassium translocation. To summarise, if abnormally high insulin levels are needed to deal with unwanted hyperglycaemia then lipolysis will be inhibited until such a time as fat cells become so distended they refuse to listen to this excessive insulin, ie when they have become insulin resistant.

There are certain other spectacularly obvious problems with this accidental baby loss. Once we have all accepted that insulin is a satiety hormone it becomes perfectly obvious that people on low carbohydrate diets, with their chronically reduced insulin levels, should be hungry. After all, I have seen it suggested by Stephan that insulin might assist weight loss. I'm still trying to get my head around that one, while eating low carb and trying to remember what it felt like to be hungry. Trouble is it's all so many years ago... Of course, as Stephan points out, hypoglycaemia is a potent appetite stimulant. Again LC eaters, with their chronically low blood glucose levels, should be ravenous. I'm also trying to get my head round that one too. Reality occasionally gets in the way of great theories. Sigh.

I'm not quite sure where to put in the neuronal insulin receptor knock-out mouse. It's fat, so the conclusion appears to be that brain insulin receptors are important to satiety. I'm sure they are. However, these fat mice are also hyperinsulinaemic and will be lipolytically challenged. I love these particular KO-mice... They do not have me mainlining insulin as a weight loss drug. I love the impaired spermatogenesis and ovarian follicular maturation too. I still would not decry leptin here but these hyperleptinaemic mice don't do reproduction terribly well. Dare I use the I-word when talking about fertility?

Insulin inhibits lipolysis. Don't forget that when we come to talk about the Pima.

Before we move on let's look at the satiating effects of foods. Stephan's refs 4, 5, 6 and 7 suggest no macronutrient matters much and ref 8 shows protein is more satiating than carbohydrate. But reference number 9 is the absolute beauty.

Satiety is proportional to the insulin response to protein. Wow! Must be the anorexic effect of insulin.

But there are problems, wouldn't you guess. I don't have the insulin/glucose data following ingestion of any of the proteins mentioned in the abstract but let's look at the effect of casein, which I do have data for. The principle is identical.

Casein raises blood insulin level from 39pmol to over 100pmol and it's still at 90pmol by the three hour mark when sampling stopped.

Amen, RIP the insulin hypothesis.

Protein=insulin=satiety=anorexia=lipolysis.

But just a minute.... There is no sugar in casein, any more than there is sugar in beef. If we took these same seven volunteers and, without feeding them, injected them with enough exogenous insulin to raise blood level to 100pmol and peg it there while simultaneously locking the canteen door, they would die in hypoglycaemic seizures somewhere around the 10 minute mark. We could even throw in a little amylin (which obese people happen overproduce, odd that) to stop them being hungry as they die.

But elevating insulin to lethal levels using glucose-free casein, beef, whey, eggs etc all produce acute, severe, unremitting, paradoxical normoglycaemia.

I can't blame Stephan for not mentioning glucagon as it doesn't help destroy the carbohydrate hypothesis. Explaining the physiology seems to be my problem.

In healthy people eating neat protein there is a rise in glucagon which slightly under compensates for, as far as blood glucose is concerned, the rise in insulin. There is normally a slight fall in blood glucose.

Does glucagon increase lipolysis? It certainly does in pharmacological doses, as any physiology text will explain. In real life people seem rather unwilling to publish the data. You would have thought that 30 seconds on pubmed would have shelled out the effect of isolated protein on lipolysis but there you go, the insulin hypothesis, while defunct, discourages dabbling...

In this study they fed children consistent meals of mixed formula for a couple of weeks, then they switched them to a split meal protocol with most of the carbohydrate in the morning meal and all of the protein in the afternoon meal, fat being held constant for both meals.

The morning high carbohydrate meal suppressed FFAs as you would expect because insulin inhibits lipolysis. The afternoon meal of reduced carbohydrate, high protein content spiked insulin all right, but also increased FFAs. As dietary fat was held constant those FFAs almost certainly came from lipolysis. The group didn't measure glucagon but normoglycaeimia in the presence of insulin smells of glucagon to me.

Whenever someone does a hatchet job on the carbohydrate hypothesis using the insulinogenic index of beef without mentioning glucagon I am left wondering why they were carrying an axe in the first place. I find this thought very uncomfortable.

As a complete aside, people may enjoy this snippet on glucagon receptor deficient mice. You can eliminate the diabetic phenotype induced by massive streptozotocin overdose so long as glucagon cannot act. Interesting stuff but off topic really. But you cannot have death by lipolysis under hypoinsulinaemia without the lipolytic action of glucagon...

We next have two excellent studies correctly showing that resting energy expenditure is higher in both Pima Indians and schizophrenics in direct proportion to their hyperinsulinaemia. Oddly enough they don't simply melt away to size zero supermodels under the anorexic effect of insulin because their post prandial thermogenesis is depressed to almost exactly the same amount as REE is increased. Neat huh? Did you realise when you read the citation?

There comes a point at which fat cells become sufficiently insulin resistant that they cannot hang on to the their fat content. You can still put fat in there with minimal insulin and minimal insulin sensitivity. Once adipocytes are sufficiently insulin resistant and they are leaking sufficient free fatty acids to match input, obviously weight gain stops. The inappropriate spilling of FFAs causes palmitate deriviatives to be produced which worsen insulin resistance, whole body, and obesity flips in to diabetes.

I am in complete agreement with Stephan here. What I object to is citing a situation where insulin is failing to progress obesity, when it is doing its best to, as evidence it did not cause it in the first place. Insulin is trying and FAILING to make the adipocytes fatter. The more impossible the task, the more insulin is produced.

So we have a muscle cell, for example, which is wondering what the hell is going on as it sits in a sea of glucose and free fatty acids which is physiologically completely inappropriate. As we have been told by Stephan:

"Let me explain what the primary role of insulin is. It is to coordinate the metabolic shift between burning primarily fat, to burning primarily carbohydrate. Any time insulin suppresses fat oxidation, it increases carbohydrate oxidation by an equivalent amount. That is what it is designed to do."

In morbidly obese people, as they flip in to diabetes, this is EXACTLY what insulin is NOT doing. If you make fat cells more insulin sensitive (or generate some new, insulin-sensitive adipocytes), say with with PPAR alpha agonists, you will correct the elevated FFAs as insulin starts working on fat cells again and diabetes will abate slightly until the ability to store fat under the influence of chronic hyperinsulinaemia is once again lost, but at a higher fat mass.

I dunno, maybe PPAR gamma agonists simply increase food reward??????????????

Why is resting energy expenditure high in the obese? The body hates hyperglycaemia and wants to burn glucose whenever it's high. FFAs are a supply led system. Failure of adipocytes to respond to insulin increases supply. You then have excess glucose from the diet and excess FFAs from leaky adipocytes. You have to do something with the calories.

So does this destroy the "insulin locks fat away and decreases the metabolic rate of hyperinsulinaemic people" hypothesis? This has particular relevance to the multiple observations of utterly impoverished communities were adult obesity co exists with infant malnutrition. I would stress that this does not reflect the situation in the Pima community as studied in the 1990s, where childhood obesity has certainly been an issue and calorie malnutrition is not. Everyone has enough junk food to eat. Everyone can be obese, everyone can have enough calories to run a high REE, keep total caloric output down by decreased post prandial thermogenesis and still manage to gain a few grams of adipose tissue a day until diabetes sets in.

If there is enough obesogenic food for all, a mother will be hypermetabolic at rest and her kids will be fat. The insulin hypothesis predicts that if there is a restricted supply of hyperinsulinaemic food the mother will remain fat due to her hyperinsulinaemia, while the child will remain emaciated while ever she maintains some degree of insulin sensitivity.

Let's do reductio ad absurdum: Mother and daughter have 8000kcal of hyperinsulinaemia generating food available. Mother eats 4500kcal, becomes as fat as her adipocytes will allow her to, then she leaks FFAs from her adipocytes to become diabetic. Daughter eats 3500kcal and does the same. Both are hypermetabolic at rest, the mother more so as she is not growing. Both become obese.

Now lets say mother and daughter have 2000kcal between them. Mother eats 1100kcal, moves as little as she can, drops her metabolic rate, is hungry all the time but stays fat. Daughter eats 900kcal and is malnourished, becomes emaciated.

This is an aspect of the insulin hypothesis which has not been tested for obvious reasons. It will be correct, in my opinion. I am unaware of any evidence base for this.

As I understand the reward hypothesis, the mother and daughter eat a high reward diet, hit their dopamine system, desensitise it by over rewarding and this ups the hypothalamic fat set-point. Mother increases her calorie intake to maintain her set point level of fatness and eats her starving daughter's food to stay there. Fascinating.

The dietary practices of the Pima under severe calorie restriction are a complete unknown to me but I have serious problems with the reductio ad absurdum example I've just discussed. I've never met a mother who appears to behave that way, but maybe I've never met anyone with adipose depots far enough below their bodyfat set-point to behave this way...... Even folks on WeightWatchers seem mostly human.

So looking at modern Pima Indians or schizophrenics fed to satiety in no way tests the insulin hypothesis of restricted metabolism under conditions where insulin remains elevated and people are hungry. In fact Stephan's neat leptin reference suggests if we went in and injected the hungry, obese mother with leptin twice a day we would reverse her hypothyroid state, fire up a few uncoupling proteins and stop her being hungry. We might even drop her chronically elevated insulin levels. She would lose a ton of weight, give all of her food to her daughter and die of a starvation related illness herself. Injectable altruism...

Looking at multiple studies where adipocyte insulin resistance has occurred under ad libitum conditions certainly demonstrates how metabolism breaks under free access to insulogenic calories. I can't see how it refutes the role of insulin in obesity. It utterly destroys a straw man, but you have to actually do some thinking to understand what is going on.

It's all genetic:

Twenty monogenetic obesity syndromes! All in leptin signalling! Unfortunately a) That hasn't given us 20 solutions to help the 200 million overweight and obese people in the USA. and b) In the last 30 years fat people must have instigated a covert "fatties only" breeding program. Think of orgies where skinny people get castrated by fatties as part of BDSM games. We all know it's happening and there is a government cover up. From about the 1970s onwards.

Ultimately life is genetic and if there wasn't variation in response to insult there would be limited ability to select for surviving that insult.

If you want to REALLY look at what a blind alley the genetics of obesity are leading you up just try ref 35 from Stephan. Same genes in Mexican Pima and USA Pima. Only the USA Pima are fed on "D12451" and look like ob/ob mice. Mexican Pima eat Mexican food and blend in to the population. I looks like my BDSM hypothesis on generation of the obesity epidemic might be incorrect. Ah well, back to the drawing board.

Let's look at the natives:

Starch based diets are not associated with obesity. They do not cause hyperinsulinaemia, post prandial or fasting. They do not cause insulin resistance. You can, with significant effort, become obese on starch but only if you force yourself to do so.

I agree with this, in unacculturated people.

I think it might even have applied to people in the USA of 1900.

I disagree with this if applied to the current industrialised world, especially anyone who has become obese. Why should this be?

Obesity was present at a low level in the USA of the 1900s. Rumour, without hard data that I can locate, suggests it affected less than 1% of the population. It increased slowly until the 1970s by which time it was present in around 15% of the population. From 1970 to 2000 it doubled to 30%.

There's a graph on wiki here.

We know form Stephan's neat graph that this gradual rise in obesity between 1900 and 1970 was associated with a fall in carbohydrate consumption and that the rise in obesity after 1970 was associated with a rise in simple sugar consumption.

If you were to include a separate line to show sucrose (plus, as it became available, HFCS) it would rather neatly parallel the obesity curve. Obviously no one wishing to discredit Gary Taubes would do this but, if you are interested in hyperinsulinaemia as a cause rather than a consequence of obesity, I would suggest that you might be rather interested in this line. Once you are insulin resistant carbohydrates become spontaneously fattening. No ritual needed, it happens very much against your will.

The body uses fructose to replenish liver glycogen. There, I said it. The occasional bit of fruit will not make you obese. You only convert fructose in to a fatty liver through denovo lipogenesis when intake is in excess of what humans are remotely able to make use of. Elite athletes consume rather a lot of fructose. It helps them win races. Try breaking your leg by falling off your pushbike and then still keep up the cola consumption needed to keep you in the yellow jersey... You may just develop a fatty liver. OK, you will.

With a sucrose content in the diet averaging 64 lb/year very few people would start on that journey to hepatic denovo lipogenesis in the USA of 1900. At 120 lb/y over a third of the population will go that route. Once you have accepted that dietary fat causes obesity you are then going to eat the replacement carbohydrate which will dial up your fasting insulin and hunger. Official fat phobia kicked in during the 1970s...

Oops, I forgot that insulin is a satiety hormone and facilitates weight loss and a low insulin level will make you hungry. That good old low carbohydrate paradox.

There is a rather stupid saying that "you are what you eat". It is slightly better phrased as "you are what you do with what you eat". You could go so far as to say "You are what your food does to you". I won't go in to epigenetics except to say that you can think about the phrase "You are what the food eaten by your mother and granny did to you". Certainly to your X chromosome(s) and your mitochondria.

In 1900 very few people had grannies who consumed even 64 lb/year of sucrose. More likely less than 30 lb/year. I remember dipping white bread toast spread with margarine and marmalade in to tea sweetened with three heaped spoonfuls of sugar at my granny's house in Bargeddie on the outskirts of Glasgow. And being amazed at how she could actually bring herself to inject her own leg every day with insulin. This was back in the 1960s, I'd have been about 5 years old.

If you are overweight and try going on a starch based spontaneously hypocaloric diet you may as well sign up for Barndard's disastrous diabetes diet. If you are far enough in to metabolic syndrome to find the label "diabetic" has been applied to yourself, going to a high carbohydrate diet will ruin you blood glucose control as soon as you stop losing weight. No one can lose weight for ever.

I was going to say that no one is going back to Kitava from modern Texas but this clearly depends on how permanent the damage done to you metabolism is. The more damaged you are, the more carbohydrate restriction is likely to benefit you long term.

As I read through this post there are two things which come to mind. First is that elevated insulin is core to weight gain. Second is that we have to be very careful about exactly what, under which circumstances, elevates insulin. Discarding insulin as a factor in obesity because there are circumstances in which starch does nor invariably elevate insulin is a serious case of throwing the baby out with the bath water. There are circumstances in which carbohydrate does not elevate insulin. Most of us don't live there, we can tell by our waist lines.

This post has been a long time coming. I've not particularly enjoyed writing it. But I have an insulocentric bias about obesity and its host of associated medical problems. Insulin provides a framework which, so far, paints a consistent picture of the way life works. It has served me pretty well.

Time to hit "post"

Peter

Latest obesity paradox...

2011-08-22T20:43:00.006Z

Just took a break from reading about the destruction of the carbohydrate hypothesis when this scandalous tidbit popped up:

I might have ignored it (it's from the days when the USA was not quite so gravitationally challenged) and just had a private giggle until another, more current, view of American Cuisine from the outside popped up through Stan's site link to Gonzalo Lira.

It just goes to show that high reward food does not have to taste of anything, or perhaps obese people should stop eating their cardboard menus and limit themselves to the Food-shaped-product on their plates to simply lose all interest in eating....

Problem solved.

Peter

If there were time...

2011-08-05T05:15:00.006Z

Well, being back online is one thing. Having the time to actually do any posting appears to be quite another... At the moment I'm actually sleeping until 6am, well after the time I'm usually writing posts. Life is exceedingly busy with life type things, especially the house, garden, work and emergency patching up of our elderly Miata. As life settles down I'll get back to posting again but for the next few weeks it's just not a practical proposition!

Thanks to all for the comments about the family on the last post and for links emailed.

Peter

Back on line

2011-07-24T06:43:00.005Z

OK, BT have set up a string and two tin cans to our village and Virgin Media are providing copper wire broadband, which is reasonably fast. So we're back on line.

It's time to start vegetables in excess of the onions and tomatoes in the beef mince on to which our daughter is rapidly weaning herself. After a false start with simple vegicide (Q. How much broccoli can a 7 month old baby hold in her mouth before spitting the whole lot out in disgust? A. Quite a lot) we tried the cocoa bean.

This has been somewhat more successful at 74% of solids plus a little sucrose:

And this is her big brother, end result of feeding as much saturated fat as practical to someone who, embarrassingly, actually loves fruit and broccoli!

Peter

BTW, we have also unpacked the scales. I haven't weighed myself for nearly a year and appear to have dropped from around 64kg to just below 63kg. That BMI is below 20. Time for some overeating methinks!

Here we go again

2011-07-07T20:52:00.001Z

The plan for tomorrow is not blogging, many posts that there are in the wings:

Peter

Diabetic and hungry?

2011-06-24T05:14:00.006Z

EDIT from later in the day. I put this comment up on Stan's blog after reading the full text:

Stan, I think we have to note that weight gain post study was almost a kilo a week (average gain 3.1kg in the first month post study) and three patients were clinically diabetic again by this time (a quarter of the participants). Long term there is no hope for any of them unless they keep themselves so hungry as to have a low carbohydrate intake while ever they eat a "balanced diet". Some might do it, the Iron Few... Most cannot live with this sort of hunger. The fact that the rise in insulin was statistically ns should not blind us to the fact this is a product of small numbers and the routine wide SD in plasma insulin levels. The p < 0.05 fall in FFAs says insulin is physiologically elevated and easily explains the weight gain.

And predicts catastrophe.

Peter

END EDIT

House move time again. Glasgow house is sold, time to buy in Norfolk. Not sure how much blogging will be happening and we're moving to a non broadband area. Dial-up here we come, but there will be a garden with room for chickens!

This one will be fun when the full text becomes available. At 600kcal/d this is a low carbohydrate diet in anyone's book. A low protein diet, a low fat diet, it has it all...

My immediate reaction is to ask what a type 2 diabetic of initial BMI 23 would look like after eight weeks on 600kcal/d! Dead skinny? Skinny dead?

Of course even if the diet was 50% carbohydrate it would only be 66g/d of carbohydrate per day. Some one should tell these folks they can do as well on this level of carbohydrate restriction without all of that nasty hunger if they ate some decent fat and protein along side their carbohydrate restriction.

Peter

From the Sky article:

Retired lorry driver Gordon Parmley, from Stocksfield in Northumberland, spent four years on daily medication for type 2 diabetes despite being only 2st overweight.

[and if he had not been overweight at all?????]

The diet worked and 18 months later he is still free of diabetes and does not have to take any tablets.

"It was very tough. I was hungry all the time. It was a starvation diet and food was on your mind all the time," he said.

Mice and breast cancer

2011-06-17T05:50:00.011Z

Laura and Elizabeth (thanks for full text) both forwarded links to this study.

Low carb diets, in the correct mouse model, delay onset and slow progression of breast cancer.

It says the sorts of things you would expect it to say and, if you really feel this highly artificial mouse model has relevance to the sorts of breast cancer humans might develop, it certainly suggests that a low carbohydrate diet might have some benefits. But the paper itself is awful.

Two giggles did come out of it. First was the use of high percentage of casein as the sole protein source. Now somewhere, sometime, there was a vegan nut who screamed that casein was carcinogenic. China? China Syndrome? China Study? T. Colon Campbell???? Shrug. These has-been vegans get everywhere.

The second is the extreme fat phobia of the authors. I know these people have to make a crust and funding is not what it used to be and fat bashing is always helpful but there eventually comes a point when people really believe that fat causes cancer. Even highly saturated milk fat.

You can just imagine that cows evolved casein and palmitic acid to kill their calves. Or humans are not mammals in the same way as cows are, human breasts having evolved to sell newspapers rather than to feed offspring. Human babies should be fed sucrose water with a little soya bean oil added of course. It's a strange world.

I have reached the point where I no longer give any credence to high fat diet studies where 30% of the calories are coming from sucrose or the pellets are stained red to signify Crisco. Not so the current authors.

Ultimately, while sucrose and trans fats are excellent substances to study when looking at the effects of pushing the profitability of the food industry to its absolute maximum, they have nothing to do with a high fat diet based on Food.

Reading through the full text there are so many failures of perception and basic biochemistry that it might be worth a post in the end, but here's a typical blooper. Not only do we have Gourmand rats, we also have mice who need false teeth!

First we have to have another black box warning

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Untested ad hoc hypotheses can make you look very stupid.

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Here we go:

"Although mice on 8% CHO diet had slower growing tumors, they lost weight, weighing, on average, 20% less than mice on 5058 diet (Fig. 1D). This was consistent with the mice eating less than the 5058 group (data not shown), likely because the 8% CHO pellets were significantly harder to chew."

