Saturday, May 01, 2021

Feeling experimental?

This is the observational study from Israel through their Pfizer vaccine roll out:

which has this excellent table showing some degree of vaccine efficacy:

Which, understandably, only starts at 14 days after first vaccination. No one would expect a vaccine to generate immunity sooner than 14 days. So we don't need to look at those initial 14 days. Interestingly, as well as excluding the first 14 days, they also excluded 26,000 care-home/housebound people and 25,000 health care workers, I've no idea why. I'd be really interested to see how the vaccine worked in elderly "crumbly" people and those who cared for them. But that's just me.

This next snippet is just a pre-print, and might stay that way. They simply reverse engineered one of the graphs in the above paper, did some basic calculations on the numbers at-risk vs infected and extracted the incidence of PCR positivity, "cases", in the earliest days of the vaccine roll out

and found, surprisingly, that people were more likely to test positive for SARS-CoV-2 in the two weeks after the vaccine compared to the non-vaccinated arm. The risk doubles. Like this:

There is a slightly sideways suggestion as to why this might occur:

"But there was a strong increase in incidence over the first week after the injection. If the increase in incidence during the first few days after immunization is a result of people being less careful after they have had their first injection, then the vaccine effectiveness after a single dose may be even greater."

ie people might have been rather less careful than they should been for the first week after the vaccine. Those Israelis are such party animals.

Now I've just picked up this peer reviewed study via twitter, again extracted from Israeli mass vaccination data:

Initial report of decreased SARS-CoV-2 viral load after inoculation with the BNT162b2 vaccine

looking at the viral load as assessed by PCR cycle threshold, from day 1 onwards after vaccination:

These people are looking at the PCR cycle threshold value for a positive test as a surrogate for viral load, ie how badly infected a person might be. Obviously, the lower the CT value the more virus is present. It just struck me that people presenting with a requirement for PCR testing 3 days after their vaccine had twice the viral load (CT drops from 25 to 24, ie a doubling of viral load) than at any other time point. This might be random chance, but may not be.

Next we can look at the elderly people in care homes in Denmark (again just a pre-print, but less controversial this time):

Incidence went up from 488 before vaccination to 760 in the first two weeks after vaccination, before improving progressively there-after. You can see in the right hand columns for vaccine efficacy that the two weeks after vaccination show a negative efficacy value.

but this time included the AZ vector vaccine too, this will be a generic effect.

Not so easy to make out in this study, everything is expressed in Odds Ratios, ie your risk of getting infected. Non-vaccinated individuals are considered at baseline risk, ie an OR 1.0 and are highlighted with a red circle. Just being "about to be vaccinated" people (blue circle) is massively protective. I know that sounds bizarre but the baseline and pre-vaccine people will be at differing times and infection rates vary greatly over time. A falling rate of population infection (due to Gompertz/seasonality, which control everything) is massively protective against infection. Being alive after the January peak is highly protective compared to living through the December rise.

Anyhoo, we next have days 0-7 post vaccine (green arrow), higher OR of testing positive soon after your vaccine. This worsens to the blue arrowed value for days 8-20 post vaccine before the vaccine finally kicks in as shown by the yellow arrow. I'm not going to criticise the vaccine but the yellow "arrow of success" looks pretty close to the blue circle of "about to be vaccinated". Fascinating.

This is one of the first assessments of the Pfizer vaccine from way back:

Safety and Immunogenicity of Two RNA-Based Covid-19 Vaccine Candidates

and this is supplementary figure S3 section a

The Pfizer vaccine is marketed at the 30microgram dose rate, that's the brown plots. Over days 1-3 the lymphocyte count drops precipitously. If I have a patient on chemo whose lymphocytes have dropped below 1.0 10^9/l I would be worrying about immunosuppression. The effect is gone by a week. They never checked if it happens after the second dose.


It has been pointed out to me that figure S3a is actually BNT162b1 and the vaccine actually selected for marketing was (sensibly) BNT162b2, which has a much milder effect on the lymphocyte count. So I have to consider that lymphopaenia might not be the mechanism or, if it is still the mechanism, it will only apply to those at the lower end of the box and whisker plots. The plots from BNT162b2 are here, first in 18-55 year olds:

and here for the over 55 year olds

showing a very minor effect. I still ponder whether this might have a significant effect but obviously that question is wide open. The increased infection rate is too generic to be fluke, the question is more how relevant lymphopaenia might be as an explanation.

End edit.