Executive summary: We're idiots.

Extended translation:

Diet 5058 is standard breeding colony crap-in-a-bag with 55% of calories from starch. It appears to be mildly obesogenic compared to 8% of calories from starch... That MUST be because the lower carb diet is too hard to chew. We couldn't be arsed to have a control group offered a harder diet with 55% carbs because we're idiots, as are our scrutineers.

GCBC anyone?

Oh, and another giggle: 5058 is described, COMPLETELY incorrectly, as a "Western Diet". It's a starch based, sucrose free, 20% fat, mostly PUFA, trans free diet, remarkably similar to Barnard's idiotic vegan diet for the progression of diabetes in humans. It's standard mouse chow.

Where do funding bodies find these people to throw their money at?

Eeeh, yer has ter larph.

Peter

When is a high carbohydrate diet not a high carbohydrate diet? Ask a vegan?

2011-06-13T19:58:00.013Z

There is a study, headed by Barnard (of PCRM infamy), purported to show the benefits of a low fat vegan diet for the management of type two diabetes in humans. This is, obviously, counter intuitive. So let's have a look.

The first thing to say is that it's extremely difficult to extract any hard data from the study. Many of the results are expressed as derived from "intention to treat" analysis. To appreciate quite how difficult this makes any sort of deconstruction, you have to read Dr Eades on this subject. Much of the HbA1c data are presented as the value before any medication change occurred. A change could be up or down (both occurred) and could have occurred after one week or after 73 weeks on the diet. The HbA1c value from just before the change in medication gets carried forward throughout the rest of the graph of HbA1c that features in the discussion, see later.

But let's take the study at face value. I'll begin with the top section of Table 2.

Now you may be forgiven for skipping down to the carbohydrate intake line where the massive increase from 47.7% to 66.3% is noted. This would be a mistake. First line to note is the SPONTANEOUS drop in caloric intake noted in the vegan group. 1798kcal/d to 1366kcal/d. This compares with the ENFORCED caloric restriction on the ADA diet, which did not alter the macronutrient ratio in any way from the pre study diet. This is where Stephan found the study interesting. I have a couple of concerns about the explanation of the vegan diet providing limited reward which I would need to see addressed before going along these lines:

No one sells a diabeso-genic diet for rats based on starch. There are two main techniques for making rats fat and glucose intolerant. The first is sucrose, the second is Crisco. You can also do it with lard, but that's a rat oddity and I doubt it applies to humans, as far as I can see.

The vegans reduced their caloric intake percentage of trans fats from 2.3% of calories to 1.1% of calories. The ADA dieters didn't. p < 0.0001.

If you want to look at either total fructose or HFCS or table sugar intake comparison between the two groups I'm afraid you will have to ask Barnard for this information, it's not in the paper. But I think it's safe to assume the vegan diet included the advice to consume minimal sucrose/HFCS and the ADA, with it's role in promoting diabetes to maintain medication sales, had some. Possibly quite a lot. Who knows? Well of course, as I said, Barnard knows; but he's not saying. Let's just assume p < 0.0001 again.

I would want these two factors to be controlled for before I would become interested in looking at food reward effects of the relative diets, important though this might be.

You may have noticed that the concept of components described as "a percentage of calories" has already sneaked in.

So next we have to look at that % of calories from carbohydrate expressed as a number of grams per day of carbohydrate, especially on that vegan "high carbohydrate" intervention.

Pre study the vegans were eating 47.7% of 1798kcal as carbohydrate, ie 858kcal or 191g/d. By week 74 of the study they were eating 906kcal/d or 201g/d of carbohydrate (66.3% of 1366kcal).

So the total carbohydrate intake increased by 10g/d. Did you notice that on initial browsing of Table 2? Tee hee.

Two other factors have to go in. Fibre, included in total carbohydrate, increased from 10.8g/d to 21.7g. Most of this was insoluble fibre, ie it literally became vegan cr*p. You know, wipe, flush... Let's see, 201g-11g=190g! Wow!!! I couldn't have asked for the arithmetic to work out that neatly, just a happy coincidence. Made me laugh anyway.

So, is this a high carbohyrdate diet, compared to the SAD? No. NO.

Weight loss. For the later months of the study subjects were weight stable. During this phase the vegans and ADA dieters deteriorate at remarkably similar rates. During the initial few months, when both groups demonstrated a very small improvement in HbA1c, there will have been marked weight loss. We don't know what the calorie intake was during this phase. If it was less than 1366kcal per day with a similar % of calories from carbohydrate this might actually have been a carbohydrate restricted diet!

If we briefly scan the HbA1c graph

it is pretty obvious that the ADA dieters stopped losing weight at 11 weeks and the vegans stopped losing weight at 22wks. End of weight loss is the time at which you would expect HbA1c to stop dropping and metabolic deterioration to set in for both arms of the study. Please note that we have no idea how many patients at a given time point are providing true HbA1c values or how many data points include "carried forward" values before a medication "change". Over 74 weeks 17 vegans actually reduced their meds by an unspecified amount and 10 increased them, again by an unspecified amount. So 17 out of 49 subjects provided "hypothetical" HbA1c values for some unspecified amount of the study period. Go figure. Must have been written by a low fat vegan!

I would be willing to bet that the 17 vegans reducing their meds were all "carried forward" from the first 22 weeks and the 10 increasing their meds were in the >22 week period... You don't generally increase meds in type 2 diabetics during weight loss.

You can't lose weight for ever.

Once weight loss stops and human adipose tissue consumption ceases we are back to starch for diabetics and progressive HbA1c deterioration.

What would you expect?

It is quite clear that healthy humans can consume a very wide range of macro nutrient ratios. If you are glucose intolerant you cannot. Are you glucose tolerant? Are you sure? Russian roulette?

In summary: Any person with diabetes who considers that dropping their HbA1c from 8.05% to 7.71% (intention to treat basis) by following 74 weeks of low fat veganism will help them, is deluded. If they think it is going to get them out of the queue for dialysis, they're wrong. I suppose that weighing 4.4kg less in the dialysis room might give you a better self image, but this benefit might be wasted if you are blind by that stage...

Peter

A couple of add-ons:

Dr Haimoto in Japan produced this result by simply restricting carbohydrate to 137g/d of which 14g was fibre. The study was not intended to cause weight loss and it didn't, what there was was non significant. So this improvement in HbA1c is WITHOUT weight loss. Neat hey? Better end-study HbA1c values would need lower total carbohydrate intake.

Of course Dr Haimoto gives us all of the individual HbA1c plots and of course the individual weight change data. No intention to treat here, just numbers, including the data from the non compliers.

Then we shouldn't forget the Nielsen and Joensson study in Sweden

These people were asked to lose weight (not spontaneous). Note that maximum fall in HbA1c was at the time of max weight loss which occurred at the time of maximum compliance, here are the individual weight loss plots. No intention to treat fudge. Carbohydrate limit was recommended to be at 80-90g/d but some carb creep was noted... Despite this, note the downward trend in HbA1c over the years. Sorry there was no room to extend the graph to the full 44 months.

Oh, and for chopping off the top of the last graph!

PharmAmorin

2011-06-04T08:10:00.004Z

Got a brief look around the net this morning. I see Tom Naughton has skipped his meds again.

If the enforcement order isn't working it's clearly time to speed up the inclusion of PharmAmorin in his (and everyone else's) tap water supply.

Peter

Energy expenditure in obese vs slim non dieters

2011-05-30T07:39:00.008Z

Just before I get back to the prolonged fasting and weight loss post I thought I'd put this picture up.

It's slightly modified for clarity and taken from Fig 1 of this paper.

None of the 10 people in either column are being dieted, the graphs would be different under caloric restriction. I would, all things being equal (ie a linear relationship from thin through obese to a BMI of 50), expect the obese subjects to use/lose more adipose calories per day in proportion to their obesity if you suddenly withdrew all food.

They don't.

There's more on the study here, which has all of Fig 1 and has not been subjected to my activity with a rubber (OK, an eraser if that's less risque).

Peter

Cholesterol and Carruthers

2011-05-29T10:57:00.005Z

From The Western Way of Death, Malcolm Carruthers, p20-21, 1974 (back when I worked for the East Midland Electricity Board as a COBOL programmer. Boy, were they glad when I left to go to vet school!) Carruthers:

Even when heart attacks started to become a fashionable way of death at and increasingly early age, progress towards discovering their causes still lagged. This was partly because scientific theories naturally tend to be partly based on what has been most recently observed and can be most easily measured. Cholesterol was the ideal choice of culprit as it had been found on the scene of the crime by microscopists. Its footprints in the shape of characteristic clefts could be clearly seen in the walls of some of the affected arteries, where it could be stained a spectacular and guilt-ridden red colour. The chemists were also happy to testify to cholesterol being the "bad egg". There was plenty of it to measure, both in the blood and in the food, and the levels of the two and heart disease tended to bear a suspicious, albeit inconstant relationship. Being nice and stable both in and out of the body, and not one of those will-o'-the-wisp compounds whose blood levels vary wildly during the day and disappear as soon as you think you've got them trapped in a test tube, it was a sitting duck for the collection of chemically incriminating evidence. From here it was a brief exercise in ad hoc reasoning to the "It's what you eat that does it" school of thought that holds sway to this day. This originally suggested that a high cholesterol diet raises blood cholesterol to a level where it is gradually deposited in the walls of the blood vessels and builds up to cause atheroma. For various reasons, this theory was later broadened to include saturated animal fat among the dietary "baddies" in the dock along with cholesterol. Unsaturated vegetable fats, especially the polyunsaturated ones, were cast in the role of "goodies" who were able to combat the evil effects of the "baddies" [note, this was written well before the StarWars movies were released, prescient hey? No mention of The Force though]. The market soon became saturated with unsaturated food products. This was good for the circulation of grocery products and magazines with complicated diet sheets, but appeared to have little effect on the coronary circulation. Heart attack rates obstinately continued to rise.

Peter

Surwit and sucrose or when is a high sucrose diet a high fat diet?

2011-05-29T06:42:00.007Z

Last one liner post and I'll try and get to older comments as soon as I can:

The name Surwit is familiar. I have this niggling feeling that I've come across it before. There's no inclusion of the name on the blog except as the name for an obesogenic mouse diet based on sucrose. I have this feeling it was someone pointing out that a high sucrose diet was perfectly acceptable if you kept PUFA low. Can't find it. Don Matesz brought the paper to light recently by discussing it over at Primal Wisdom. It's a core paper on why you should be cautious about simply accepting conclusions from papers without thinking them through.

I just wanted to pour a little arithmetic on Surwit's paper from 1997.

The 1100kcal diet was 70% carbohydrate, ie 770kcal/d or approx 180g/d.

Protein was held at about 50g/d and fat was held at around 10g/d

Let's look at calories-in and calories-out.

With a weight loss of 7kg in 6 weeks these people were augmenting their diet calories-in by adding an additional 167g/ day of fat from their own adipose tissue (assuming weight loss is fat loss, not quite true). This gives an average "calories-in" of 1100kcal from diet plus about 1670kcal/d from adipose tissue, ie a total of 2670kcal per day going in to metabolism.

Calories-in of 10g fat from the diet plus 167g/d of fat from adipose tissue, with a total of 2670kcal per day used, gives us a metabolic input comprised of 66% from FAT.

120g/d of sucrose is about 540kcal/d which actually makes this only about 20% of the "calories-in" to metabolism, with fructose at about 10% of calories.

The study subjects are obese which, trans fats apart, suggests that they are probably eating a great deal more sucrose per day during their habitual diet than 120g (and failing to deal with it effectively). So, in comparison to their pre study diet, this is probably a LOW SUCROSE diet. A Big Gulp is about 800kcal per serving of HFCS... At 180g/d the study diet is also a LOW CARBOHYDRATE diet compared to their pre study intake. You do not "accidentally" maintain a bodyweight up near 200% of ideal unless you have a carbohydrate intake waaaaay in excess of 180g/d. Just flick through the introduction to Grey and Kipnis yet again. Obese people eat more calories and especially more carbohydrate calories than normal weight people.

Now, let's stop weight loss occurring and think about health on a 34% sucrose diet. Let's up the calories-in from 1100kcal/d to 2670kcal/d to (possibly) maintain a stable weight (it won't happen, weight will rise secondary to increase insulin levels associated with a fall in spontaneous activity) but this time let's source all of those calories from the diet. With 34% of calories as sucrose that will be just under 300g/d of sucrose. That gives an annual intake of just over 100kg, about a tonne in 10 years. HDL is already down from 1.35mmol/l to 1.06mmol/l (if you think it matters) and if you think trigs will stay at just over 1.00mmol/l on a third of a kilo of sucrose a day you are incorrect. Will the drop in blood pressure be maintained? Hahahahahahaha. Do you want to try this?

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BLACK BOX HEALTH WARNING: The next line is sarcasm.
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I'm sure it would be fine, just ask Surwit.

You can't lose weight for ever. Weight loss is fat metabolism. When weight stabilises how do you maintain the benefits of fat metabolism? Hint: Don't replace it with sucrose.

Peter

MGmin-LDL

2011-05-28T21:27:00.003Z

I think Liz, Dexter and THINCS where first in with this study.

Can't find it in Pubmed yet but I've got the pdf.

OK, first there was TC, then LDL, then sdLDL, then oxLDL, now MGmin-LDL and there was another LDL somewhere along the line, I've forgotten which it was... I really can't keep track.

Never forget psLDL (purple spotted, hint: It's made of sugar).

Peter

Nissen on Niaspan

2011-05-28T21:06:00.005Z

I'm assuming everyone knows that Niaspan has recently bombed as a supplement to a statin. There's a nice summary here.

Let's set out the Hyperlipid view. HDL is a surrogate for saturated fat consumption. Elevating HDL with a drug will not give the benefits of saturated fat consumption. Triglycerides are a surrogate for sugar consumption. Dropping their level with a drug will not improve health, only putting the sugar in a bin will do that...

Anyway, this one liner post is dedicated to Dr Rentaquote Nissen. From the above link:

"Niacin does all the things that doctors would expect to benefit patients, such as lowering bad cholesterol and triglycerides while raising good cholesterol" said Nissen, who prescribes it for his patients.

“This was the group everybody thought had the best chance at a benefit,” he said today in a telephone interview. “At this point, we have to take a deep breath and realize we’re not as smart as we thought we were.”

Nissen's mistake was to think he was smart in the first place. Big mistake. The glimmer of light is that he might realise he's been an idiot.

Peter

Anger vs diet in Japan

2011-05-28T20:31:00.008Z

Apologies for not getting to reply to emails and to the comments from the last post, several will take some time and there are a few one liner posts to throw out in the mean time. This is one.

I've been following the events at Fukushima with some interest, particularly as we live about 15 miles from Sizewell B, the UK's only commercial pressurised water reactor. One of those I've browsed is this one from the NY Times on the subject of the effect of the disaster on the populace of Fukushima city, where anger at the government's handling of the situation is becoming quite extreme.

"A huge outcry is erupting in Fukushima over what parents say is a blatant government failure to protect their children from dangerous levels of radiation. The issue has prompted unusually direct confrontations in this conflict-averse society, and has quickly become a focal point for anger over Japan’s handling of the accident at the nearby Fukushima Daiichi nuclear power plant, ravaged in the March 11 earthquake and tsunami."

Conflict-averse society is an interesting phrase, certainly to me, as I have just started to re-read Malcolm Carruther's book "The Western Way of Death". I read it as a 20ish year old bloke and stopped fitting half-race cam shafts to the engines of assorted Morris Minors and switched to a Volvo when I got the chance. The current MX5 I drive was not my idea and I still try to follow the advice to use a driver's seat as a mobile arm chair.

Carruthers is highly entertaining in his approach to the cholesterol hypothesis of CVD (it's bollocks, I paraphrase loosely). He focuses on the emotional and catecholamine triggers for heart disease, far more in keeping with a hyperlipid point of view. Adrenaline releases glucose and FFAs at the same time, a bad mix if you are sedentary, okay if you are legging it up a tree when you accidentally almost walk in to a white rhino in the Hluhluwe-Imfolozi game reserve. A foot safari is great...

To get back to the concept that Japan is a "conflict-averse society" and Carruthers' hypothesis that aggression, greed and ambition are major drivers of CVD. You have to decide whether the appalling rice based diet of the Japanese is responsible for their apparently low rate of CVD or whether is it their reluctance to indulge in conflict within a highly structured society which provides the CVD protection. A conflict-averse society...

This links straight back to Marmot's paper, based on his PhD thesis, where Japanese emigrants who maintained a Japanese lifestyle but who adopted the SAD of the 1950s were markedly protected against heart disease. Especially compared to those who behaved as Americans but still ate the traditional Japanese diet. Here is the figure which matters

A detailed explanation is here.

This brings to mind the potential for marked injury to the residents of Fukushima, to the point where the injury from anger might outweigh any potential benefits from the hormetic effect of a modest increase in exposure to ionising radiation.

Anger is bad for you.

Fukushima is an angry city. This is far more worrying than the increase in ionising radiation exposure.

Peter

Fasting insulin and weight loss on a water fast

2011-05-19T21:20:00.034Z

I think we have to be very careful with the term fasting insulin.

If we read, in a clinical paper, that fasting insulin level was X iu/ml it is perfectly reasonable to assume that this level simply reflects the carbohydrate content of the diet over the two or three days in the lead up to the blood draw. You only have to look at Grey and Kipnis' paper to see that, independent of weight change, fasting insulin can be simply dialed by adjusting the macronutrient ratio. It can be dropped from 40 microIU/ml to 10microIU/ml and cranked back up to just over 50microIU/ml, each shift occurring over a few days:

If we go to a rather better conducted study we can look at the effect of starvation on fasting insulin levels. What happens if you live on water for 5-6 weeks? Well, I guess it's obvious that body weight drops. Here are the clinical data for the eleven volunteers:

I worked out the average weights at the start and end of the study. The drop was from 135.8kg to 115.6kg, something in the region of 20kg of body weight. Obviously some of this would be glycogen, glycogen-water and muscle, but a big chunk must be fat.

What happens to fasting insulin?

Well, there are three different "fasting" insulins on this graph. The first is 45microIU/ml. This is the fasting insulin on the normal diet of an obese person. Second is about 38microIU/ml, after restriction of carbohydrate to 300g/d with caloric intake at 2500kcal/d. The third is between 20 and 14microIU/ml, achieved after three days total fasting and this level basically doesn't budge over the following 6 weeks, even though bodyweight drops by 20kg.

This later value is a great deal higher than a non obese person would have under prolonged fasting conditions and remember that the people in this study are preselected as having failed on every diet they have ever tried and they are willing to undergo the risks of a prolonged water fast. They do not appear to be hyperinsulinaemic as a consequence of their excess weight if a 20kg acute weight loss has no effect on blood insulin levels.

The blood glucose normalises within three days of the start of fasting. At this point physiology's role is to control hepatic glucose output. All tissues which use glucose via insulin should have stopped accepting glucose to spare it for the brain.

In these people the level of insulin required to do this in the region of 10 times that of a spontaneously slim person.

Obviously, if you perform a cross sectional observational study of fasting insulin vs bodyweight there will be a positive correlation between the two variables. It is a perfectly valid hypothesis to propose that obesity CAUSES hyperinsulinaemia. Equally, if you are as stuck in the rut of fasting insulin inhibiting inter-meal lipolysis as I am, it would be perfectly reasonable to hypothesise that people with the highest fasting insulin are the fattest because hyperinsulinaemia CAUSES obesity. Both are potentially valid explanations of the observation.

Who would lose weight fastest on a water fast?

Calories in, calories out... Obviously calories-in during starvation is solely supplied by lipolysis and protein breakdown, once glycogen is depleted. With a BMI of 50kg/m2 "calories-in" from fat breakdown are essentially unlimited, if they happen to be metabolically available. So weight loss should be determined by basal metabolic rate plus exercise/spontaneous movement. A fat person should have a slightly higher basal metabolic rate just to run the support tissue for moving their fat around, even if the fat itself has a relatively low metabolic rate. You must also remember that an overweight person is like me doing a squat with 60kg on my back every time they sit down and get back up again from a chair. So on both of these counts you would expect the fattest people to have highest "calories-out" and so lose weight more rapidly than less obese people.

They don't.

I data trawled and carefully selected choice points from table 1, discarding the half which don't fit the line. I used the blokes only. All is forgiven Dr Keys. Plotting weight loss against starting weight gives a crude (negative) correlation for men. Let me be the first to admit that the relationship does not hold if you include the female subjects. Life would have been easier if we had been given individual starvation insulin levels, rather than having to take bodyweight as a rather crude surrogate. The three women outliers who ruin the plot are, interestingly, short stature.

Here's the plot for the men:

On a water fast the higher your starting weight (surrogate for "fed" fasting insulin, remote surrogate for "starvation" fasting insulin), the less weight you lose over 5-6 weeks.

Elevated insulin is associated with obesity BECAUSE it inhibits lipolysis.

Maybe there are other explanations. I just can't see them. None as blind as...

Peter

Of course addressing what causes elevated fasting insulin and why it doesn't normalise on prolonged fasting is a whole new ball game. People should look in to it. Carbohydrate restriction obviously gets you part way to sorting the problem. It side steps it rather than curing it. I have said this before.

LIRKO mice (2)

2011-05-15T09:57:00.008Z

This post is a bit rushed so apologies for typos/grammar, but there is a just usable swell and low tide in First Bay is in just over an hour's time so the 'yak is on the car... Just need the Baba to wake up and we're off.

Here are the facts and figures for LIRKO mice from this paper:

OK, they really are slim, they have about 10% less bodyfat than control mice. Here are some of the biochemical details:

The LIRKO mouse has a leptin level which is 10 times that of a control mouse, despite having 10% less bodyfat, that's graph A. Does this mean it's fooling its brain in to thinking it is obese? Probably not, Graph B shows that LIRKO mice have almost infinitely more sOb-R in their blood. This is a binding protein for leptin, bound leptin is biologically inactive. In graph C we can see that free leptin per unit fat mass is actually very low.

Graphs D, E and F show hat happens when you infuse leptin or saline intravenously for 30 minutes. Note the log scales. Graph D shows it is possible to get leptin to equally astronomical levels in LIRKO or normal mice. Graph E shows that the leptin binding protein, sOb-R, doesn't change in the LIRKO mice but falls non significantly in normal mice on leptin infusion. Graph F shows that the free leptin index goes up significantly more for control mice than for LIRKO mice. ie the control mice should feel less hungry and so eat less

But that's not what happens. Four days of leptin injections drops appetite and weight more in LIRKO mice than in control mice. Despite the appetite suppressing free leptin index being higher in the controls.

This appears to happen because the brain of a LIRKO mouse is more leptin sensitive than that of a control mouse:

SOCS3 mRNA level is something I've not read about but I'm willing to accept that it is a marker of hypothalamic leptin resistance.

Does any of this mean anything? Yes.

The LIRKO mice have no hepatic insulin sensitivity because of a very specific genetic defect which deletes their liver insulin receptors.

The liver does not know this. As far as it is concerned the pancreas is simply not secreting any insulin, ie there is no food being eaten. There may be a ton of glucose floating past but, as far as the liver is concerned, there is none.

Are there any other conditions which mimic this and might also spike sOb-R? The paper cites three. Type 1 diabetes. Here there is a ton of glucose but zero insulin. Total insulin deficiency is "hepatically" indistinguishable from the LIRKO liver not seeing any of the insulin (or glucose) raging through the bloodstream. Low insulin in T1 diabetes. High sOb-R.

Anorexia nervosa produces a genuine combined insulin and caloric deficiency with a high level of sOb-R. Low insulin. High sOb-R.

Ditto a 72 hour fast in men. Low insulin. High sOb-R.

How about ketogenic dieting? Here too there is low insulin. Will blood leptin binding increase? Hypothalmic leptin sensitivity increase? Appetite be normal? While ketogenic dieted mice do not particularly drop their caloric intake they do, like type 1 diabetics, fail to increase their caloric intake to meet on going caloric output (they become warm rather than glycosuric as their caloric "sink")...

Now, where does the letpin binding sOb-R come from? The liver is the source in LIRKO mice. The LIRKO mice have liver cells which are in a starvation situation. They manipulate leptin binding and availability to keep appetite normal.

What controls sOb-R production in normal liver cells?

Insulin.

If you put normal liver cells in a petridish with insulin they reduce production of mRNA for the short leptin receptor gene which produces one of the sOb-Rs. Under zero insulin the mRNA level for the Ob-Ra gene is 5 times higher than under 0.1micromol of insulin. Leptin itself has some suppressive effect, but insulin is the dominant hormone.

This looks very much like the liver has a mechanism for controlling leptin sensitivity.

Insulin. Hmmmmmm

As a complete aside: The other potential mechanism for the decreased appetite is insulin per se. Now, we are all fully aware that insulin is anorexic agent. All you have to do is inject a little insulin in to your brain and you will decrease your appetite. This is logical, after a meal you have a high insulin level and shouldn't want to eat.

Under fasting conditions you have low insulin levels and should want to eat. It's likely to keep you alive. Simple.

So, to stop people being hungry, all we need is to inject insulin in to their brain. Overweight? There's the queue...

For those of us who wish to lose weight without that intra cerebral injection we could try mainlining insulin. This may or may not suppress appetite. I've never tried it. Certainly none of my hyperglycaemic patients seem hungry when I inject them with insulin by the subcutaneous route. Until their blood glucose level drops below about 6mmol/l that is.

At that point they will eat ANYTHING. And lick the bowl. I'm not sure if they feel guilty afterwards. None of them seem to go and make themselves vomit in private to stay slim. Difficult to hide the evidence in a ward cage!

But the LIRKO mouse, with insulin levels 8-20 times those of a control mouse, never becomes hypoglycaemic. It's ONLY hyperinsulinaemic BECAUSE it can't mop up dietary glucose.

So perhaps we are actually seeing the anorexic effect of insulin in this mouse model. The levels might be high enough. The paper wasn't set up to look at this, but it's an interesting afterthought. Back to leptin.

Finally, how does the hepatic insulin resistance of a LIRKO mouse compare to the hepatic insulin resistance of a sucrose fed mouse?

The sucrose mouse hepatocytes have insulin receptors. They can be made to respond. They prefer not to only because these hepatocytes are utterly stuffed with diet derived calories which they are converting to fat as fast as they can but can't export until insulin levels drop low enough to allow VLDL output. Which doesn't happen. Mmmm, Pâté de foie gras...

They are in a state of hypercaloric stuffedness, they see blood insulin and glucose and just don't want anything to do with either. Do they make a ton soluble of leptin binding receptor, sOb-R? No. In human obesity leptin is high, sOb-R is LOW and hypothalamic leptin resistance high.

Now, really finally, how does the LIRKO mouse type of liver insulin resistance compare to the hepatic insulin resistance of an extreme ketogenic fed mouse? It's exactly the same. Low insulin. So if you fed a LIRKO mouse an extreme ketogenic diet, would you "cure" its diabetes?

Probably yes.

If you based the ketogenic diet around butter rather than the almost pure PUFA in Mouse Diet 9F, would you prevent its cirrhosis? The liver is only getting its calories primarily from dietary fat after all.

Probably yes.

If you gave some LIRKO mice free choice of macronutrients ratio, would they put themselves on an extreme ketogenic diet to treat their diabetes? Of course they would. They're mice, they're not stupid.

Do I like the LIRKO mouse? Absolutely.

But the FIRKO mouse is even more interesting and paradoxical... Maybe another day.

Peter

LIRKO mice (1)

2011-05-15T06:47:00.005Z

I think we have to look at the LIRKO mouse. This fascinating beastie was brought to my attention by Chris Masterjohn and it's hard to know where to start with how amazing these animals are.

I suppose the first thing that grabbed me is that they are alive at all. They have no insulin receptors on their liver. None. You don't actually need insulin receptors on your liver to be alive... OK, they're pretty sick and go in to early liver failure, but they're definitely alive and reasonably functional at four months of age.

They have fed-state plasma insulin levels TWENTY times higher than those of control mice and fasting insulin levels eight times higher than controls. They are the ultimate model of hyperinsulinaemia.

They are, err, slim. Slimmer than control mice. Now that is cool!

So we have mice with massive levels of insulin. If you took an average mouse and injected enough insulin to peak its blood concentration at 20 times the physiological level it would rapidly become an ex mouse. It would be a late mouse. It would be no longer. But that's not what's happening.

These mice are eating CIAB and their liver wants nothing to do with the diet derived glucose. Nothing. The liver is utterly insulin resistant. No receptors, no response...

The mice eat Mouse Diet 9F which is 56.5% carbohydrate. Each mouthful of food pushes glucose toward the liver. The liver ignores it. Unharvested glucose hits the systemic circulation. The pancreas notices. The pancreas whispers insulin in to the portal vein and the liver ignores it. The pancreas speaks louder. The liver ignores it. The pancreas screams. The liver shrugs.

Where does the glucose go? With a blood glucose of 400mg/dl some goes down the loo (did I mention these mice were intensely diabetic? OK, they are intensely diabetic). The rest of the glucose tries its damnedest to get in to muscles. The muscles really don't want the glucose. They internalise their insulin receptors. Did I mention that these mice are intensely insulin resistant. OK, they are. Very. Whole body). The pancreas breeds extra beta cells then goes to the gym and pumps up those beta cells to steely muscled bulges of insulin hypersecreting islets. Insulin secretion goes up yet higher. It does no good. Not only do the beta cells multiply and hypertrophy, don't forget that the liver is the main sump for insulin degradation on a high carbohydrate diet. Not without insulin receptors it isn't. Hepatic insulin clearance is zero so insulin has almost nowhere to go. This too markedly contributes to the hyperinsulinaemia.

It would be interesting to see quite how high insulin would go if there was not the urinary route out for glucose... The bilateral nephrectomised LIRKO mouse. There's an interesting ICU challenge!

Does this massive hyperinsulinaemia inhibit lipolysis? Well, yes it does.

Interestingly FFAs are only reduced by about 40% compared to the control mice. But they are reduced. So why don't these mice become obese?

Ultimately they don't become obese because they cut calories. They are ad lib fed, they must cut calories because they're not hungry. Gasp.

Let's talk leptin. And insulin, of course.

Peter

Meat

2011-05-14T15:26:00.001Z

Vitro's Distort in the background.

Why low carbohydrate for diabetes (summary)

2011-05-09T19:43:00.011Z

If we look at the extremes of substrate source for the provision of bulk calories we have the choice of either fat or carbohydrate.

Under high carbohydrate intake we have high pancreatic insulin output and almost matched hepatic insulin extraction. Some insulin spills over in to the systemic circulation to facilitate bulk glucose utilisation but systemic hyperinsulinaemia and hyperglycaemia should be mild and within physiological limits (whatever they might actually be...). However there is a marked differential between portal vein insulin levels and systemic insulin levels, especially post prandially.

Under extreme ketogenic conditions energy is sourced almost exclusively from lipids. Insulin has minimal involvement with hepatic glucose uptake because almost zero hepatic glucose uptake is going on. Extreme hepatic insulin resistance leads to minimal extraction of what pittance of insulin the pancreas is producing and you end up with the minimal possible difference between portal vein insulin and systemic insulin concentrations.

What happens when someone needs to use insulin to maintain normal blood glucose levels?

If your only route in for exogenous insulin is via peripheral injection you can, with ketosis, put the body in to a state where insulin is relatively unimportant. You do not have to plan for one concentration of insulin to hit adipocytes and muscles while (impossibly) targeting a far higher concentration to hit the liver. Under ketogenic conditions the liver is no longer a sump for insulin usage. In fact there is almost no sump for insulin disposal as it's not being much used for anything. Peripheral and portal insulin requirements are similar and can be met by the peripheral route.

As you move from ketogenic eating to carbohydrate based eating the portal vein to systemic insulin difference has to increase and the problems of controlling hepatic glucose output while still allowing lipolysis to give access to adipose tissue calories becomes progressively more difficult.

It's notable that successful diabetes control, as promoted by people like Dr Bernstein, uses mildly ketogenic macronutrient ratios, ultra extreme ketosis does not appear to be needed. Humans are not mice.

Carbohydrate based diets would appear to lead to that wheelchair in the dialysis room and the incorrect impression that diabetes is an inexorably progressive condition.

Peter

Hepatic insulin resistance in KD fed mice

2011-05-02T06:38:00.005Z

Let's look this abstract. Thanks to Liz for the full text.

The key quote is, of course:

"In conclusion, despite preventing weight gain in mice, KD induces hepatic insulin resistance secondary to increased hepatic diacylglycerol content. Given the key role of nonalcoholic fatty liver disease in the development of type 2 diabetes and the widespread use of KD for the treatment of obesity, these results may have potentially important clinical implications."

I'm not sure what the word for a collection of idjuts is. A moronity?

Despite this the data are very interesting.

Look at those hepatic diglycerides, up 350%!!!!!!

Failure to suppress hepatic glucose output. Not just reduced, but reduced to zero percent suppression. Zero percent!

Wow, are these mice gonna die of diabetes, fatty liver, metabolic syndrome, Spawn of Satan induced inflamasomation.... Okay, I'll calm down now.

These mice are running their metabolism on a combination of free fatty acids and ketone bodies. What would you expect their liver to be full of? Sugar?

Glycogen?

Maybe fatty acids?

Well, in ketosis FFAs come from transport by albumin or release by lipoprotein lipase as exactly that, free fatty acids. They are not stored in this form, they are re-esterified to triglycerides for hepatic storage. The 350% increase in diglycerides is not from being swamped with diglycerides exogenously. They are generated in situ specifically to stop the liver responding to insulin.

These mice have no source of dietary glucose. They are generating and outputting small amounts of glucose from their liver, despite extreme protein restriction, to keep their blood glucose levels compatible with life. Possibly from glycerol.

Then some joker comes along with an insulin infusion. What would happen if their ability to trickle out glucose actually did suppress in response to this malevolent tease? Death would ensue in a few minutes without a rescue glucose infusion as is needed for the mice on CIAB. Hepatic diglycerides are generated to stop the liver responding to insulin when survival makes this an absolute necessity. It's an absolute necessity under extreme ketosis conditions, even without the joker with a bottle of insulin.

To get a breath of KetoSanity we can go back to the paper by Maratos-Flier's group (thanks to John for the heads up on this "non conformist").

These folks didn't look at diglycerides but they did measured the liver triglycerides and found they were nearly twice those of the mice fed crapinabag. Gasp! Fatty liver is where it's at. But these folks did a little histopathology too, using PAS to stain for glycogen. As they say:

"PAS staining showed decreased glycogen deposition in KD animals vs. both HF- and C-fed groups (data not shown)"

If your liver is glycogen depleted what, exactly, should it have as an energy store? Thin air? A small nuclear reactor?

Maratos-Flier et al understand exactly what is going on and see no need to trot out hysteria about ketosis generating a fatty liver which is physiological. It has nothing to do with fatty liver under a carbohydrate based diet.

Now, what would happen if we increased the carbohydrate content of the diet to 15% of calories in the same way as Axen and Axen did in their 2006 blooper?

Ketosis would stop and hepatic insulin sensitivity would return. Probably within three days and certainly within the three weeks A & A allowed. The diglycerides would be gone. Probably so would the bulk of the triglycerides. Under these conditions carbohydrate would clear the fatty liver.

Would the mice be diabetic? You've got to be joking.

So why does carbohydrate restriction improve fatty liver in humans? I would suggest the lack of de novo lipogenesis due to fructose reduction coupled with chronically lowered insulin allowing VLDL output to clear the excess of hepatic triglycerides. The situation is completely different.

I doubt many LC dieters would push themselves to the ultra extreme of the diet enjoyed by these KD consuming mice. If they did, their hepatic lipids, especially diglycerides, would have to increase to produce an utterly essential survival gift of hepatic insulin resistance. Their hepatic triglycerides would rise too.

I think it's an open question about whether placing yourself at the very extremes of physiology is a good or a bad thing. It should certainly assist weight loss, but would it improve health? Interesting question.

Peter

Prostate cancer paradox

2011-04-30T19:15:00.005Z

Many observational studies associate prostate cancer with markers of metabolic syndrome. Which gives us the omega3/trans fat paradox, well discussed in several places around the net.

Here's a similar prostate paradox.

How come these two exceptions buck the trend? Here's a random thought:

Let's assume prostate cancer is related to chronic hyperinsulinaemia, a reasonable idea, ie it is "metabolic syndrome of the prostate".

Conversely, castration is a component of conventional prostate cancer treatment.

Getting to the chemical-castration stage of metabolic syndrome might well be prostate cancer protective.

Omega 3 fats probably slow progression of metabolic syndrome, trans fats probably accelerate it.

If you want to get to the castration level of metabolic syndrome as fast as possible, to maximise this prostate benefit, never forget to ask for your favourite lipotoxin by name.

For metabolic castration you should always ask for Crisco.

Peter

Alternatively I have a couple of bricks available. It's an old anaesthetist's joke:

Surgeon: "I don't need to use anaesthesia for castration."

Anaesthetist: "Really, what's your technique?"

Surgeon: "I have these two bricks and I smash them together on the testicles."

Anaesthetist (aghast): "Doesn't that hurt?"

Surgeon: "Only if you get your thumbs in the way."

Diabetic nephropathy and the lost Swede

2011-04-25T21:11:00.014Z

Chris over at Conditioning Research forwarded me the link to the PLoS paper demonstrating partial reversal of diabetic nephropathy in a couple of mouse models. This isn't exactly a world shattering finding as anyone with diabetes who is not eating a mildly ketogenic diet probably has shares in dialysis machines or is being grossly mismanaged.

Anyway, the first thing to do with a paper like this is to check whether the authors cited Nielsen's 2006 case report of a human being having their diabetic renal failure halted and partially reversed. I mean, this might be relevant...

They didn't.

The Swedish group simply fixed a patient without a mouse model in sight. They got ignored for their temerity. Shocking to fix a human without the death of a single leptin deficient mouse, but there you go. And it's not so hard to do either............

As a complete aside:

It turned out to be interesting to go back and see where the mouse folks were coming from. They cited this paper.

Here is part of figure 6, the line to follow is the open triangles.

Up to day 84 a high fat diet was fed. As happens so often, the high fat diet is 31.7% sucrose/maltodextrin by weight and (gasp) 20.7% lard.

From day 84 onwards these lazy, greedy porkers of mice were switched to a diet which was 47.5% lard and, utter horror, 19.95% butter. Of course this is not really a high fat diet as it has no sucrose or maltodextrin...

Look at the weight drop to below (ns) that of the mice fed crapinabag throughout........

Obviously this must be the satiating effect of protein, so often cited by idiots as the reason for weight loss of LC diets. Except it's not, the ketogenic mice had the lowest protein intake, 9.5% by weight cf 24% in the crapinabag and HF diets. That is very low in protein.

Here are the actual diets in Table 1:

A far more plausible explanation is that ketosis induces dissatisfaction in these mice concerning their body image due to their obese state so they then started to cut calories and go to the gym every night. Duh.

Now please don't make me put up the fasting insulin levels. Aw, okay, you twisted my arm.

Edit: I noticed that these are the FED insulin levels, we don't get fasting levels in the paper...

No comment.

Peter

Yesterdayday was first meat day

2011-04-25T07:33:00.007Z

Edit: Today was fillet steak, OK so long as the piece is big enough to be sucked on without getting it all in her mouth at once...

Apparently babies are revolted by meat, just ask any vegan idiot

Peter

Palmitic acid: the horror never ends speculation

2011-04-17T19:51:00.006Z

Back in her PhD days my wife attended a seminar presented by a visiting researcher on some aspect of the inflammatory cascade. It was very technical and focused around the interaction of a certain ligand with its receptor at some critical juncture in whatever process they had devoted the last n years of their life to studying.

The ligand was all-cis-docosa-4,7,10,13,16,19-hexa-enoic acid. No one in the room had any idea what this stuff was, certainly not the extremely intelligent presenter, other than as a molecular key to a molecular lock. It's a stock lab reagent purchased in research grade purity from any one of a number of suppliers. You could equally order cervonic acid.

At the level of reductionism these people can work at there is no need to be aware that all-cis-docosa-4,7,10,13,16,19-hexa-enoic acid is available in gel caps from Holland and Barrett or is present in the nearest can of sardines as the more familiar DHA.

So imagine you are some newbie PhD student. You walk in to the lab and are handed a reading list a mile long. The lab has certain research lines you are going to slot in to, particularly focused around inflammasome activation by fatty acids. You got the post because you had picked up extensive experience with cell culture and inflammation research based around both endotoxin and asbestos, plus a track record of multiple Nature publications from your undergraduate work.

The lab you walk in to has cells in culture which go ballistic on exposure to utterly physiological concentrations of palmitic acid. At least six widely differing cell types behave in exactly the same way. This looks like a generic effect and puts palmitic acid up there with asbestos as a proinflammatory agent. You switch to Flora that very lunch time, and spread it thinly too.