Lymphocytes come in many flavours. Some are irrelevant to dealing with acute infections, some are critical. On initial exposure to a virus it is the non-specific parts of the immune system which save your life in the first few days. Never mind B cells or T cells, they are critical for long term effects. In the acute phase, where the immune system has met an unknown pathogen, it's lymphocytes like natural killer cells that are going to save you. It is impossible to overstate the critical nature of the lymphocytes of the innate arm of the immune system.

To differentiate T cells from B cells from NK cells requires immunohistochemistry. This wasn't done because the lymphopaenia was considered to be transient and of no clinical significance. Bloody hell.

Lymphocytes aren't there at normal levels in the first few days after a mRNA vaccination.

To get ill you still need to meet the virus. You will still look just like a COVID-19 case, who was "probably incubating" at the time of vaccination, or went out partying under lockdown on the day you got your shot. You will still come up positive on PCR, probably with a high viral load showing as a positive result at a low cycle threshold. You might still die.

All because you were acutely immunosuppressed when you met the virus. By the vaccine. Only for a few days.

Just a little browse through Pubmed-land pulls up fresh herpes infection in people already on immunosuppressive drugs for arthritis (Israel again) after COVID-19 vaccination. Some nasty pictures in the paper

Herpes zoster following BNT162b2 mRNA Covid-19 vaccination in patients with autoimmune inflammatory rheumatic diseases: a case series

and also, browsing the FDA commentary on the early trials

Emergency Use Authorization (EUA) for an Unapproved Product Review Memorandum

I picked up this line:

"Suspected COVID-19 cases that occurred within 7 days after any vaccination were 409 in the vaccine group vs. 287 in the placebo group."

These are people who looked like they had COVID-19 soon after vaccination but did not. They were PCR tested (sometimes very repeatedly) at high PCRct and were always negative. Call them ILI, influenza like illnesses. An excess in the week after vaccination occurred. Supportive of an acute immunosuppression post vaccination. It's usually SARS-CoV-2 that gets you but any other bug can do the job too.

Does any of this matter?


Here in the UK we had a wave of COVID-19 sweep much of the country in the spring 0f 2020. It ended largely due to the end of the winter respiratory virus season and it failed to fully penetrate to the north of England. The virus went on vacation in the summer, as respiratory viruses do. There was a finishing off of the first wave in the autumn, mostly in the northwest then the northeast. Then it started to peter out through November.

Personally I was expecting a mild winter respiratory virus season because the gross mis-management of the situation in nursing homes earlier in the year meant that many of the people who would normally have been going to die of influenza over Christmas had already been killed in the first COVID wave and its autumn residuals. And there was minimal influenza.

This didn't happen. In early December there was a modest upswing in cases, of COVID-19 this year as it was the dominant virus at the time. Then in mid December all hell broke loose.

It didn't matter what the COVID incidence was doing at a given location; it could be stable, rising or falling, there was a surge. It was big and the shape of the surge was exactly the same in all areas. The data came and went on twitter and I never screen-shotted it. Someone recently put up a related graph of the percentage positive tests which is okay but doesn't show the spectacular shape and synchrony of the absolute numbers of positive PCR test results. Here's the picture I have, best I can find:

And here the red line marks the start of vaccination roll-out and the blue line marks the start of the surge:

Here's the graph stretched out a little to show the linear rise in positivity, in all areas, over less than a week:

I'd forgotten about these weird sudden implausible rises in infection. I'd assumed the government had changed something about the PCR protocol (which they did do in December, to catch the B117 variant which spectacularly failed to kill everyone in Kent). What rekindled my interest was India.

I think these graphs are from Ted Petrou on twitter

The rises are not as synchronous as they were in the UK last December but the shape of the curves at the right hand end of the graphs is remarkably familiar. India is huge. Vaccine roll out will not be as synchronous as it was on our tiny island off the coast of Europe. Whatever India was doing before their vaccine roll out, maybe they should have just stuck with that.

A bit of an addendum:

In the UK we largely know when people received their vaccine doses, after all they're going to be needed for vaccination passports for as long as Bojo feels like imposing them. Probably for ever.

I never, ever, expected to see what vaccination does to illness, hospitalisation and death over the first few weeks because I was pretty sure it would be appalling. It was.

So I'm utterly amazed to see this:

The study is looking at hospitalisations and deaths related to time since vaccination in a cohort being followed as part of the study. You have to be ill enough to be hospitalised to be in the study so this helpfully excludes those massive numbers of false positive PCR results being generated in December before the PCRct was finally dropped from over 40 to a more reasonable 30 (still too high). These people were ill, and they were ill with SARS-CoV-2. Genuine cases as opposed to "cases".