The lab also has an animal house in the basement. The rats are either fed a standard lab chow or a red coloured greasy type of pellet oozing fat. The lab techs feed and water the ratties. Your job is to compare molecular aspects of white blood cell inflammasome activation as the high fat rats get fatter over the weeks. Once a fortnight someone brings you a blood sample to work with but, apart from that, you will never see the rats again...

What do you question? EVERYONE knows that eating fat makes you fat. Fat is fat. Do you give a monkey's about EXACTLY what is in the pellets which stain the tech's hands red when they do the feeding? It's a standard obesogenic high fat diet from www.testdiets.com. All obesity research uses it or something similar...

Would you sit down and work out whether the hydrogen atoms on either side of the central double bond of one type of fatty acid in one constituent of the 5TJN are aligned on the same side or on opposite sides of the bond? You know, cis vs trans configuration...

It's sloppy. It's possible. People will really be able stand up and say, as Ting does:

"The simple message is to avoid fatty foods as much as possible."

They probably have no doubts. They believe. It's complete bollocks of course. But I have this concept of how things work...

Peter

Palmitic acid: the horror never ends addendum

2011-04-14T19:12:00.006Z

Okay, Victoria sent me the full pdf.

This group used 0.2mmol/l or 0.5mmol/l palmitate conjugated to bovine serum albumin. All other fatty acids were completely excluded. No semblance of physiological mixtures were involved.

But guess what, they had a living mouse model too!

Now you have to be wondering exactly how they managed to get a mouse to have 0.5mmol/l of palmitate in its bloodstream, to the exclusion of all other fatty acids, during a glucose tolerance test. After all, their test tube model used pure palmitate, surely they used the same conditions in their mice? This is a Nature paper after all.

How did they perform this near miracle? Well the methods section (when you finally find it tacked on to the end of the paper, an afterthought down beyond the references) doesn't mention any attempt to measure live mouse fatty acids at all. They didn't. WTF, this got published in Nature!

The diet used was good old commercial 5TJN. When I downloaded the composition pdf from the Test Diet website to my laptop it said I'd already downloaded it some time before..... It's popular!

Here's the link, it won't embed:

www.testdiet.com/PDF/5TJN.pdf

How much sugar would you like with your Crisco? Remember, always ask for your favourite lipotoxin by name...

NO NO NO.

JUST SAY NO.

Say no to Crisco.

As so often happens, this paper details feats of molecular and cellular manipulation of breathtaking complexity. How can anyone be capable of doing this and yet be so stupid? Awesome!

Peter

And it gets worse. The stats were done on "Prism 5.0 for Macintosh". OMG they're Mac users. It shouldn't be allowed. Their laptops should be confiscated forthwith. Now. I'll have them please.

Palmitic acid: the horror never ends

2011-04-13T06:48:00.010Z

Chris forwarded me a link to this study. Read about inflammasones in tissue culture and quake. Here is the relevant line:

"These findings provide insights into the association of inflammation, diet and T2D."

It gets even better. Here is the best line from the press release:

"These results support the idea that inflammation plays a role in chronic disease," says Ting. "The simple message is to avoid fatty foods as much as possible."

OK, you take isolated cells, bathe them in 2mmol palmitic acid and they become unhappy. This is supposed to have something to do with eating a high fat diet?????

Just for fun I'm going, in my head, to eat some (gasp, horror) palmitic acid. Please don't do this at home, you probably don't want to inflame your inflammasomes.

I'm looking through my refrigerator for some palmitic acid but I notice that all there is in my fridge is Food. Bugger. What comes closest? Maybe butter??? Butter is undoubtedly Food, but it does have rather a lot of palmitic acid. Let's give it a try.

Half a pound of butter, here I come. Mmmmmmm. Nice. Yummie.

Now let's measure my blood palmitic acid levels . OOOOOh, post prandial triglycerides are up! Right on, I'm gonna die, some time soon. But what about the acid, the pamitic acid?

Ah, FFAs are also up up up. Success! 500, 600, 700, yes, 800micromol/l. If I really am in luck I might make that 2000micomol/l hit and drop right in to the inflammasome mediated diabetes zone. You know, that palmitic acid trip to nowhere.

Oh, but except for feeling a bit nauseous from all that butter in one go, I feel fine. Perhaps because I don't really have 2mmol/l palmitate in my blood stream after all. Double bugger. It seems like there is major, like MAJOR, contamination of my blood palmitate with oleate. Some is from the butter, some is from my own bloody liver cocking up the experiment. Using delta 9 desaturase to drop the occasional double bond in to long chain saturated fats ensures normal physiology.

Now, if I wasn't such a cheapskate I'd shell out the ackers to see if Ting et al used mixes of palmitate and oleate as well as either fatty acid in isolation. We know from the abstract that oleate does not inflame your inflammasomes... But I am a cheapskate, so I won't. Instead I'll go to this study:

"Low concentrations of oleate (0.1mM) completely inhibited palmitate-induced oxidative stress, SAPK activation, and apoptosis."

That's it, one tenth of one millimole of oleate completely negates the adverse effects of isolated palmitate.

Maybe check this one:

"Oleate alone did not cause mtROS generation and mtDNA damage, and its addition to palmitate prevented palmitate-induced mtDNA damage, increased total ATP levels and cell viability, and prevented palmitate-induced apoptosis and inhibition of insulin-stimulated Akt (Ser(473)) phosphorylation."

I could go on. No one, ever, at any time, has 2mmol/l of isolated palmitate in their bloodstream. A whiff of oleate is completely protective against the evil intentions of a researcher with a block of palmitate when viewed from the bottom of a test tube. It's called physiology. We are evolved to work this way. Knock out delta 9 desaturase and things become quite fun, but that's another story!

Citing the existing literature doesn't get you a Nature publication. Nor does it allow you to write press releases of utter stupidity to support low fat eating while simultaneously keeping yourself off the dole.

Peter

Fasting insulin and weight loss and calories-in vs calories-out

2011-04-02T06:00:00.009Z

I had this exchange in the comments on a previous post:

Frank said...

Hi Peter.  I'd say that I pretty much agree with your post. Insulin and caloric deficit are not mutually exclusive, ie, low-insulin could enhance fat loss on a caloric deficit or, looked from another perspective, a caloric deficit could enhance fat loss if someone has low insulin level.   I have only one question for you. For the sake of it lets make thing black and white.   What do you believe is the most important thing to do, in order to achieve weight/fat loss   a) be in a caloric deficit (your insulin level does not matter much)   b) having a low-insulin level (it does not matter much if you're in a caloric deficit or not).   Again, in real life, I don't believe they exclude each other, but if you could fix only one to have a weight loss, which one would you fix? Calories or insulin?   The way I see it is that, as you stated, insulin inhibits lipolysis, but more lipolysis does not equal more oxidation. It still has to be matched to energy expenditure. In that case, calories would be the most important factor. That's my point of view and it could be wrong.   I'm just wondering if you agree to some degree with it, because reading your post, I get the idea that you do.   Thanks for your time.

Peter said...

Ah Frank, now there is a question.  Without caloric deficit (and I want uncoupling proteins, sleeping metabolic rate, spontaneous movements, etc, etc, etc, everything, accounted for) there will be no weight loss.  But, in real life, if I could only alter just one, it would be insulin.  I would expect no weight loss but I would expect improved health.  What else matters?

There is a flaw in the answer I gave to this question. It's working at the Noddy level of calories-in vs calories-out.

The Noddy approach is perfectly adequate to explain the findings of GnK's paper (PR's weight loss excepted, if she genuinely ate all she was asked to), but embarrassingly stupid in the real world.

Let's look at calories-in vs calories-out in the fixed caloric phase of the Abredeen study.

Calories-in is total calories in to metabolism. There are two sources. Those from the diet, let's assume (incorrectly) these are genuinely all of the 2000kcal/d on offer. Then there is the supply of free fatty acids metered out from adipocytes under the regulation of insulin. Maybe a little glycogen, but I'll ignore that for the discussion.

Under LCHF conditions more FFAs are accessible due to lower insulin levels. More get used and, from Table 1, only 1930kcal of food are needed to supplement those calories-in from adipocytes in order to meet total metabolic needs. Hunger is low. Calories supplied are clearly able to meet voluntary calories out. Demand is within the limits of supply. Some food is refused.

Under MCMF conditions the higher insulin level allows less calories to be supplied from fat in to metabolism (adipose derived calories-in fall), so calories-in accepted from food spontaneously increase to the full 2000kcal/d. Under the study conditions we cannot tell if 2000kcal plus reduced adipose FFA supply is enough for as much metabolic activity as was possible under low insulin conditions. What if it is not? Now the real question is: Does lipolysis automatically increase to supply all needs for calories out? Why should it? Lipolysis is controlled by insulin. Insulin is high, lipolysis restrained.

If there is any shortfall in the calories from fat plus 2000kcal, there are only limited calories available to burn. You can't burn what you don't have. Calories-out would drop because they simply cannot exceed the supply available. I would expect the participants to automatically reduce their calories-out. There is no free lunch. Calories-out = calories-in. All need to be accounted for.

Is it be possible to force lipolysis in the face of hyperinsulinaemia to increase FFAs from fat to a higher level without lowering insulin?

Of course it is. There are other hormones in addition to insulin. You can throw around adrenaline, growth hormone, glucagon and probably a truckload of others I've not thought about. You can add in direct sympathetic nervous system innervation of adipocytes to effect lipolysis if you like. But these mechanisms come with a price. The price is hunger.

I think it's called working up an appetite.

In the Aberdeen study the attempt to maintain caloric intake failed during the LCHF phase because low insulin increased caloric supply from fat. Higher insulin in the MCMF phase limited calories-in derived from adipose tissue and may well have set a cap on total calories available for use during this higher insulin phase.

In Frank's thought experiment it might be easy to fix dietary calories-in, but people might refuse some of them if insulin was low enough for adipose tissue derived FFAs to be available.... If they ate all of their calories but wriggled in their chair a bit more because they had more calories available then the concept of calories-out being fixed is lost....

I'll just finish with a clarification of this phrase from another commenter:

"lipolysis is not beta oxidation"

This is, ultimately, accurate. That doesn't stop it being bollocks.

A rather more perceptive view is the situation comes from, of all places, the lipophobic cardiologists who published on FFAs and myocardial ischaemia:

"The rate of fatty-acid uptake and oxidation by the heart is controlled by their availability [33]"

Oh, interesting. Availability. A supply led system. Hmmmmmm. I would guess most FFA burning tissue would follow cardiac muscle. Now I can't quite remember what effect insulin has on lipolysis and FFA availability. Silly me.

Peter

Fasting insulin and weight loss

2011-03-24T21:13:00.011Z

I think that it might be a good idea to state here that I'm a calories-in calories-out sort of a person. Arguing about metabolic advantage is pointless. When a person loses weight they convert tissue to energy, amputations excepted. Where the calories go, whether it is BMR, thermogenesis, glycosuria, increased spontaneous movement, shivering etc, the calories always go somewhere. As far as I am aware no one is suggesting that calories evaporate. Certainly I'm not.

I am on blog as stating that dietary fat, in common with carbohydrate, is stored in the aftermath of a meal. If you did not store your dietary fat it would sit there in your chylomicrons until you were as hyperlipaemic as a diabetic on an ADA approved low fat diet. All fat which is not used for on going metabolism must be stored. It may take a few hours to clear chylomicrons but they do get cleared. Mostly in to adipocytes.

EDIT: There is an update on this post here.

Okay, let's look at the Grey and Kipnis (GnK) 1971 paper.

If you take a human like ET, who is maintaining a bodyweight of 142kg by eating 4,200kcal per day, you can adjust her macronutrient ratio to pretty well whatever you like and she will remain weight stable, provided you insist that she always consumes 4,200kcal/d. Insulin will plummet on a high fat diet and this will release necessary fatty acids from adipocytes. These FFAs, the Spawn of Satan, will be both released and used at an increased rate. But will she lose weight? Of course not. She will just re-pack her adipocytes with the extra fat from her fixed, 4,200kcal, low carbohydrate diet. Many people, myself included, can maintain weight stability on a low carbohydrate diet for years.

There's a nice paper about fat accumulation under low insulin conditions on my hard drive. It happens. I will post about it when I feel like it, it looks interesting.

There was one participant in the GnK study, RP, who refused to comply with the study protocol. That's a 20% non compliance rate. She under ate and lost weight. We get no information about her caloric intake at any stage. We know relatively little about her diet (ie sugar vs starch) before the study. We have no idea what sort of carbohydrate was used in the study diet. The only information we have about which phase of the diet gave the weight loss is this graph:

But we certainly have a failure of compliance in this study where an obese subject refused scheduled food and subsequently lost weight. That's worth remembering.

Now let's look at hypocaloric conditions in the same paper. DB, SM and DM were put on to 1,500kcal/d (Keysian starvation) from 2,200kcal/d, 3600kcal/d or 3,800kcal/d respectively. They, err, lost weight. They lost weight pretty nigh on linearly over 12 weeks whether their fasting insulin was 40microIU/ml or 15microIU/ml, produced by adjustment of their carbohydrate intake from 240g/d, down to zero and back to 240g/d.

NB I am perfectly willing to accept these results as they stand but just as an aside; none of the individual records shows any suggestion of a weight shift related to to glycogen depletion/repletion on these changes in carbohydrate intake. The LC phase included zero carbohydrate. The HC version of 1,500kcal provided 72% of calories as some sort of carbohydrate, ie 240g/d. Maybe even Weight Watchers depletes liver glycogen following an overnight fast... A bit odd but probably irrelevant.

Back to the results. The caloric intake was fixed and low. Fat was stored in the LC/HF group and accessed easily because insulin was low. Under high carbohydrate intake calories were stored mostly as glycogen and glucose was metered out to avoid hypoglycaemia. Any fat lost by the lower-but-not-zero rate of lipolysis under high insulin levels was simply not replaced.

Just eat 1,500kcal/d and you will lose weight. Eat more than 1,500kcal and you're a pig.

The study was designed to get exactly these results.

But, out of only five subjects, one obese person became a food refusenick. Various studies have had similar compliance problems, with obese participants refusing food. Let's look at some of them.

I knew there had been a paper by Krauss looking at lipoprotein subgroups during weight stability on assorted carbohydrate intakes. It didn't measure plasma insulin but, if we accept anything from GnK's work, I think we have to accept that under weight stability we can dial fasting insulin by adjusting carbohydrate intake. At least between 4% and about 72% of calories.

Krauss looked at diets composed of 54%, 39% or 26% of energy from carbohydrate, with a bonus group on 26% carbohydrate and (gasp) 15% of total calories as saturated fat.... These folks were instructed to maintain weight stability. This quote had the LC brigade, myself included, giggling if not rolling around in the aisles.

"Despite our effort to maintain constant weight, the 26%-carbohydrate, low-saturated-fat diet group lost more weight than did the 54%-carbohydrate group during the stable-weight period. There was also a trend for a greater reduction in percentage body fat with the lower-carbohydrate diets (P < 0.02, analysis of variance)."

The numbers are in Table 2.

My browser squishes the table, these are the numbers that matter, simplified. Remember, everyone was supposed to be weight stable:

Some of these numbers made p<0.05 or even <0.02, shrug. What is more interesting is the trend in accidental weight loss. Oh and look, the sat fat group didn't lose the most weight, just the most fat. I like that.

My take home message is that the lower the carbohydrate intake (and it is reasonable to assume the lower the fasting insulin) the harder it is to consume enough calories to maintain the obese state. It's possible, but not easy.

Then there is this study looking at the HPA stress axis under fixed calorie low carbohydrate or medium carbohydrate diet conditions. I'll just look at weight and insulin because the changes in the processing of cortisol are about as lucid as Krauss' early papers on lipoprotein changes due to dietary saturated fat. It seems reasonable to assume things improved on LC, otherwise any deterioration would have been headline news. This is a crossover study, the same people did a month on low carb and a month on medium carb, in random order. This makes the results tables somewhat unintelligible but it still comes close to replication the 1,500ckal section of GnK's paper.

Under weight stable conditions fasting insulin was 16.6microIU/ml on 57% carbohydrate. Under LC (4% carbs) conditions, on a fixed 2000kcal intake insulin dropped to 7.3microIU/ml. Weight loss was 7.2kg in 4 weeks. Eating 2000kcal of which 35% was carbs gave 4.7kg weight loss on a fasting insulin of 9.2microIU/ml. After correction for water shifts under LC there was exactly the fat loss accounted for by a caloric deficit of 66kcal/d. This was, oddly enough, exactly the caloric count of the food REFUSED from the 2000kcal provided during the LC phase........... Which they had been asked to eat. Obese people refusing part of a 2000kcal ration.

These folks where in a residential diet study. They consistently refused food they had agreed to eat during the "fixed" caloric intake phase, but only if the macronutrient ratio lowered insulin. As an aside the insulin level on LC was statistically significantly lower than on weight stability but the drop on medium carbohydrate was not. I would argue that the difference between either 7.3microIU/ml or 16.6microIU/ml and 9.2 microIU/ml is biologically significant even if p is > 0.05.

The original report details the menus and a battery of psychological test. There is a mass of information in this study from Aberdeen. As we all know, people mostly seem to get depressed and stoopid on LC diets. In this instance they just stopped being hungry!

Here is one of the best quotes, from the results section:

"The 3-d maintenance diet was designed to 1) neutralize the ketogenic state and replete liver carbohydrate stores and 2) to return hunger to baseline levels— equivalent to the maintenance period 1, before ad libitum feeding—recognizing that a carryover effect from the weight-loss phase existed. This design is particularly relevant for the subjects who were given the LC ketogenic diet first and then the MC nonketogenic diet."

"to return hunger to baseline levels......" I like that. Hunger on the ketogenic diet is not at baseline levels, it is lower. Just supplying MORE calories INCREASES hunger, so long as the calories have carbohydrate at 57%. Hungry and weight stable or less hungry while losing weight. I really like that.

Then a brief quote from this paper, also a weight loss rather than weight stability study, but the quote is too entertaining to leave out.

Fasting insulin was 11.6microIU/ml and 14.4microIU/ml at 3 and 6 months under ad libitum calories but progressively less stringent carbohydrate restriction. Under rigid calorie restricted low fat eating it was steady around 18microIU/ml.

"Based on dietary records, the reduction in daily caloric intake was similar in the two groups. For the greater weight loss in the very low carbohydrate group to be strictly a result of decreased caloric consumption, they would have had to consume approximately 300 fewer calories/d over the first 3 months relative to the low fat diet group (28). Although the inaccuracy of dietary records for obese individuals is well documented (31, 32), it seems unlikely that a systematic discrepancy of this magnitude occurred between groups of subjects who were comparably overweight."

We know that obese people always under report their caloric intake, just ask any obesity expert. Why on earth should this particular group of obese people consistently over report their caloric intake? That's not what fat people do.

You could rephrase this to speculate that the LC group either ate and "used" an extra 300kcal/d or became pathological liars who exaggerated their food intake by 300kcal/d, presumably to wind up the experimenters. Ketosis does make you stoopid and depressed, why shouldn't it make you in to a practical joker too?

Is anyone seeing a pattern of people (or rats) refusing food under reduced insulin conditions?

In the real world people eat when they are hungry, because they are hungry. They don't drink fixed caloric intakes of mysterious liquid formulations from researchers who's rat models are based on either sucrose or vegetable oil.

Can people actually gain weight on high fat diets? Of course they can. You can accumulate fat without elevated insulin. But you are much less likely to gain weight if you are not hungry.

I note that Chris Voight was not on a fixed calorie intake and was not hungry while he lost an impressive amount of his excess weight. I think his fasting insulin was low and he was performing lipolysis at an impressive rate.

Let's make this clear. Fasting insulin determines weight loss. The effect is primarily through reduced dietary caloric intake secondary to lipolysis-mediated access to adipose tissue calorie stores.

Overfeeding in excess of preferred calorie intake breaks the system. GnK simply disabled the mechanism of appetite control by fixing caloric intake. Fine to prove a point. It's this sort of research that has got us where we are today.

NB I think this decrease in hunger probably only occurs in obesity. For those of us who have adopted a LC eating pattern without the need for weight loss (and still have little excess fat) there are clearly other factors coming in to play, as there will be when a previously overweight person approaches target/ideal weight, what ever that might be.

Peter

Gourmand Rats?

2011-03-19T21:25:00.014Z

You know how it is when CarbSane quotes a paper which refutes the carbohydrate hypothesis of obesity. You really can't be *rsed to chase it but you also know that there will be a fundamentally flawed approach which needs looking at. CarbSane was my route in to Kathleen Axen's work with transfats, which I've probably not finished with yet, but which markedly ramped up my dislike of these industrial lipotoxins. I really enjoyed digging back through the Axen papers, though it took hours, and there's no way I would have hit on them without CarbSane's dire (and incorrect) opinion of LC eating based on the last of the triad. Cracking.

So it is with Grey and Kipnis' paper on the irrelevance of fasting insulin to weight loss. It leads back to a rat paper (aren't you surprised!). The rat model was developed to allow rats to gain weight under hypoinsulinaemic conditions. So GnK had a high carbohydrate diet and a low carbohydrate diet for their rats, both of which promoted weight gain, but the LC diet did it without raised insulin. Here are the diets:

Nice.

But here's the funny part. They did a whole load of experiments (very interesting, seminal work on pancreatic glucokinase induction/suppression) which required equal calorie intake between a group on the high carbohydrate diet and another group on the zero carbohydrate diet. Let me quote:

"Since the low carbohydrate-high fat diet is less palatable to rats than the high carbohydrate diet, pair feeding was accomplished by determining the caloric intake of the low carbohydrate fed rats and then offering a comparable [ie less than they would have eaten] caloric amount of the high carbohydrate diet the following day to another group of animals."

You just have to admire the palate of those hypoinsulinaemic rats. Of course it's just possible they weren't ratty gourmands, it might actually be that they just weren't hungry because their fasting insulin was low and no one was ordering them to eat more than they felt like................

The giggles that come from following CarbSane's leads! Gotta get them from somewhere.

More on the cited Grey and Kipins 1971 paper when I've finished with the modern studies looking at the same question. There are some nice ones.

Peter

Cholesterol and cholestyramine

2011-03-15T20:32:00.015Z

I'm not ready to post about this study yet but I thought I'd just put up a flag for its existence. It has long puzzled me why cholestryamine should show any benefit in cardiovascular disease, even if any benefit is offset by increased non cardiovascular mortality.

It turns out that cholestyramine increases the blood level of at least one oxysterol 25 fold. I would guess that this is accumulated in Lp(a).

This is of particular interest to me. I'll get around to why one day but thanks to Leib at THINCS for the lead in to the whole area.

So cholestyramine: When you look at all of the metabolic benefits which come with this wonder drug it's just amazing it doesn't save any lives.

Could it be that the multiple metabolic benefits (or the accumulated oxysterols, gasp, heresy again) reduce cvd mortality while the low cholesterol encourages you to throw a punch in some bar in down town Dallas?

Peter

Spawn of Satan in the gym

2011-03-15T13:10:00.013Z

I think it's pretty well established that free fatty acids are the Spawn of Satan.

This paper came my way through Luca and THINCS. Free fatty acids are just appalling. Read this paragraph from the discussion section and clutch at your chest:

"... studies have shown that a fat-enriched meal, in contrast to a high carbohydrate meal (HCM), is associated with endothelial activation [30] and may initiate injury to the blood vessel wall [31]. Increased circulating FFA and their derivatives have also been shown to be particularly deleterious on myocardial function during ischemia and reperfusion (for review see Ref. [32]). Indeed, in the ischemic myocardium, long-chain fatty acids accumulate quickly. The rate of fatty-acid uptake and oxidation by the heart is controlled by their availability [33]. Exogenous fatty acids, the main metabolic fuel of the myocardium under aerobic conditions, are detrimental during oxygen deprivation since their presence further augments the accumulation of long-chain acyl esters in the myocytes. The accumulation of lipids and their degradation products may contribute to the progression of injury. Furthermore, during reperfusion, fatty-acid oxidation can quickly recover and become the dominant source of ATP production. A high rate of fatty-acid oxidation contributes to a marked decrease in cardiac efficiency during the ischemia–reperfusion period [34]. We have previously shown that pharmacologically-induced increase in plasma FFA can significantly reduce the ischemic threshold in patients with stable coronary artery disease [35]. Recent studies have shown that FFA may also attenuate endothelium-dependent arterial vasodilatation [17,36] and increase sympathetic drive and alpha 1-adrenergic receptor reactivity and tone [37]. In addition, a HFM leads to an increase in calf vascular resistance [38]. All these data support a role for FFA and triglycerides both in vascular and muscular metabolic regulations."

I have to say that I've been through most of the references cited and many of them are quite hysterical. But that's another matter, maybe another post.

So the people who wrote the above paragraph had the bravery to feed a high fat meal, a high carbohydrate meal or nothing (on different days) to some cardiac patients and then treadmilled them to ST segment depression, ie until myocardial ischaemia set in. Obviously a high fat meal, particularly one based on saturated fat (as the test meal is claimed to have been, you don't get enough detail to tell what they used) should have crippled these people.

It didn't. The high fat meal had absolutely no effect on time to ischaemia.

How do they explain this? Easy, the high fat meal may have been a high fat meal, but it never raised plasma free fatty acids! This is what they say:

"However, this study was targeted to assess the role of a high fat meal and not of high serum FFA concentration; in fact due to the antilypolitic effect of the hyperinsulinemic response to the meal the serum FFA concentration was lower than in the fasting state."

Cunning hey? Just spike the high fat meal with exactly the correct amount of carbohydrate to lower lipolysis derived FFAs by an amount slightly more than the test meal generates and there is no overall change in FFAs (p > 0.05, ns) so no change in time to ischaemia! Beautifully done. But bollocks never the less.

Aside: Weird how you can use insulin to inhibit lipolysis in heart patients, just like treating ketoacidosis. You might almost imagine that insulin has something to do with weight control, I dunno... Back to the bollocks:

The same number of calories consumed as mostly carbohydrate dropped the time to ischaemia from 376 seconds to 297 seconds, p = 0.003, Table 2, line 13. This is despite the fact that carbohydrate meal reduced the Spawn of Satan from 0.89mmol/l to 0.27mmol/l, p = 0.002.

Of course with all that hard evidence about FFAs delaying myocardial recovery you really would expect an accelerated recovery from ST segment depression after the high carbohydrate meal, after all FFAs concentration is only a third of that under fasting conditions. In fact we can see from line 15 that the high carbohydrate meal gave a recovery time 30 seconds slower than after fasting, with all of that Spawn of Satan released from adipocytes due to not eating for a few hours. The high fat meal gave a recovery time which was 30 second faster. The spread in the numbers means that all of these differences are ns. No way can we tell how close p got to that good old 0.05, ns is all we get. But you really do have to wonder about how this fits in with all of those references in the above quote!

These authors do not go so far as to make dietary recommendations for folks with cardiovascular disease eager to spend a few minutes on a treadmill after supper.

Cardiologists back in the 1990s were not so reticent. This paper came out in 1996. It is essentially a poor man's version of the modern epic discussed above, with identical findings. What is the dietary advice if you have angina in Sheffield in 1996? Eat fat or carbohydrate before your jogging?

"It would be difficult to advise patients to take a higher proportion of calories as fat in the diet to minimize these early adverse cardiovascular effects, because of the potential effects of dietary fat on atherosclerosis genesis."

And the solution, just say no!

"...patients with angina should be advised to limit their activities in the early (first 30 min) postprandial period because of the reduction in angina threshold."

So if you are planning some post prandial exercise you can have an extra 79 seconds before myocardial ischaemic sets in by having cream instead of potatoes, but don't. Instead just put your feet up!

Peter

Potatoes and weight loss (1)

2011-03-06T20:49:00.044Z

I tried and failed to produce a comprehensive post about weight loss on an all potato diet. It runs to too many pages. This is a brief simplification.

Eating 2-3000kcal/day of potatoes spikes blood glucose. The more potatoes you eat the more you spike glucose. The pancreas responds to hyperglycaemia by secreting insulin but also by upregulating pancreatic glucokinase production, which increases insulin secretion per unit rise in glucose. After a couple of days on an all potato diet your pancreas will be producing impressive amounts of post prandial insulin.

Adipocytes respond to the insulin by shutting down lipolysis. Plasma free fatty acids drop and fat loss stops.

Insulin is degraded by insulin degrading enzyme. Very, very, very crudely (with a ton of qualifications, read the paper!) insulin action leads to insulin degradation. All insulin sensitive tissues degrade insulin. The liver is a massive sink for insulin, especially on a high carbohydrate diet. Anything which increases hepatic insulin sensitivity should increase hepatic insulin degradation. A sudden ceasation of free fatty acid supply from adipocytes will increase both hepatic insulin sensitivity and hepatic insulin degradation. A potato diet supplies relatively little in the way of fatty acids so there is also little dietary fat to supply the lipid intermediates to encourage hepatic insulin resistance.

Much of the hepatic uptake of glucose occurs without the direct intervention of insulin. The liver has large numbers of GLUT2s on its cells, which allow insulin-independent hepatic glucose uptake via a simple concentration gradient. The gradient is maintained by the intracellular phosphorylation of glucose, which allows its prompt removal to metabolism or storage as glycogen. Hepatic glucokinase does this phosphorylation and the production of the glucokinase enzyme in the liver is, of course, controlled by insulin. Increased insulin leads to increased glucokinase production and enhanced GLUT2 mediated glucose uptake.

Without fat, bulk calories are stored as glycogen, excepting that there is a little de novo fat synthesis from glucose in the liver. Hepatic glycogen does not cause hepatic insulin resistance. In the near absence of FFA supply the liver maintains insulin sensitivity and the ability to degrade insulin. Nothing like as much insulin reaches the periphery as is produced by the pancreas in response to 2-3000kcal of potatoes.

The second effect of shutting down free fatty acid supply from adipocytes and diet is the loss of fatty acid intermediates in muscle. Insulin sensitivity increases, the amount of insulin needed to facilitate glucose uptake by muscles decreases. Insulin secretion from the pancreas will then decrease but hepatic extraction of insulin continues while ever carbohydrate adaption continues.

The ultimate determinant of weight loss is fasting insulin. This determines how much lipolysis occurs during the period before the next meal. No one expects to lose weight during the 4 hours immediately after any meal. The following 8 hours, especially overnight, is when weight loss occurs.

Post absorptively, without dietary glucose input, there is no stimulus for anything other than basal insulin secretion. Fasting insulin will be low because muscles are insulin sensitive so relatively little insulin is needed for glucose uptake. As fasting insulin levels drop lipolysis will restart. Free fatty acids will feed back to the liver to cause some degree of hepatic insulin resistance, decrease first pass metabolism and stop too profound an hypoinsulinaemia occurring. But fat loss will happen.

So you have to ask whether an almost all potato diet genuinely leads low fasting insulin and subsequent weight loss. For my perspective the answer is yes. The precedent for this has to the Kitavans with fasting insulin levels of 4.0microIU/ml.

The next question is whether anyone could do this. That, I suspect, depends on how broken your liver is, ie is there irreversible hepatic insulin resistance. If you are overweight secondary to simple fatty liver, which is completely reversible, I suspect the answer is yes. If you have pathology in your liver such as NASH, especially with fibrosis, I think you might not respond in the same way. The more of a problem you have with obesity the less likely you are to lose weight or experience appetite normalisation (translates as access to adipose tissue calories). Ultimately the ability to live on varied macronutrient ratios comes down to how broken you are, especially your liver. Why a broken liver requires low carbohydrate eating is another post.

Is it healthy for someone with a functional liver to live on potatoes? It is clearly possible in the medium term. Cooked tubers have a respectable history of human usage. If you are not broken it might be a reasonable diet. There are no trans fats in spuds. There are minimal omega 6 fats. There is no gluten. There is just enough fructose to activate hepatic glucokinase without generating de novo lipogenesis. There is adequate high quality protein. On the down side there are a stack of vitamin and mineral deficiencies waiting in the wings.

I have no doubt that Chris Voight lost weight on an all potato diet. I also have no doubt that he was neither chronically hyperglycaemic nor hyperinsulinaemic.

There is no way of putting numbers to the framework with the data I have at the moment, but the physiology is comprehensible.

OK, up for shredding.

Peter

There are a whole stack of follow on posts to this one but let's see how this one holds up first...

Ratty at a year

2011-03-01T19:49:00.005Z

Ratty, about a year old, 410gm. Ad lib high fat diet, mostly portions of our food. Lots of lard, probably not diabetic! He is very, very strong for his size and can open the cage door after I bent the door clip tighter. Now he sleeps in rat Alcatraz overnight.

Peter

Oh, and here he is with Ping in the background...

Peter eats vegetables

2011-02-28T21:47:00.003Z

Vegicide at home. And there's a mushroom under the round of goat's cheese... I do this sort of thing occasionally.

Peter

The 14.4% solution

2011-02-21T21:26:00.019Z

Ok, Ratty, myself and family really are doomed. Again.

How many times does this have to happen before I really start peeing glucose down the loo?

Here's the abstract:

OK, finished that? Clever stuff. Are you scared of a ketogenic diet? Want to pay for the full text to see how I'm going to get diabetes? Don't bother, Emily that nice psychiatrist at Evolutionary Psychiatry has already sent me the pdf. This is what it will take you 30 seconds to locate:

And this is the discussion on the relevant lipotoxin, with my translations in italics:

The present study used hydrogenated corn oil for dietary fat sources since it has less harmful effect on diabetes than lard, even though it contained trans fat.27

Translation: This study did not use hydrogenated corn oil. It used PARTIALLY hydrogenated corn oil, full hydrogenation would eliminate all trans fats. Bollocks statement number two is that trans fats have a less harmful effect on diabetes than lard. Ref 27 is an opinion piece/review by Walter Willett and friends. They suggest "Consumption of partially hydrogenated fats should be minimized". Correct. Willett's weird ideas on saturated fats are as well known as they are incorrect. There is no suggestion in the abstract of the cited review that trans fats are less diabetogenic than lard. Anyone can slog through the free full text to see if there is any justification for the beneficial effects of trans fats vs lard. I can't be @rsed.

The role of trans fat in the development of type 2 diabetes has not been as widely investigated.

Translation: Kathleen Axen beat us to this in 2003 but we're not going to mention someone who is that far ahead of us.

EDIT: Perhaps these jokers only read the abstract of the study in which Kathleen Axen was so limited on word count that any mention of trans fats was omitted from the said abstract. Perhaps Park et al only read the abstract and missed the fact that they had been pre empted by eight years on the glucose dysregulation effects of trans fats. Sigh, the penalty of tight word counts.... Back to translating the discussion. END EDIT

The Nurses’ Health Study,28 the largest and most detailed epidemiological study, showed a positive association between trans fat intake and risk of diabetes, with a clear dose–response relation.

Translation: The NHS is observational and suggests the hypothesis that diabetes is caused by trans fats in a dose related manner. Probably true but needs testing.

However, small epidemiological studies or those that did not include repeated measures of diet did not indicate a positive association.29

Translation: Small, third rate studies are small, third rate studies. We'll cite them because we want to to use trans fats to produce pathology and blame it on the ketogenic nature of our experimental diet.

Tardy et al.30 showed that it [trans fat] does not seem to impair insulin sensitivity, at least in the muscle of rats.

Translation: The site of trans fat toxicity is not muscle. And so???? What about the liver, central to diabetes?

KTD [as used in the current study] did not reverse, but rather exacerbated, the effects of pancreatectomy-induced diabetes. Thus, hydrogenated corn oil was used as a dietary fat instead of lard.

Translation: We're idiots

And from the summary, the last sentence of the paper:

Therefore, KTD, but not ketone, exacerbates impaired energy and glucose metabolism in type 2 diabetic rats, suggesting that it may not be an appropriate dietary intervention for non-obese type 2 diabetic patients.

Translation: A ketogenic diet based on 14.4% of dietary fat in the form of trans fats will make you ill. Very ill. WE'RE IDIOTS.

TRANS FATS: JUST SAY NO.

JUST SAY NO

NO.

Peter

Dr Wolfgang Lutz Obituary

2011-02-13T15:51:00.003Z

I've been off the net for so long I've no idea whether this is common knowledge. Dr Lutz was a core influence on me. His writing is so down to earth, pragmatic, sensible and thought provoking. I don't know what else to say.

Peter

Normoglycaemia independent of insulin?

2011-02-12T20:22:00.042Z

This post has been lying around for a while so I'll just stick it up before getting on to IDE and potatoes.

You sometimes have interesting conversations in reception. A lady commented to me that she had no trouble getting arthritis meds in to her dog, some difficulty with antibiotics and that there was no way that she could persuade him to take the tramadol which had been prescribed as a supplementary analgesic for his arthritis.

I mentioned that he might not find the psychotropic effects of tramadol pleasant. A bit like morphine, not everyone finds the effects enjoyable. She concurred about the effects of morphine. It turned out that she had once been given morphine after surgery and had lost her automatic ability to breathe.... A sort of iatrogenic and thankfully temporary Ondine's curse. More poetically here.

In her case the solution had been that a nurse was assigned to sit by her bed and remind her to take a breath whenever she forgot, until automaticity of breathing returned as the morphine wore off. It's a rare side effect.

It started me thinking about control systems. The pancreas monitors blood glucose and responds with insulin and glucagon. It has a generous nerve supply with a whole host of neurotransmitters affecting insulin output. There are also glucoreceptors in the aortic bodies feeding information to the autonomic nervous system. There are, not surprisingly, nuclei in the brain which have glucosensors. There are probably insulin receptors in the brain too.

I think it is just worth pointing out that I have absolutely no problem with the fact that the brain controls blood glucose. Not the pancreas, not the liver, not the adipocytes. Long term stability needs brain input. You could probably say the same about body weight.

It's an integrated system.

But I doubt very much that the brain is central to the bulk management of metabolism. You would hardly expect a regulatory system such as the pancreas/liver/glucose axis to be intrinsically unstable and only kept functional by continuous and aggressive brain intervention. Metabolism ought to be largely self regulatory, with fine tuning by the brain to meet specific conditions.

Aside: Apparently the Eurofighter is intrinsically unstable in flight and is kept stable by enormous computing power and continuous hardware activity. It uses this intrinsic instability, given tightly controlled expression, in order to flip the aircraft from zero to 7 G in a completely unreasonable period of time. Keeping the pilot conscious under these conditions is the challenge to be met. I only heard any of this because we had an interesting presentation about this latter aspect at an anaesthesia meeting on cerebral perfusion pressures not so long back... Back to metabolism:

There is clearly a regulatory set point for the control of breathing. There is also one for blood pressure, blood sodium, potassium, pretty well everything else. I manipulate many of these daily to earn a living. Why not one for bodyweight?

At the moment I have an insulinocentric view of metabolism and bodyweight. Insulin appears to explain a fairly large chunk of weight control issues. It doesn't intrinsically need a set point concept, but there is every reason to accept some brain input to determine bodyweight. But the idea that the brain can over ride the obesogenic effect of a diet which requires chronic hyperinsulinaemia to maintain a semblance of health is very hard to accept.

It was working through these concepts that I dug out a fascinating paper on leptin and blood glucose emailed to me by Stephan a little while ago. I finally got to read it in depth last week.

The streptozotocotin diabetic rat strikes me as a pretty good model for type 1 diabetes. It looks to be a pure beta cell failure model, ie it lacks the stupidity of considering metabolic freaks such as the Otsuka diabetic rat as in any way representative of any form of human type 2 diabetes. I have time for STZ diabetic rats as being a model for type 1 diabetes. STZ produces acute, persistent and profound hypoinsulinaemia.

The researchers made some rats severely diabetic with STZ (BG > 400mg/dl), then infused leptin in to the cerebrospinal fluid within the third ventricle of the brain.

End result: Normoglycaemia. No change in blood insulin level.

That's quite impressive. No, it's bloody amazing. They did a ton of other things too and had a number of excellent control groups. The conclusion the researchers reached is that there appears to be neural control of hepatic glucose synthesis and output, plus neural control of muscle glucose uptake. They're probably correct. It's a very interesting paper. But is a massive intracranial infusion of leptin genuine physiology or is it pushing a fine tuning system to its ultimate limits using a chemical gorilla? Turbocharging a Morris Minor to out-accelerate a performance BMW?

They were putting almost as much leptin per minute in to the CSF/brain volume as would be produced by whole body fat mass. They probably achieved intracerebral concentrations of leptin way above what might every be produced in plasma.

Of course the goal of the group is to produce a centrally acting leptin mimetic to treat diabetes. Hmmmm, the unintended consequences will be interesting!