As the CO-CIN researchers state

"Given that the median incubation period is 5 days, the distribution indicates that most vaccinated hospitalised patients were infected around the time of vaccination, and the remainder after vaccination but before immunity had developed"

Also included is what happened to anyone's granny (A UK tier 2 category patient) if she picked up SARS-CoV-2 in the immediate aftermath of her vaccine. About 10% of these tier 2 patients didn't survive.

How could vaccination trigger infection? CO-CIN state the normal explanation:

"Elderly and vulnerable people who had been shielding, may have inadvertently been exposed and infected either through the end-to-end process of vaccination, or shortly after vaccination through behavioural changes where they wrongly assume they are immune"

Which translates as they got infected at their vaccination centre. Or these elderly people went to Israeli-style parties, during lockdown, starting on the day of their first vaccine dose. Wild things, those folks in nursing homes.

We had a winter resurgence of COVID-19. It became an epic disaster as a direct result of the immunosuppressive vaccine program being started while SARS-CoV-2 was the prevalent virus. People went through a vaccine centre where SARS-CoV-2 was persisting in aerosol form in the local environment.

No one seems to have considered that the vaccine might be directly immunosuppressive. For young fit healthy people this might not matter. In a nursing home it's a death sentence for many. They died.

Someone needs to tell the Indian government. And maybe the Japanese government too, before they cancel the Olympics.

I hope we're all enjoying being part of a global drug trial based on 40,000 fit healthy people observed for two months in mid summer. The UK government is, as in Israel, going to coerce any unwilling "volunteers" to make them take part in this on-going experiment. Thank goodness we have the Nuremberg Code, for what that is worth here.


PS, from Australia:

"Western Australia's latest cases stem from a hotel quarantine security guard in his 20s who has tested positive to COVID-19 and was potentially infectious in the community for four days.

State health authorities said the guard, who recently received his first dose of the Pfizer COVID-19 vaccine, worked on the same floor as two other positive cases from the United States and Indonesia."

No laughing. It's not funny.

Wednesday, April 21, 2021

Surwit diet and derivatives (5) People and mice

George Henderson put up this link in comments to the last Surwit post

Small Amounts of Dietary Medium-Chain Fatty Acids Protect Against Insulin Resistance During Caloric Excess in Humans

It's a beauty. Following a standardised three day over feeding regimen, roughly one and three quarter times normal calorie intake, 82% of total calories as fat, you develop insulin resistance. Well, you do if the fat is predominantly saturated fat.

No one should be surprised at this. Sustained deliberate massive overfeeding has nothing to do with developing obesity in real life. Saturated fat makes adipocytes unwilling to accept this excess dietary fat so it is deposited anywhere the body can put it. The normal response to eating nearly twice your normal calories in a day is to eat less next day. But not if you are in an overfeeding study. So the unwillingness to store calories continues and the body's attempt to resist this (insulin resistance) continues.

If you do the same but replace just 30g of the 450g of saturated fat with MCTs (about 5% of total energy) you don't develop insulin resistance.

This is considered to be a Good Thing.

Personally, I think it's not. If you add some MCT oil to your saturated fat it is very clear that there is no resistance to the excess calories being put neatly and tidily in to storage. In to adipocytes. Which will expand. Which we call obesity. As in the obesogenic Surwit rodent diet...

The prediction from the Protons/ROS hypothesis is that under the Surwit diet that insulin sensitivity should be "improved" in the early stages due to the MCT lipids. That might actually show best if rodents were fed the Surwit diet but restricted in calories so the late onset obesity related insulin resistance doesn't obscure the underlying pathology.

I wonder, that's not difficult and might have been done... Time to hunt.

This was the first hit:

Fat, carbohydrate, and calories in the development of diabetes and obesity in the C57BL/6J mouse

by the original Surwits. Sadly Mr and Mrs Surwit didn't specify which high fat diet they used in this study. They cite two refs, one used coconut oil 

Differential effects of fat and sucrose on the development of obesity and diabetes in C57BL/6J and A/J mice

and one used "1850" by Bio-Serve.

Diet-Induced Type II Diabetes in C57BL/6J Mice

Modern Bio-Serve F1850 is a lard based high fat diet, so we'll never quite know which diet we are talking about in the restricted feeding regimen. However the question is the same: Do "high fat" diets work by sensitising adipocytes to over respond to insulin? Be that linoleic acid from lard or medium chain fatty acids from coconut oil.

This should show if you feed the obesogenic diet but restrict calories. Which is exactly what the Surwits did.

The high fat/restricted calories mice were not fed to be weight matched with the low fat mice, merely to be calorie matched. Of course, despite "calories in" being matched, the pair-fed high fat diet mice gained more weight than the low fat mice. I'm guessing they were a) very hungry and b) hypometabolic.