As always, picking through the results tables provides a wealth of information to be fitted in to the insulinocentric view of metabolism.

Let's look at the blood insulin levels:

It looks like STZ produces profound hypoinsulinaemia. It doesn't matter what else you do, insulin is low after STZ. No problems here. Hypoinsulinaemia across the board.

Before we look at blood glucose levels let's peek at leptin levels:

Interesting? Well the rats in the control non-diabetic group have lots of leptin. Unless the rat is being given a subcutaneous infusion of leptin (right hand column) there is very little leptin in the blood stream of the diabetic rats. Why so? STZ does nothing to leptin production. But hypoinsulinaemia does a great deal to lipolysis. These rats have had uncontrolled type one diabetes for a couple of weeks before the six day experiment. We don't get any bodyweights in the paper but leptin reflects adipose tissue mass. The STZ rats are profoundly fat depleted compared to the non diabetic controls. I think they're emaciated. This thin:

"WAT [White Adipose Tissue] had clearly atrophied in size in STZ-SAL rats. WAT in STZ-LEP and STZ-PF rats was further atrophied compared with the STZ-SAL group. For that reason, we could not extract enough RNA for Northern blotting"

That's thin.

So now let's look at weight change. During the 6 day experiment the non diabetic control rats gained about 15g. The hypoinsulinaemic groups all lost 15-25g bodyweight (except the semi starved group in column 4, starvation of type one diabetics is not advised, ND for leptin in the above graph wasn't that they didn't look for leptin, it's just the amounts present where below the limits of their assay).

This is irrespective of whether they were spilling glucose through their kidneys or not. Hypoinsulinaemia allows lipolysis. Drop insulin and you drop fat, however much rat carbohydrate-crap-in-a-bag you eat. Intracerebral leptin does not stop this.

Now let's look at food intake:

STZ diabetic rats become hyperphagic. At least when they are fed on rodent chow and allowed free access. High carbohydrate, low fat. As the authors point out this does not happen if you feed a high fat diet but I've blogged about this elsewhere.

I'd just like to consider why this hyperphagia should occur from the hang-glider perspective, rather than the Eurofighter perspective.

STZ rats lack insulin. They do lipolysis to extreme levels and run their muscles on fatty acids. Until there is not a lot of fat left, as reflected by hypoleptinaemia. Down on the ground the cells needs calories but there is not enough fat left for this level of hypoinsulinaemia to provide free fatty acids for metabolism. But it is possible to get blood glucose levels high enough to use non GLUT4 transporters to get glucose into muscle cells (see here). With hyperglycaemia there is a chance of survival. To do this you need marked hyperglycaemia. You need it, so metabolism does its best to provide it. In fact these rats will have been hyperglucagonaemic to help raise their blood glucose.

So the rats will eat a ton of glucose precursor, fail to retain it in the liver due to hypoinsulinaemia, add as much to it, using glucagon, as possible and push glucose in to muscles using the brute force of a concentration gradient. The cost is calorie loss through glycosuria and whole body hyperglycaemic damage. But death is postponed. Life is tenaceous.

The STZ control rats ate over twice as much crapinabag as the non STZ controls while continuing to lose weight hand over fist.... Good old hypoinsulinaemia and the body's adaptation to it.

The paper certainly gives support to the concept that the brain is significantly involved in glucose homeostasis. How this will relate a fat mass set point is a line of thought I'm looking forward to seeing Stephan develop.

I rather like this paper. It doesn't need me to move from my insulinocentric bias for weight loss. Ah, good.

Back to LC for diabetes and adaptation to high carb next.

Peter

Earning a crust

2011-02-12T13:44:00.013Z

We seem to have had a fair number of diabetic dogs come through work recently. Most of them have presented in ketoacidosis. This is a direct consequence of catastrophic insulin deficiency. Hypoinsulinaemia leads to unrestrained lipolysis with production of ketone bodies to the point of profound metabolic acidosis, vomiting, dehydration and risk of rapid death. Oh, and weight loss.

I keep reading snippets about the unimportance of insulin in the control of weight loss from various sources in the blogosphere, so it's sort of tempting to inhibit lipolysis with a couple of big, high calorie blocks of butter or maybe by an Intralipid infusion (yeugh, soyabean oil intravenously, disgusting). But, what the hell, I'm still a bit of a traditionalist on occasion, so I still shut down lipolysis with insulin.

It doesn't seem to matter how much insulin you inject. Once upon a time I would have reached for soluble neutral insulin and bunged it in by intramuscular injection. I had been considering changing to using a GIK (glucose/insulin/potassium) infusion for ketoacidosis but the loss of any soluble insulin preparation from the veterinary market in the UK has stopped my thoughts along those lines.

So now it's lente insulin (the only formulation we have left) by subcutaneous injection and aggressive fluid therapy to allow its absorption. Ultimately it doesn't matter. Any old insulin at almost any old dose rate will inhibit lipolysis well enough to get ketone production under control. You then start seriously supplementing with potassium while catching the hypoglycaemia with an iv glucose infusion as soon as the insulin level in the blood gets high enough to start doing things other than inhibit lipolysis..........

Replacing the missing insulin inhibits lipolysis first. As the blood insulin level increases it then shifts potassium from plasma in to cells. Still higher levels get GLUT4s on to cell surface membranes and facilitate glucose transport.

This is utterly basic A&E work.

Of course the lipolysis of weight loss might just be different from the lipolysis of ketoacidosis. I dunno. Stranger things have happened.

The other thing which has happened is that I have accumulated a couple of these patients who have turned out to be unstable diabetics. They are fascinating cases. You have to understand that as a heretic I try keep my nose out of other clinician's cases, especially diabetic dogs. The basic standard veterinary approach to diabetes is to feed your patient a meal of utter crap, mostly made of sustained release carbohydrate, and cover it with an industrial dose of 12 hour acting lente insulin. Repeat every 12 hours. You can book the cataract surgery for a year's time on the day you make the diagnosis.

The first patient, I'll call her Grace, is a spaniel with a two year history of dry eye, failure to produce tears. A sort of type one diabetes of the eye... What does dry eye have to do with diabetes? Dr Penny Watson of Cambridge Vet School gave a very perceptive presentation about chronic pancreatitis leading to diabetes at the 2010 BSAVA congress. In dogs pancreatitis is often a chronic inflammatory disease which can end up as a "type one like" diabetes syndrome or, alternatively, as an exocrine secretion deficiency giving a failure to digest food. Occasionally both. Which happens to occur in a given individual is probably a genetic lottery.

This dog had had dry eye well before her pancreatic beta cell failure. Dr Watson pointed out that dry eye is an autoimmune attack on the tear producing glands and the attack is aimed at ductal tissue. Stem cells for pancreatic beta cells are derived from pancreatic ductal tissue, which is similar enough to tear gland ductal tissue to produce an association, both diseases in the same patient. Cocker spaniels are far more commonly affected than other breeds. She had some absolutely amazing immunohistochemistry slides.

A sort of Sjögren’s Syndrome of the pancreas, probably another gift of gluten.

The other patient is a middle aged terrier, let's call him William. He has a two year history of chronic hepatopathy before presenting as a type-one-like diabetic. I'd guess he has a combination of non alcoholic fatty liver disease combined with non alcoholic fatty pancreatic disease. He was on a diet of commercial ultra crap, rice mixed with a mess of enzymically degraded protein to limit pre existing skin allergies. Imagine trying to catch the glucose spike from a bowl of white rice with a slow onset sustained release insulin. That initial spike of blood glucose was being caught, too late, with an enormous dose of lente insulin. Two hours later he would have a blood glucose of around 10mmol/l, but dropping like a stone. Suddenly the next reading would be back above 30mmol/l. Dr Bernstein doesn't have a lot of time for the Somogyi overswing. I do, certainly for this dog. The liver is loaded with glycogen, it panics and dumps a fair dose of glucose to (over) correct the incipient hypoglycaemia.

With the standard management approach both dogs had immediately come out of ketoacidosis and had gained weight over several weeks. Did I mention that insulin inhibits lipolysis? Ok, I'll drop it in to casual conversation again. Insulin inhibits lipolysis. Weight gain? Now there's a surprise. Of course there is no ketosis but also no suggestion of normoglycaemia at any stage of a 12 hour glucose curve either.

For some reason Grace had been dropped in to the middle of an afternoon consulting session for a random, post absorptive blood glucose check with me, presumably to adjust her insulin dosage. I wasn't her clinician. I think this reading was somewhere around 25mmol/l. She was ravenous, depressed and polydipsic. Next morning I had her admitted, halved her insulin and fed her a can of cat food with a carbohydrate content of approximately zero, except whatever cooked liver was in the can. The curve came down from somewhere over 35mmol/l to about 14mmol/l and stayed there. We've incremented her insulin up and are aiming for peak blood glucose below 10mmol/l and post absorptive levels below 7mmol/l. Probably the best we can do with lente insulin.

William came to me because lente plus ultracrap was giving completely random blood glucose levels. His owner had been offered referral to an endocrinologist or to see the weird in-house vet who didn't feed sugar to diabetics. That's me. They chose to see me for some reason.

He behaved similarly to Grace when fed all meat cat food and half dose insulin, which is good but we probably need better glycaemic control if we are going to get his hepatopathy to halt. We're getting post absorptive glucose levels between 5mmol/l and 7mmol/l but there is a post feeding spike to over 14mmol/l, which suggests there is a lot of liver in the cat food to provide significant glycogen in the diet. But so far he's a lot more stable now than he ever was on ultracrap.

So why low carbohydrate? Why not simply adjust insulin to cover normal diabetic crap-in-a-bag?

This comes down to the difference between exogenous insulin and pancreas secreted insulin.

Let's recap the two main functions of insulin. First is the inhibition of lipolysis, I may have mentioned this before. This bit is easy.

The next is the suppression of glucose release from the liver. This is utterly core to normoglycaemia. This is not quite so easy.

This is because insulin is normally produced by the pancreas and it travels directly to the liver. There is first pass metabolism by the liver, lots of it. The liver extracts between 50% and 80% of all of the insulin produced by the pancreas. Relatively little ever gets to the systemic circulation. This residue is what should be controlling adipocyte function.

If we turn this on its head we can say that we need to provide relatively high levels of insulin by subcutaneous injection to achieve those levels at the liver which would normally be delivered from the pancreas. But we end up not just bathing the liver with this specific high concentration of insulin. To reach "pancreatic" concentrations at the liver, from a subcutaneous injection site, we will have to hit the adipocytes far harder than we want to. We might well achieve adequate control of hepatic glucose output but at the cost of suppressed lipolysis. Weight gain. And hunger of course.

You could add in a third role for insulin as the management of dietary carbohydrate, ie portal vein glucose sequestration in to the liver and its metabolism by muscles when it spills over in to the systemic circulation. Generally I regard this as what Douglas Adams described in the Hitchiker's Guide to the Galaxy as an SEP. This is a "Somebody Else's Problem".

You want to do that? Fine, you sort out the mess.

I really have to discuss this in some detail because it is perfectly clear that non diabetic humans, so long as they have a functional physiology, can generally deal with massive amounts of carbohydrate rather well. So well that they can lose weight, rather a lot of it, by eating a diet of potatoes alone. This perfectly compatible with why LC is the logical and necessary approach to diabetes. That needs a separate post with a few links to pubmed rather than me rambling on about how I earn my living.

Peter

2011-02-12T09:22:00.002Z

I have net access again, broadband rather than a mobile phone dongle with intermittent connection that would only talk to my wife's PC because my mac has not needed any sort of system update since a very long time ago!

Posts are coming and I'll try to do something with the pile of comments which need moderating with some attention and a whole stack of emails too.

Woo hoo, click and page loads, no 10 minute wait, that's good!

Anacetrapib and phytotoxins

2010-12-28T23:08:00.023Z

Just starting to find a little time to post. This seems like a worthwhile snippet as a follow on to the anacetrapib post, easier to put up than the cooking epics on insulin and the liver, parts two onwards........

Ok, the usual recap:

First there was cholesterol. It was bad, life was simple.

Then came Good cholesterol, HDL battling the Bad cholesterol, LDL.

Then there was Good LDL, large buoyant battling with Really Bad LDL, small dense LDL, sdLDL.

Not only that but native LDL appears to be harmless, it's only oxidised LDL which is the killer, oxLDL.

So the evil sdLDL is only really evil because it is more easily oxidised than fluffier LDL. Maybe, but in general I tend to have glazed over by now, befuddled by the blur of the moving goal posts.

But just occasionally something does grab my attention, especially if it markedly deepens the hole being dug for itself by the lipid hypothesis, like anacetrapib.

It was thanks to Dr Davis that I grasped the concept of CETP inhibitors as eliminators of sdLDL. That's what they are. If you believe in the lipid hypothesis it must be pretty interesting to have a drug which virtually eliminates sdLDL while increasing the body count for cardiovascular deaths, even if 4 dead out of 808 vs 1 dead out of 804 does not reach statistical significance.

But the real gem from Dr D was the finding that anthocyanins are CETP inhibitors. You no longer need to sign up for the next anacetrapib trial to die of a heart attack in the cause of the lipid hypothesis. You can buy a do-it-yourself CETP inhibitor in the form of a purple plant dye.

EDIT pre posting: It always amazes me that someone as perceptive on blood glucose, and indirectly on blood insulin, as Dr Davis can still believe the lipid hypothesis. Really believe. Fascinating.

There now, we all know plants are all natural, healthy and safe. Perhaps that includes recreational plants like Deadly Nightshade, Nux Vomica and Henbane. As an alternative to anacetrapib you can only hope the anthocyanins don't work!

If they do work at least you might have the consolation that you died with cracking lipids.

Peter

PS, taken from here on flavonoids, discussed here:

"However, a similar decrease in protein oxidation [on flavonoid elimination], in 8-oxo-dG excretion and in the increased resistance of plasma lipoproteins to oxidation in the present study points to a more general relief of oxidative stress after depletion of flavonoid- and ascorbate-rich fruits and vegetables from the diet, contrary to common beliefs."

Want oxidative damage? Munch those flavonoids; and the anthocyanin flavonoids come with the added toxicity of CETP inhibition. Mmmmmm, purple fruit!

High fat diet and fertility

2010-12-12T13:01:00.003Z

Not likely to re establish posting in the next few days (!!!!!) but she is lovely!

Peter

The anacetrapib giggle

2010-11-27T12:34:00.007Z

Stan has a link up to the full text but here is the fun table:

My summary is that a much larger study is desperately needed to confirm that the 300% increase found in cardiovascular mortality is a direct effect of anacetrapib. An even larger study is also urgently required to demonstrate statistical significance for the more modest increase in all cause mortality caused by this drug.

Volunteers should join the queue marked "idiot", unless they are certain that they will get in to the placebo group.

Peter

Still no blogging but this was too fun to skip.

Hepatic extraction of fructose

2010-10-31T06:02:00.015Z

EDIT on 2nd March 2011. This post is incorrect! I'll leave it up as a reminder to myself to check all facts, even when net access is very limited. The pancreas monitors enteric glucose hormonally, not by direct access to the portal vein blood flow. It gets as much or as little fructose exposure as any organ than the liver. Mea culpa. The links are good, so the post has some use still. Thanks to Kurt for catching this one for me. END EDIT

OK, still no posting except for this brief note which is only delivered because the clocks changed, Daniel had a disturbed night and we both have been wake for several hours. Another heavy clinical week to come as of tomorrow... I publish the non-viagra comments on older posts by a brief mouse click but still don't get time to comment back and that will probably apply to this post too. That's just how it is at the moment. Tee hee, probably means there are a ton(ne) of typos in this post too!

Over the last few months I've tried to keep up with my favourite blogs (difficult because work blocks access to all blogs). Many people commented on the fructose and cancer article via Reuters. I'd just like to stick a few observations down about it and about hepatic fructose extraction.

Don over at Primal Wisdom has a nice post discussing the subject and its possible implications. But does fructose feed cancer in vivo? Does it even get to any cancer cells outside the liver and gut?

This led to a follow on post about hepatic fructose extraction, with a nice paper from Japan in Diabetes Care cited. It's unfortunate that ref 11 and ref 13 from this article are both unavailable, even in abstract form. One title specifies investigation of splanchnic blood levels of fructose, which is a very vague term but might include portal vein from gut to liver and might just, if we were lucky, include hepatic vein concentrations, which would allow us to see hepatic extraction rate and systemic penetration.

This would be nice as the second reference's title only seems to specify the role of the liver in the mop-up following intravenous fructose administration. Obviously intravenous fructose bypasses hepatic extraction, so it might not say too much about dietary fructose penetration in to the systemic circulation.

When we look at the micro molar concentrations of fructose (as opposed to milli molar for glucose) in serum as measured in DC article we are looking at venous samples. If the fructose in these samples has come from the diet in the gut it will have been fructose extracted by the liver, then pumped around the body, been fructose extracted by the tissues and only then finally arrived at the sampling needle. It looks like an open question how much fructose comes past the liver and hits the tissues themselves, to feed cancer cells.

You might get more information by measuring the arterial concentration of fructose, as opposed to the venous concentration. Arterial concentration is the hepatic vein fructose diluted in the the full venous return/cardiac output. This would give an indication of hepatic fructose passage without the complication of tissue extraction. But you can't have what's not in the paper and arterial blood samples are a little harder to obtain than venous samples!

EDIT: Cynthia found the abstract to the rat paper. Hepatic extraction is around 50-70%, this dilutes in the venous return but there is still a significant surge through the systemic circulation. This is particularly interesting as humans do metabolise fructose in their muscles, which might just have something to do with systemic as well as hepatic insulin resistance from fructose. I wish I had the time to follow these leads. Abstract text in the first comment. Ta Cynthia. END EDIT

The DC paper does suggest, among several explanations, that the higher venous fructose in diabetics might come from glucose via the polyol pathway. Glucose to sorbitol, sorbitol to fructose. This endogenously generated fructose then drops in to the venous system and gets sampled before going off to liver and/or muscles for metabolism.

So there are a lot of "if"s, "but"s and "maybe"s.

However, the cancer feeding effect of fructose was noted in pancreatic cells. Pancreatic cells sit in the portal vein to monitor gut glucose absorption. They also get hit by the full load of fructose arriving after a couple of cans of soda. It doesn't matter how much fructose the liver extracts if you happen to be a pancreatic cell sitting in the portal blood flow.

You get nuked.

If you are a pancreatic cancer cell you get fed.

Peter

BTW NAFLD has it's parallel in non alcoholic fatty pancreatic disease. Both go from normal through fatty infiltration to chronic inflammation to scarring to neoplasia. Both organs sit in the portal venous drainage from the gut. Another few posts there but...

A heads up

2010-10-15T20:09:00.003Z

Just a brief heads up, especially to people who have emailed me off blog, apologies for the near total lack of replies, there really is no net time worth speaking of at the moment. Too busy cutting and stitching lots of stuff and other things! When we get in to a house of our own things will get back to some semblance of normality but that is not looking like happening in the immediate future.

Peter

Among the many links I've not had time to follow there was this link which I did manage to clicked on and couldn't leave alone. Thanks Elizabeth.

“It’s like an epidemic, in the sense that they’re infected with these wrong ideas, and they’re spreading it to other researchers through journals.”

Hee hee, Ioannidis does meme watching...

von Gierke's disease

2010-09-23T05:32:00.011Z

I'm just taking a quick break from packing boxes and trawling through hepatic insulin resistance related to metabolic syndrome because I got (as always) side tracked. By hepatic glycogen storage this time, rather than lipid storage.

You have to giggle about glycogen storage disease type Ia. It may not be much fun if you have it, but at least you are protected against premature cardiovascular disease.

About von Gierke's disease:

"Glycogen storage disease type Ia (GSD-Ia) is characterized by hypercholesterolemia, hypertriglyceridemia, decreased cholesterol in high density lipoprotein and increased cholesterol in low and very low density lipoprotein fractions."

Of course, with lipids like those, you should die of CVD at a very early age. But you don't.

As people may recall my current hypothesis for the cause of premature CVD is that it is triggered by Purple Spotted sdLDL, something which is NEVER measured by lipidologists. This is hardly surprising because I made it up. Taking a lesson from the lipid hypothesis founders there.

So folks with glycogen storage disease type Ia have the worst possible lipid profile you can imagine and no premature CVD.

To explain this paradox (gasp in awe at the explanations) you can look at antioxidants like uric acid or do very clever things with cholesterol efflux mediators or hypothesise about adiponectin. Take your pick.

Guess what. People with glycogen storage disease type Ia are virtually never hyperglycaemic or hyperinsulinaemic. In fact hypoglycaemia can be a serious problem for them. But they don't get heart disease. Funny that.

Oh, and they are told to avoid fructose too (haven't checked why, but it seems like a good idea)... Perhaps I'm wrong about Purple Spotted sdLDL, it could just be that it's made of fructose rather than sucrose!

Peter

Fathead Supersize Me and Sweden (2)

2010-09-18T12:41:00.008Z

An addendum to the mouse trans fat fibrosis paper: It's junk. Utter junk. Even the title is wrong. There are NO trans fats in the experiment, NONE what so ever!

The mice were fed on the Surwit Diet. Here's the pdf from Research Diets.

I thought medium chain trans fats were a bit of a strange animal....

So the mice are being fed on fully hydrogenated coconut oil, which has minimal PUFA to begin with and gets hydrogenated to fully saturated, mostly medium chain triglycerides. Plus non hydrogenated soya oil, which is mostly omega 6 PUFA and a little omega 3 PUFA.

The ONLY source of carbohydrate in the diet was sucrose and maltodextrin, which made up 25% of calories. To which they added sucrose in the drinking water, plus added fructose in the drinking water.

THERE ARE NO TRANS FATS IN THIS DIET.

Fructose, beyond human comprehension, with adequate soya oil, is enough to fibrose a mouse's liver. Not even Bill Clinton could eat this much fructose a day for life.

Who scrutineered this paper? Who wrote the title? How much money was wasted? What is happening in the world?

Arghhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh!

Ouch. Ouch. Ouch.

Ouch.

I'm trying to stop banging my head on the table but (Ouch)......

Peter

Fathead, Supersize Me and Sweden

2010-09-16T05:36:00.027Z

I generally ignored this paper in 2008 as it didn't look particularly interesting and seemed mostly about fast food bashing, where the fast food included a large amount of sugar and starch. A bit like a real life Supersize Me, but with genuine average food intakes provided and individual responses in ALT levels, a marker traditionally associated with liver damage, also provided.

If anyone wants to eat 285g of sugar a day then they deserve whatever they have coming to them. What they have coming is an ALT increase which correlates with either carbohydrate or sugar intake by three weeks in to the feast. Not with fat.

I found the lack of association with fat disappointing. Sweden is a country fairly replete with trans fat and a little arithmetic applied to Table 1 (LeenaS describes these as "hidden fats") suggests that trans fat intake went from about 6g/d to 24g/d during the over feeding period of the study. This is not quite at the level of Crisco poisoning but I was still disappointed to see no discernible association with ALT. Ah well, you can't have everything.

Now I remember Tom Naughton nuking himself with trans fats during Fathead to the point of lowering his HDL, but otherwise he developed no suggestion of metabolic syndrome. But then Tom engaged his brain before drinking bucket loads of fructose and desisted from such stupidity. The fructose trick is for anyone with more Spurlockian intelligence.

To go back to Sweden: Gross overfeeding with "fast food" elevates your ALT. This is sort of boring because no one in their right mind is going to eat that much fructose in a month, which sort of defines Spurlock.

But was anyone still awake by the end of Supersize Me? Remember how long it took him to lose weight on his girlfriend's vegan cooking?

Now the question is, does this translate across in to the Swedish ovefeeding group? Well that was answered by a follow on study looking at the participants two and a half years down the road.

They're still fat. On average.

Something breaks in a month of overfeeding with trans fats and sugar. That is fascinating. Now you could argue that the volunteers got the taste for junk food, that their fat cells got stretched, that they were already self selected for being comfortable with gaining weight to take part in the study etc. I'd like to look a little more closely at liver pathology.

Elevated ALT is traditionally assumed to indicate liver damage. But there might be circumstances where you make more ALT in each cell, especially if a lot of amino acid processing is going on, so get benign ALT elevation. No one had a liver biopsy so it was impossible to find out exactly why the ALT went up.

Now, from a pathologist's point of view, a fatty liver is completely reversible. There is nothing permanently damaged in each hepatocyte or in the structure of the liver. Hepatic inflammation is also theoretically reversible. Those old leucocytes can leg it out just as easily as they legged it in.

But fibrosis, that's a different matter. Fibrosis is there to stay. This is at the micro architectural level. We're not talking cirrhosis (yet). No pathologist expects a fibrosed liver to go back to normal. It may adapt, regenerate, keep you alive, yes. But it's not normal. It will never be normal.

I picked up a link to a mouse study in which they fed chow, Super Crisco (medium chain trans fats, what are they?) or Super Crisco plus fructose enriched sucrose via the drinking water. The rest of the diet is not in the abstract so who knows what else they did. But it was the Super Crisco plus fructose/sucrose in the drinking water which made all of the headlines.

Super Crisco appears to be bad for your waistline but may not, on its own, produce the irreversible changes in the liver seen in the mice who combined it with HFCS. As far as you can tell from the abstract.

A diet replete in trans fats and HFCS fibroses your liver.

Translating from the Swedish volunteers and these poisoned mice to our two film directors:

Tom Naughton should be fine with his low fructose high trans fat diet and Spurlock should have aged his liver by a few years (in terns of insulin sensitivity) during his month of self poisoning on trans fats because he combined them with fructose to push his ALT through the roof.

I'll try and put this in to a physiology context when a little more time comes my way.

Peter

BTW: A methodological note from the initial Swedish study which adds the "human element" to the mind set of the "scientists" running it:

"If the subject was not able or willing to ingest the hamburger-based diet at any stage, it was changed to whatever food the participant accepted with the highest priority to achieve the calculated caloric intake and also, if the study subject still found it acceptable, a diet rich in protein and saturated animal fat."

My emphasis.

As always, it's nice when people nail their colours to the mast.

I see from Table 1 in the follow-on study that one man and one woman had actually reduced their weight to below their pre study weight by 2.5 years. I just wonder whether they were the ones who refused the trans fats of the hamburger diet and went with animal fat and protein to source their excess calories. No one is saying.

That human element gets everywhere!

EDIT: See Patrick's notes in the comments about the group leader from the hyperalimentation studies. A different impression from the published papers. There is hope for Sweden. Good.

Axen, Axen (3) and Hawks

2010-09-14T08:59:00.008Z

John Hawks put up this excellent quote in his post James Randi on scientists

From Randi, J. 1988. "The detection of fraud and fakery." Cell Mol Life Sci 44:287-288:

"Scientists are very easily deceived. They think logically, extrapolate possibilities from evidence presented, assume (with a good probability of being right) certain aspects of the observed data and draw upon their past experience in coming to decisions. This is to say that they act very much as all humans do, struggling with sensory input to derive new facts from it. But scientists do this with a certain authority and certainty born of their training and discipline. They are thus excellent candidates for being flimflammed by a clever operator who is aware of the fact that scientists seldom bring the human element into account."

Axen and Axen do not do either fraud or fakery. Their data are real. But the human element is essential.

Peter

Axen and Axen (2)

2010-09-01T10:04:00.049Z

OK, the biggest mistakes in A&A's 2006 paper was, in my book, Atkins bashing. There, I am biased. Citing the Atkins Diet specifically and using this citation as the basis for their study design is problematic. I don't know if A&A ever read ref 1 as cited but, believe me, these rats were not on the Atkins Induction or the subsequent Ongoing Weight Loss phases. Generally the Atkins diet involves Food plus artificial sweeteners and some easily avoidable non-foods such as soy flour. And vegetables.

So what did they do? They took a group of lab rats and made them obese with trans fatty acid enriched Crisco as 60% of their calories. They then split the rats in to two groups, one was given 60% of calories as carbohydrate through out. The other group was given 5% carbohydrate for 2 weeks then 15% carbohydrate for a month, à la Atkins. Both groups were moderately energy restricted, dictated by a somewhat random decision protocol.

There was a parallel group eating crapinabag (CIAB) throughout (no Crisco). Glucose tolerance tests, with insulin measured at 20 minutes, were performed at various time points.

What went wrong in 2006?

Things started well with the Crisco rats having higher blood glucose at 10 minutes in to the GTT than the CIAB rats. Insulin levels were a lot higher in the Criso rats 20 minutes in to the test by which time glucose was identical between Crisco and CIAB groups. That's Graph A. Crisco causes insulin resistance.

Things were going reasonably well for Atkins bashing at the end of the two week "Atkins Induction" phase. During GTT the 60% carb group were slightly lower in glucose and this made p<0.05 at 10 minutes. However the cracks are beginning to show. The "Atkins Induction" group had an insulin at 20 minutes in to GTT of 600pM, the 60% carb group needed an insulin of over 900pM to achieve the marginally lower glucose level at this point. The insulin values were, luckily for A&A, not significantly different. Fasting insulin at this point was also lower in the "Atkins Induction" group. A&A were lucky on the p values here too. Here's graph B with that spiked glucose at 10 minutes:

By the end of the experiment at 14 weeks the Atkins Group had been given more (15% of calories) carbohydrate. The GTT at this time point is shown here:

Now you need to get your glasses on for this one. Can you see any difference between the "Atkins Ongoing Weight Loss" (VLC) group and the 60% carbohydrate (HC) weight loss groups? No? Me neither.

Insulin values were slightly better in the 60% carb group but again nothing significant. Both weight loss groups had lower insulin values than the CIAB group! All NS again.

So there we have it: Atkins Ongoing Weight Loss, as interpreted by A&A, gives a GTT curve which is superimposed on the 60% carbohydrate weight loss group. ATKINS is GOOD!

There is a load of bollocks in the discussion about the impaired insulin response in the Atkins group in graph B. To me shifting glucose with a lower insulin level is good, not bad. The spike at 10 minutes is the only saving grace to the funding generating ability of this study.

But graph C is just hysterical.

Okay, A&A are not stupid. They worked out exactly what went wrong in graph C and what was going well in graph B.

So they went out and got more funding to demonstrate CONCLUSIVELY that the Atkins Diet makes you diabetic. They got that funding. These people are good, make no mistake. They got the desired result second time round. How many people get a second chance like this? They published in 2010.

Here is graph a from 2010, directly comparable to graph A from 2006.

Very similar but tidied up in 4 years of refining the model. Or maybe the CIAB has been improved. Anyhoo, same result. Crisco does nasty things to GTT curves.

Next is graph b, which is like graph B above but is after a month rather than 2 weeks and has the on going Crisco group included. The very low carbohydrate group is looking a lot like the Crisco group by now...

But here is the Money Shot in graph c from 2010. Just look at the Crisco curve (HF) and the 5% carbohydrate (VLC) curve. Just look at that fit!

I told you these people were good!

But also go back and look at the blooper graph C from 2006.

So what is going on?

There is a nice pointer in line seven of Table 2, "Soleus TAG". This is the amount of intra myocyte lipid in a typical muscle. It is a marker of how reluctant that muscle is going to be to accept glucose. Two groups have high soleus TAG. The Crisco poisoned (HF) group throughout and the VLC group at 16 weeks.

The explanations for why these two groups have high soleus TAG is likely to be different. Both will, in all certainty, reflect elevated FFAs in the plasma. But the Crisco poisoned group will have elevated FFAs, 24/7, despite 15% of calories as starch. We know from the 2006 blooper that 15% of calories as starch will give a GTT curve in VLC rats which matches the 60% carb group EXACTLY. Not so if you are Crisco poisoned.

The VLC rats on 5% of carbs will have elevated FFAs 24/7 because they would be dead without them. They are on a starvation diet of which only 5% is carbs. Without FFAs they would run their muscles on glucose. They don't get enough glucose per day to do this and still keep their brain alive. Death is not an option.

So the Crisco group has elevated TAG in soleus muscle in the presence of carbohydrate in the diet. It's pathological. The VLC group has elevated TAG in their soleus muscle because they had minimal free glucose available, which is physiological.

BTW either fasting or a brief period without carbohydrate will promptly elevate muscle TAG in humans. It is an utterly normal response to a reduced supply of glucose. The actual signal for muscle insulin resistance is not likley to be the tri acyl glycerol molecules themselves because athletes have bucket loads of this without insulin resistance. More likely is a more ephermeral moiety such as Acyl-CoA molecules or diglycerides which more closely reflect FFA supply. In a GTT the glucose supply is massively supraphysiological. For insulin sensitivity to return to LC muscles it takes time for insulin to spike, insulin to get to adipocytes, adipocytes to respond to insulin, FFA level in blood to drop and FFA derivative level in muscle to drop. It's hardly surprising that the 10 minute glucose peak was higher in the VLC rats during GTT. However, as soon as the muscles clear FFA derivatives they are still geared up to go with glucose, nae problem, nae bother. I'll come on to issues with insulin later. Obviously the Crisco poisoned rats are obese and their adipocytes will have an inability to suppress FFA release in response to insulin. That's how it is if you eat Crisco.

Let's look at the insulin responses. All of the fasting insulin levels were about the same. Obviously the VLC had the lowest insulin and almost certainly the lowest HOMA score although p might still have been > 0.05. By week 16 the insulin response to GTT was interesting.

The VLC rats mimicked the Crisco (HF) group's glucose curve. But they did it with just 1.79ng/ml of insulin. The Crisco rats needed 2.93ng/ml of insulin (p<0.05). The lower curve with open diamonds is the 60% carb group. The curve looks good until you realise that these rats needed as much insulin as the Crisco rats to achieve this beautiful curve, nearly twice that in the VLC group (2.95ng/ml vs 1.79ng/ml, p<0.05).

So which rats are the most insulin sensitive? Not the Crisco rats. I'll accept that. Just say no to Crisco... It is completely arguable between the VCL and 60% carb group.

BUT. What would have happened if the VLC group had produced the same insulin response as the 60% carb group? Impossible, scream Axen and Axen. The VCL group have a blunted insulin response. It makes them well on the road to diabetes, metabolic syndrome, blindness, dialysis, we need the funding...

Calm down Peter, bit OTT there!

Except metabolic syndrome is characterised by elevated insulin, not depressed insulin. Duh.

I have to thank Helen who placed a comment on another post. She pointed out that glucokinase in the pancreas, the enzyme which the pancreas uses to sense glucose in the portal blood, is down regulated in response to carbohydrate restriction. Oh.

It is, err, up regulated in carbohydrate surplus.

This is what "bit" Axen and Axen in 2006. It looks like 15% of calories as carbohydrate in a VLC non-Crisco situation is adequate (on a high protein background) to allow pancreatic insulin secretion in response to glucose to become identical to that produced by rats on a 60% carbohydrate diet. Muscle TAG and associated molecules will drop too. Hence the overlay of the GTT curves in 2006.

Let us assume, very reasonably, that the VLC rats in 2010, on a 5% carb, energy restricted diet, are not expecting to deal with hyperglycaemia any time soon. They down regulate glucokinase production. Then some joker injects 1g/kg of glucose in to their peritoneal cavity. No one up regulates their glucokinase in 10 minutes, not even Super Rat*. Insulin response is blunted. Hyperglycaemia results.

*Actually Super Rat could do this but she is always busy saving the planet (again) and doesn't have time to help out here.

What would have happened with a few days carb loading in the VLC group before the GTT? Well, we (that "we" includes A&A) know the answer to this from 2006. Did you really think A&A are stupid? How many times do I have to point out that these people are good. Very, very good. They know that to get a "bad" result for VLC you must NOT increase carbs pre glucose load in a GTT.

Does anyone think that neither Axen nor Axen has heard of glucokinase? That would mean they're stupid. They're not, they know that if they allowed 15% carbs for a few days the VLC group would overlay the curve of the 60% carb group. For crying out loud, they published the damned curves themselves!

No. The effect of increased carbs on a VLC is not "unclear" (their word). It adjusts pancreatic insulin secretion to deal with carbs when carbs form a significant part of the diet. That's called physiology!

In summary:

Do A&A have a paradigm to support, a mortgage or two to pay, a living to make, careers to develop?

A few fatties getting injured is of no concern, provided the models can be adjusted to keep the funding coming through.

Will people edging towards type 2 diabetes get injured by a very low carbohydrate diet or will they be injured by A&A's funding success? What if they eat low fat high carbohydrate in the real world? What is hunger?

You decide. Then go eat some fat.

Peter

But not Crisco. Just say no....

Here we go again

2010-08-26T09:58:00.002Z

There might not be a lot of posts over the next few months. I'll get Axen and Axen (2) posted when I can!

Axen and Axen (1)

2010-08-21T13:22:00.017Z

Okay, the one without the chocolate all over their face is Ratty. He, Ratty, is 20 weeks old and weighs 360g. He is slim, active, well muscled (for a rat) and, of course, eats a very high fat diet. In fact he eats exactly the same food as we do with extra fried belly pork and cheese to snack on between meals of scrambled egg yolks (in butter), Bolognaise sauce, chilli mix or beef stew, should he ever get hungry between those main meals. My wife gave him a grape once. I removed it from his cage when it went mouldy.

I don't think he has metabolic syndrome. He eats an ad lib diet which provides about 70% of his calories from fat.

Now, I was looking through Axen and Axen's 2010 paper on managing metabolic syndrome in rats. First you have to make them obese. Hmmmm, now how might you do that? Ah ha! A high fat diet. In fact just 60% of calories will do the trick. Wow. Lets look at Table 1, column 2, HF diet used to induce obesity in rats. There it is: 60% fat, 25% protein and a mystery 15% carbohydrate.

Plus this line in the methods:

"The contents of saturated: monounsaturated: polyunsaturated fats were 25.3%:43.3%:31.3% in the HF diet and 31.7%:42.7%:25.5% in the VLC and HC diets (ω-3 fatty acids comprised ~2% of total fat)."

OK, are you thinking the carbohydrate was sucrose? Me too. Wrong! But the fat was supplied by Proctor and Gamble.

If you work through the paper to find out how this obesogenic diet was developed you get to ref 9, which is Axen and Axen again, this time in 2006. Once again, Table 1 for diet composition:

This tells us nothing more about the obesity diet (it's not really what the paper is about) but the fat was supplied by Proctor and Gamble. The paper does have another reference about the obesogenic diet, number 13 this time, which leads us to a gem from another Axen paper, just Kathleen and friends this time:

This is the sort of paper I love. Here is the abstract from 2003.

I think I have to put it here in full as it is really too important to summarise. They have a diet which develops metabolic syndrome in rats which CANNOT be prevented by restricting calories to normal body weight. Has any one heard of the "slim but metabolically obese" concept? The skinny type 2 diabetic? Kathleen Axen knows EXACTLY how to produce a skinny type 2 diabetic rat! And this is the paper. And here is the abstract:

"High fat, low carbohydrate diets are popularly advocated for weight loss and improvement in metabolic Syndrome X, a constellation of risk factors for type 2 diabetes mellitus and cardiovascular disease. The effects of an energy-restricted (to prevent weight gain in excess of normal growth) high fat (60% of energy), low carbohydrate (15%) diet were assessed in both lean rats and in rats previously rendered obese through ad libitum consumption of the same high fat diet. In obese rats, restriction of intake failed to improve impaired glucose tolerance, hyperinsulinemia, and hypertriglyceridemia, although it lowered visceral fat mass, liver lipid content and in vitro insulin hypersecretion compared with rats continuing to consume the high fat diet ad libitum. In lean rats, restricted intake of the high fat diet impaired glucose tolerance and increased visceral fat mass and liver lipid content. These findings support the conclusion that, in the absence of weight loss, a high fat, low carbohydrate diet not only may be ineffective in decreasing risk factors for cardiovascular disease and type 2 diabetes but may promote the development of disease in previously lower risk, nonobese individuals."

I think that that's pretty conclusive. A diet of 60% fat makes a rat glucose intolerant even if you starve it (and rats in the starved group will be HUNGRY, unlike Ratty) to a normal bodyweight. And no sucrose in sight. High fat and restricted carbohydrate diets might PROMOTE type two diabetes in rats (and people?) and give them heart attacks (do rats have heart attacks?) even if they were slim to begin with and stay slim on the diet. That's me and Ratty all right.

Ratty and I are doomed to diabetes it appears.

BTW, did I mention that Proctor and Gamble provided the fat?

Which fat? Well, here's the section which never made it in to the abstract:

"the other group was fed a high fat (HF;347 g fat/kg diet) low carbohydrate diet (22.6 kJ/g, 5.4 kcal/g). The HF diet was comprised of powdered Purina 5001 and hydrogenated vegetable fat (Proctor & Gamble, Cincinnati OH), with casein, L-methionine, AIN vitamin mix, and AIN mineral mix (Bio-serv, Frenchtown, NJ) (17) added to provide equivalent protein concentrations (LF, 234 g/kg diet; HF, 331 g/kg diet) and equivalent vitamin and mineral contents for the two diets. The hydrogenated vegetable fat contained 25% long-chain saturated, 44% monounsaturated and 28% PUFA, with 17% of total fat as trans fatty acids (manufacturer’s communication). This high fat, low carbohydrate diet was used because of the more pronounced obesity it has produced in rats in our laboratory than have several commercial high fat diets."