Here are the weights:

Blood glucose and insulin were measured at the times marked by the arrows. Glucose looks like this:

which is pretty boring and appears to reflect the relative body weights. Insulin comes out like this:

If we stick the hungry fat mouse values through an HOMA IR calculator (which gives silly numbers but allows a comparison) we get an HOMA score of 13.9 while for the control mice we get 16.2. The high fat fed partially starved mice are more insulin sensitive than the control mice. Given access to more food this insulin sensitivity would undoubtedly make them become fatter. And the fatness would eventually render them insulin resistant per se.

TLDR: The mice which are on a high fat diet but underfed are fatter than controls (despite equal calories) but have LOWER insulin and lower insulin resistance than controls. Surwit diets make you insulin sensitive and this makes you fat.

With thanks to George and the Surwits.


Tuesday, April 20, 2021

Maintaining muscle function in to old age

An aside: Public Service announcement. I seem to have a lot of Faceache/book friend requests coming through at the moment. Once upon a time I accepted all friend request and have read some interesting posts as a result. But I don't use Faceache for anything technical. The occasional orchid picture or flat water paddling snap is about it. So now I don't accept friend requests unless I know the person. There's nothing Hyperlipid-ish in my FB posts and the algorisms bury the social stuff I'd like to see if I have too many friends. Sorry if it seems rude, it's not meant to be but there is no way round it. End of Public Service announcement.

Back to the post:

The start of the current gross stupidity of lockdown-2 seems to have vanished in to the haze of the past. I can't remember when I last went bouldering, pre-idiocity. I guess it was some time last December. In the dim and distant past of lockdown-1 the climbing wall was completely reset but during the current period of enforced sarcopaenia only small areas were changed, so I got the chance to see how well I fared on some familiar routes after months of enforced idleness.

Pretty well. Endurance was a bit down and finger strength was laughable but on routes with big chunky handholds going up the main competition wall my bulk muscle seems to cope remarkably well.

On which subject I was interested in this paper put up on Faceache by Jay Wortman

The ketogenic diet preserves skeletal muscle with aging in mice

which is strong in it bias-confirming ability, bearing in mind that the keto mice were not exactly spending hours a day in the gym. It's the same group that produced this study

which is also exactly what you want to hear if you are an old bloke like me with young kids.

But I never blogged about the original paper. It has a certain flaw, common to both papers, which made me slightly cautious. The paper is best described as one of those "think about it" studies. Here are the diets used for both:

and here are the survival curves

The first problem is that there is no mention of gas chromatography. We have no idea of what the PUFA content of the lard was and the lard makes up something over 80% of the calories of the ketogenic diet.

In a deeply ketogenic diet such as F3666 it doesn't matter what the PUFA content is and the lard content is relatively low anyway. But for a rodent diet supplying 10%of calories as protein and maybe 20-25% of calories as PUFA it might matter. It mattered in these papers:

"During this one month [ie the lead-in at 12 months of age] period, food intake was measured to determine the daily food intake required by these animals. At 12 months of age, mice were randomly placed on one of three diets: control, low-carbohydrate diet (LCD), or ketogenic diet (KD). The control diet contained (% of total kcal) 18% protein, 65% carbohydrate, and 17% fat. The LCD contained 20% protein, 10% carbohydrate, and 70% fat. The KD contained 10% protein, <1% carbohydrate, and 89% fat. For the longevity study, food intake was set at 11.9 kcal/day, and decreased to 11.2 kcal/day after weight gain was observed during the first weeks of the study."

The studies combined a ketogenic diet with calorie restriction. Calorie restriction is a known longevity promoter. Duh. And keto didn't maintain a normal weight.

Lard can contain anything from almost no PUFA up to more than 30% PUFA, depending on what the pig was fed on and how adulterated the lard has been with cheap vegetable oils.

So these ketogenic mice had to be on a calorie restricted diet because otherwise they gained weight. They were on a diet containing around 20%-ish of calories from linoleic acid. If they felt a hypo in the middle of the light period they would have eaten to correct the hypo. Pathological insulin sensitivity. Or just the loss of calories in to adipocytes without a hypo would generate simple hunger to off set those calories lost in to fat calls, ie weight gain.

Of course it's just a rodent study and maybe people would be different.

Or, more likely, maybe not.

As a more general point it's also worth noting that the improvement is in the median lifespan, not peak longevity. The first mouse to die was in the keto group, the last in the low carb group. Median does not mean an intervention is invariably perfect for all individuals.

But it's as good as we have at the moment.