Stop, rewind, slow frame:

"with 17% of total fat as trans fatty acids"

That's a very special fat. Magic fat. Unless I am very much mistaken Proctor and Gamble make commercial bootpolish marketed as fit for human consumption. I think it's called Crisco. They have been poisoning America with it for decades.

DO NOT, UNDER ANY CIRCUMSTANCES, BASE YOUR DIET ON 60% OF CALORIES FROM FAT WHICH INCLUDES 17% TRANS FATTY ACIDS.

DO NOT DO IT.

Just say no.

But oh, oh, oh, Kathleen, why did you leave this out of the abstract????????????

People will think that eating fat makes you fat......

It certainly will if Proctor and Gamble supplied it.

Peter

OK, the 2006 and 2010 studies need looking at next in some detail. They are really quite funny in combination. Also, to give K Axen her due she does discuss trans fat toxicity extensively in the discussion of the paper. But not the abstract. There it's "fat" all the way. A pinguid diet (for Gary; ok do I win at Scrabble now?).

Actually, re reading the last sentence of the abstract: This is a very unpleasant piece of writing. Would people go as far as the full text to read what the paper is actually about?

Thoughts on problems with high fat diets

2010-08-21T12:25:00.008Z

Back comments section of the uric acid post _Flo passed on the news of the death, due to stomach cancer, of a prominent long term Optimal Diet follower. This is not the sort of in formation that should be ignored although, from an individual case, I doubt whether there is anything we will every actually find out about causation. The main thing it brings home forcefully is that none of us is immortal and a good diet will not allow us to automatically reach an advanced age. The OD and similar approaches brings marked improvement in many of the diseases of civilisation but clearly not all. For someone who has achieved remission from multiple sclerosis or ankylosing spondylitis it is depressing to accept that those same diet changes might not be cancer protective, or not completely so.

_Flo has made her own modifications to her diet which are sensible in their own right and represent her choices. As regards the type of cancer it quite interesting to note that Poland has one of the highest rates of stomach cancer in the world. This snippet was passed along by another friend on the net and is corroborated by pubmed. It does suggest that speculation based on the location/type of the tumour may not be representative a specific diet related factor, rather the result of living in Poland. Of course it might be diet related.

I have my own personal tweaks to the OD and do not see any clear way of improving what I have already achieved.

So let be set here in print. No one has all of the answers.

I thought I would take this chance to discuss the possibility that there are people for whom low carbohydrate eating might be genuinely problematic. I have picked up a couple of hints along these lines over the years, so here we go with some thoughts.

I discussed a secondary prevention trial for heart disease here. All of these people had glucose regulation problems (that's part of my definition of having a heart attack). Adding 500-600kcal of either corn or olive oil to a very low fat diet precipitated diabetes in two of these individuals. Why? That's a good question. Type two diabetes is intrinsically linked to insulin resistance. Normally people eating a bolus of fat will reduce the rest of their calorie intake to compensate. Anyone who didn't would have placed a significant carbohydrate load on top of fat induced insulin resistance (even vegetable oils induce this, although palmitic acid does a rather better job) and failed to deal with their relatively high carbohydrate intake. Pure speculation but a low fat diet, with 80ml of added vegetable oil, undoubtedly triggered 2 cases of type two diabetes. I found that interesting.

Second hint was Jenny Ruhl's comment that she had come across very, very occasional individuals with diabetes who responded to low carbohydrate eating by deterioration of glycaemic control. Again, I have no details what so ever but anyone's ears should prick up when they hear things like this. Denial is not where it's at.

Then Carb Sane introduced me to the Otsuka Long-Evans Tokushima Fatty strain (OLETF) of rats. These rats are a diabetologists dream. Under fixed isocaloric conditions they gain weight and fat mass in direct proportion to the percentage of fat in an exactly measured 28.7 joule daily ration. Like, wow. Fat really does make you fat!

Of course the OLETF rat is described as a Good Model for human type two diabetes. It explains exactly why all diabetics put on to a LC, high fat diet become obese and hyperglycaemiac. What do you mean, they don't? Oh, not enough testosterone! The OLETF rats only become diabetic if they are male. That's why all type two diabetics are blokes. What do you mean, women get type two diabetes? But out model says only blokes should. And it's a Good Model...

OK facetiousness aside, what is happening in the OLETF rats? Is it possible that there are some humans out there with OLEFT rat style type two diabetes. Well, why not?

Let's have a look at what is happening from the point of view that insulin is the primary hormone in the development of obesity. If you think about someone eating just once a day, essentially all of their calories are going to get stored. Glycogen in the liver and fat in the fat. What determines weight gain is how much of that stored energy fails to be extracted from storage before the next meal arrives.

Summary: No one stores lipids or glucose in their blood stream. It all goes in to short term storage. What comes out determines weight loss. Insulin determines what comes out.

OLETF rats, on high fat, fixed calorie diet of 28.7 joules per day put all of this energy in to storage but fail to extract as many of these calories/joules from storage as those OLETF rats on 28.7 joules of a high starch diet. What is going on?

If you accept the insulin hypothesis of weight gain, the answer is that dietary fat is being trapped in adipocytes by excessive blood insulin. There must be excess insulin.

Why is the insulin elevated when there is a reduced dietary stimulus for insulin production? These rats have peripheral, almost certainly muscle based, insulin resistance. But only on a high fat diet.

High fat diets put lipids in to muscles, muscles full of lipid don't accept glucose. If the system works correctly the muscles run on lipids until there is a balance between fat supply rejecting glucose and fat depletion allowing glucose acceptance. A few billion years is ample time to get this system working correctly to maintain normoglycaemia in the face of varied macronutrient intakes from day to day.

What might be broken in this system in the OLETF rat?

Well, if you can get lipids in to muscle cells but cannot then use that lipid for beta oxidation you would expect to develop muscle insulin resistance in proportion to the amount of fat you supply, ie if the fat enters the muscles but does not go any further those muscles will become insulin resistant and stay insulin resistant. If muscles are not accepting glucose because they are insulin resistant the glucose is going to have to be dealt with by increased levels of insulin. Hyperglycaemia is unacceptable.

The extra insulin needed to maintain normoglycaemia then traps stored dietary fat in adipocytes. The rats get fat because they cannot get fat out of adipocytes. They will also do less running around and will probably feel colder than normal rats because they have no access to their fatty tissue for energy supplies. If they had access to food they would eat more, but 28.7 joules per day was the limit in this experiment. If they had access to more calories they would clearly eat more because no one likes the hunger and shivering produced by sequestering a chunk of your caloric fat intake in your adipocytes and locking it in there with insulin.

Once your fat cells get full enough they will spill free fatty acids because they are now too full to listen to insulin any more. These FFAs join those intra cellular muscle tissue di and tri glycerides from the metabolic defect. Intra myocyte fatty acids still have no where to go, so muscle insulin resistance rockets, plasma glucose rockets and you have a superb model of fat induced obesity and peripheral insulin resistance.

Glucose enters mitochondria as pyruvate. Fatty acids enter mitochondria as acyl CoA moieties. The place to be looking for explanations for the syndrome seen in the OLETF rat is in fatty acid processing. My guess is that lipid molecules get in to myocytes but never get effectively passed to the mitochondria. Quite what testosterone has to do with this is beyond me, it's not me that is suggesting the OLETF rat is a good model for human type 2 diabetes!

You have to ask what would have happened on a ketogenic diet. Would ketosis have side stepped this problem? Ketone bodies enter mitochondria without any need for long chain fatty acid transporters. They use monocarboxylate transporters, just like pyruvate... You don't really think that Kaneko et al would so something as stupid as putting an OLETF rat on a ketogenic diet? But it would have been interesting. I'm not sure it would side step the problem but it might. I'm certainly not expecting a diabetologist to find out for me.

I really enjoyed the OLETF rat. Does it tell me something about type two diabetes? Only that there might be very, very special people who respond to dietary fat with hyperglycaemia.

I never did find any teeth in my chickens. I understand hen's teeth are rare. So are OLETF humans.

But they probably exist (not the hen's teeth!).

Peter

Urate, ascorbate, resveratrol and land mines

2010-08-06T04:45:00.026Z

It only needs a brief glance through the literature to realise that uric acid is a prime mover in metabolic syndrome and might reasonably compete with cholesterol as the premier mammalian-synthesised molecule of self destruction.

Until of course you come across interesting papers like this one which suggests that uric acid is a signal of tissue injury, a mobiliser of repair systems and, in particular, a recruiter of endothelial progenitor cells.

In modern terms, stepping on a land-mine will produce a surge of uric acid to blunt the effects of the renal ischaemia which will occur as you bleed out through the remains of where your foot used to be. In evolutionary terms you can see how surviving acute trauma might be beneficial and it looks like uric acid is seriously useful in this context. Stepping on a land mine every day fairly rapidly becomes problematic in terms of all cause mortality and even uric acid is unlikely to maintain its efficacy with prolonged usage. Chronic drug induced hyper uricaemia appears to be a Bad Thing in that it blunts the benefits of acute elevations.

If you don't live in a heavily land-mined country you are (a) lucky and (b) more likely to be injured by a bottle of cola or a bowl of apples. Or maybe oranges, stawberries, kiwis etc. Whether it is simply the fructose in the cola or some other plant nasty in the fruit in addition to fructose isn't particularly clear. But your body produces a spike of uric acid in response. It's been injured.

It is perfectly possible to consume cola or fruit on a chronic basis without the immediately obvious effects of repeatedly treading on a land mine.

This leads me to whether there are direct benefits from minor damage of eating fruit via hormesis or whether it is just all bad. I suspect it depends on the dose and the chronicity. When you look at WHEL and PPT there may well be some sort of accommodation which leaves total mortality unchanged by eight years of eating extra fruit and veg. There seems to be little doubt that an acute rise in uric acid is beneficial and chronically elevated uric acid may be less so. This flies in the face of Kwasniewski's opinions about uric acid, the more the better. But he is talking about elevated uric acid in a LC high saturated fat situation, not after eating a bowl of apples a day for a few years.... Of course he never cites references but I'm keeping an eye out!

Ascorbate is interesting as it is a rather ubiquitous antioxidant and does appear to be used by humans for assorted essential functions, all be it in very small amounts, despite the fact we cannot synthesise it. Most mammals tightly regulate their ascorbate production to their needs as they can produce it on demand. Not so humans. We don't produce it and our intake is completely random, varying from 10mg per day or less on an all meat diet to a few 1000mgs if you fall face down in a clump of cranberries and keep eating all day.

The chances of you meeting the cranberries every day for six weeks are slim, so if you want to study the effect of relatively high doses of ascorbate on free radical mediated processes in humans you have to use supplements. Eating 1000mg represents an awful lot of berries but is a common supplement dose.

This group in Spain actually pre empted the group in Germany in demonstrating the adverse effects of ascorbate supplementation on the effects of exercise.

Exercise produces free radicals, free radicals signal for both muscle cell division and mitochondrial number increase (using the surrogate of cytochrome C for mitochondrial number).

If you dose with 1000mg ascorbate daily you will scavenge the free radicals and blunt the increase in both muscle mass and mitochondrial number which should have been generated by those free radicals. You might expect this and it's worth noting that the effect appears to clearly detectable but far from complete.

I have worked on the assumption that taking antioxidants should down regulate your own endogenous antioxidant production. The Spanish group used rats for this part of their research and did indeed find that gene expression for synthesis of both superoxide dismutase and glutathione peroxidase are markedly down regulated. A zero increase with ascorbate supplemented exercise compared to a 3.5 fold increase after three weeks of unsupplemented exercise.

Think of the implications. You exercise, exercise generates free radicals, free radicals build muscle and upregulate production of antioxidant enzymes. So exercise is, fundamentally, antioxidant (while ever it is kept within the limits which can be accommodated by synthesis of SOD and GPx). Obviously ultra-marathon runners must be willing to injure themselves for their sport.

Mega dosing with ascorbate markedly blunts the induction of the intrinsic antioxidant system of mammals, even of a rat which naturally produces ascorbate.

What about resveratrol? Feed it to a mouse in quantities equivalent to between 150 and 1,500 bottles of wine a day and you get some improvement in inflammatory markers. Do you simultaneously down regulate SOD and GPx synthesis? Now there is a question!

That will be a cracking study. The answer will be yes if resveratrol really scavenges significant numbers free radicals. Our own endogenous antioxidant systems are fine tuned to our needs. What does a blanket treatment with a highly potent antioxidant do to our ability to respond to the daily alterations in free radicals? Free radicals carry information. How do we replace the information lost if they are stuck to a resveratrol molecule?

Luckily our bodies try hard not to absorb the stuff and normally metabolise it to sulphated or glucuronated forms within minutes. It's unlikely that we ever have much free resveratrol (or dark chocolate favanoids either, phew) in our bloodstream until human ingenuity invented the resveratrol chewing gum.

Unintended consequences anyone?

Peter

BTW The Wiki article on resveratrol appears to be very contentious. Wiki becomes a battleground once you get on to sticky subjects like cholesterol and, apparently, resveratrol. I've kept the text for when it gets edited to "Resveratrol explains the French paradox and will make us live for ever"

What's the secret of time travel doing on Fry's ass?

2010-08-01T19:23:00.009Z

I would just like to paraphrase that relevant line from Futurama:

What's the secret of Eternal Youth doing on a grapeskin? It was bound to be somewhere..........

Resveratrol. Gift of plants. Oh oh, wrong again!

Many thanks to Blogblog for the link to that hysterical abstract, I just love it. If anyone thinks that resveratrol is the answer to the French Paradox, or that there even is a French Paradox, or that plants will gift us eternal youth, then you're in the wrong place on the net I'm afraid, just hit the back button!

Peter

My penance for cribbing 7.9 seconds from the Futurama movie: "Buy it, buyyyyyyy it......."

Fruit and vegetables (12) WHEL and CVD

2010-07-28T12:39:00.006Z

I just thought I'd have a quick look (after viewing the PPT trawls) at the data trawls from WHEL in case they'd looked at the effect of a diet high in fruit 'n' fibre and low in fat on CVD. Of course they did. It gets kind of boring trotting out these bias confirming studies, but here's the punchline anyway:

"Over a mean of 8.1 years, a dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women..."

Maybe they need more cream on the fruit? I'm just so grateful that they didn't get anything correct by accident. WHEL and PPT are such great sorces of hard data on crap diets.

Peter

Jimmy Moore on Dr Weil

2010-07-26T12:34:00.003Z

Another one liner in case you don't follow Jimmy Moore, the post on Dr Weil is very interesting from the political point of view. Very interesting.

Peter

Wheat and lactase

2010-07-25T09:40:00.021Z

While I'm trying to clear my desk top a little, with limited access to the net during an oncall weekend, I thought I might post this link as I'm thinking wheat at the moment.

I think I've discussed the role of gluten in trashing the brush border cells, again without need for any sort of immune system involvement. The present study did involve immune-injured people but I see no reason why exactly the same principle shouldn't apply to antibody negative "coeliacs" (suffering from "imagination" or even, gasp, orthorexia nervosa, another from Elizabeth. Apologies for the picture of the bowl of rabbit food).

Another aspect of normalising the brush border is that far less food is going to be left in the small intestine to feed a bacterial overgrowth. On a LC, low fibre diet there are likely to be massive changes in gut flora. I have an anecdote from several years ago given to me by a lady and her mother who had gone LC plus gluten free and, after quite some time, both suddenly became lactose intolerant. This is the last thing I would have expected.

Now, I'm no great enthusiast for pre- or pro-biotics, but I do eat a fair amount of cheese, soured cream and high fat yogurt. The last of those occasionally in large amounts. So eating real-food dairy accidentally includes plenty of germs. Germs to which we are well adapted. Gut bacteria are normal to humans and lactobacilli are amongst the first bacteria to colonise the gut of a healthy infant, presumably because its mother provides lactose (and pre-biotics too, hmmmm). For humans who are not genetically adapted to adult lactose intake, are we borrowing the gene for lactose tolerance from the microbiome in our gut? Is it possible to lose lactose tolerance if we lose lactobacilli during the major bacterial starve-out that LC probably produces?

Alternatively, as coeliac disease appear to require certain bacteria, does lactose intolerance REQUIRE certain non-lactobacilli bacteria? This would fit better with two people developing lactose intolerance at the same time in the same household, if they simultaneously picked up the same bacterial opportunist.

Answers on a postcard to........

Peter

Wheat Germ Agglutinin; how little is enough?

2010-07-25T08:13:00.009Z

Chignola's group have been at WGA again. Their basic interest is (was?) in using WGA as a drug carrier aimed at certain cell surface sugar groupings, hoping to target certain cancers, as far as I can see.

Their first paper in 2005 demonstrated direct intestinal cell toxicity at micro molar concentrations. However Glenn updated me on their more recent 2009 paper here:

"At nanomolar concentrations WGA stimulates the synthesis of pro-inflammatory cytokines and thus the biological activity of WGA should be reconsidered by taking into account the effects of WGA on the immune system at the gastrointestinal interface. These results shed new light onto the molecular mechanisms underlying the onset of gastrointestinal disorders observed in vivo upon dietary intake of wheat-based foods"

Notice there is no mention of coeliac disease, you do not need to be genetically predisposed by HLA type to have WGA toxicity. This looks to be yet more direct molecular toxicity.

Now we are talking nanomolar concentrations.

It's a bit difficult to get your head round a nanomole of WGA. One mole is the molecular weight expressed in grams. For WGA this is a BIG number of grams. A nanomole is not very much. So a nanomole is not very much of quite a lot of grams! Without struggling with the math I'd just suggest putting the bread in the bin and seeing if I could get out of my wheelchair as my gut integrity improved! An angry immune cell, looking at a soup of gut peptides, is not going to care what collateral damage it does.

Peter

BTW I heard that Sheffield vs Nottingham medics is generic and not limited to neurology... I can't remember who mentioned it, I'm pretty certain it was off blog at a supper party, from a physicist who had worked for Nottingham Queens Medical in some capacity.

Total Perspective Vortex and vegicide

2010-07-22T18:30:00.006Z

For those who have failed to read the Hitchhiker's Guide to the Galaxy a little information about the Total Perspective Vortex is required. It's in context here.

The relevant quote is this one:

"To Trin Tragula’s horror, the shock completely annihilated her [his wife's] brain; but to his satisfaction he realized that he had proved conclusively that if life is going to exist in a Universe of this size, then the one thing it cannot have is a sense of proportion"

I hate to mention anyone with an annihilated brain after mentioning poor Dr Stanton, but here is the key quote from Dr T Colon Campbell (none of the rest is worth reading):

"In summary, Denise’s critique lacks a sense of proportionality."

Phew, just as well, we need Denise with a non annihilated brain to crunch numbers for us.

But the implication, unstated, is that Dr Colon has a sense of proportionality.

Explains a lot really.

Peter

BTW Zaphod eats the cake. There, ruined the series for you!

Where is the brain of Rosemary Stanton?

2010-07-20T20:36:00.009Z

I've posted on Dr Peter Clifton in the past. He's in the news again. Here's the link to the Telegraph article from Blogblog plus the text is also over on the trialblog archive for when the link goes down. Obviously there is a limit to the functionality of his brain implant (inability to perceive that obesity is a symptom not a disease for example, still pro vegetables because they are low in calories, no idea of the role of insulin in obesity etc) but he does seem to be able to conceive that five a day of fruit 'n' veg are a waste of money. That is utterly amazing.

Hmmmmm. On re reading the article, apart from finding fruit and veg useless, he still seems utterly lost as far as meaningful comprehension goes.

Still, Clifton's brain implant has some residual functionality. But where did the brain come from???? Could it have been stolen from Dr Rosemary Stanton? The Dr as in the last sentence in the Telegraph article:

"Nutritionist Dr Rosemary Stanton cast doubt on the findings and suggested the study [Clifton's] could be flawed."

Her brain could easily have been taken as the source of whatever residual central processing power is available to Dr Clifton. Replacing Dr Stanton's brain with a low IQ parrot would leave her fully functional as a nutritionist... It all fits together.

Peter

PPT and unreported side effects

2010-07-16T05:08:00.003Z

Gifted by Gary!

Peter