Tuesday, April 13, 2021

The ginger paradox (6) Reward

Edit: The capitalisation of Reward is sarcasm. End edit.

Corn oil is very Rewarding for rodents. These people are working hard at the mechanism:

so let's not assume that Reward is some airy fairy concept, it's fully physiological. How Rewarding corn oil is in rodents is beautifully illustrated by the paper I  discussed recently in which mice, when given the choice, voluntarily consumed pure corn oil until it comprised roughly 84% of the total calories in their diet. Of pure fat.  Without training of any sort. This is the paper:

So of course the mice became obese. Okay, I'm making that bit up. Massive consumption of Rewarding corn oil does not make mice obese. They eat a little extra, admittedly, but that is because the metabolic effect of an 84% corn oil diet is to instigate uncoupling. A quirk of the biochemistry of linoleic acid, uncoupling proteins and rodent brown adipose tissue means that a certain amount of energy is wasted as heat, so the mice have to consume a little more corn oil to make up for this loss. A few extra total calories were consumed without any extra weight gain.

Metabolism + extra heat production = an extra amount of food has to be eaten to maintain normal weight.


Going on to look at mechanisms of Reward, this study 

found that the Reward of corn oil is neuronal, it comes from local metabolism of the oil on the tongue using a lingual lipase so that a tiny concentration of FFAs is sensed by receptors in the mouth and nerve signalling from here drives the dopamine release in the brain. You can bypass the lipase on the tongue by adding as little as 1% unesterified linoleic acid to mineral oil which mimics the approximate amount of FFAs provided as a stimulus from the more normal corn oil/lipase process.

To make it absolutely clear:

Mineral oil carrying 1% of free linoliec acid is as Rewarding as 100% neat corn oil because both provide roughly the same FFA drive to the sensory cells. You can measure the dopamine release in the rodent brain. It's the same because the sensory cells on the tongue see the same concentration of FFAs.

I have a thought experiment.

What if one group of mice/rats were given chow plus access to neat corn oil and another group of mice were given chow plus access to mineral oil with 1% free linoleic acid added?

The oils are equally Rewarding.

Would the mice consume the oils in equal amounts because both are equally Rewarding?

If the oils were consumed in equal amounts would the mineral oil mice lose weight?

Or would they eat extra chow?

My bet is that if you ran such a study for eight weeks the mice with access to the mineral oil wouldn't touch it with a barge pole. It might release dopamine in the nucleus accumbens but it's not going to do much to fuel metabolism. That would need chow. Maybe there might be some recreational flavoured mineral oil consumption but I think that would pale quite rapidly.

Oooooooh! They might develop Reward Resistance! Like leptin resistance but dumber.

Reward is the refuge of researchers who consider obesity is caused by eating in excess of your metabolic needs.

A more sensible view of obesity is that it results from a metabolically mediated loss of calories in to adipocytes which then requires more calories to be eaten to meet normal metabolic needs. In the same way as orlistat requires over eating to compensate for fat loss via faeces, so "fake" corn oil (1% linoleic acid in mineral oil) would require extra chow to make up for the lack of calories in that highly Rewarding fake oil. And why feeding D12492 means rodents have to consume extra D12492 because they lose calories in their adipocytes.

Just to summarise: high Reward food makes you fat only if its metabolism result in energy sequestration in to adipocytes. 

Real corn oil at 84% of calories is not obesogenic because it does't sequester calories in to fat cells. I don't care how Rewarding it is. Nor does metabolism care.


Surwit diet and derivatives (4)

I've been interested in the Surwit diet for years. It's a fascinating diet, high in saturated fat, low in PUFA yet undoubtedly obesogenic.

It's an interesting paradox to think about. As occasionally happens I found a non related paper which gives some suggestion of the mechanism. Here it is:

Characterizing the effects of saturated fatty acids on insulin signaling and ceramide and diacylglycerol accumulation in 3T3-L1 adipocytes and C2C12 myotubes

The paper uses adipocyte-like 3T3-L1 cells or muscle-like C2C12 myotubes. The 3T3-L1 cells might be worth another post in future, today is about the myotubes.

They looked at many things, but most interesting are the data on the ability of insulin to promote the storage of glucose in glycogen granules. I, being me, would look at this as a surrogate for un-measured lipid storage as lipid droplets in muscle cells. One of the cardinal rules of ectopic lipid deposition research is to never, ever suggest that myocyte lipid droplets might be enlarged by insulin signalling. They will be. Just like glycogen granules are enlarged by insulin.

So, practicalities. The myotubes were prepared in "low glucose" DMEM which is probably code for 5mmol/l, ie a normal physiological glucose concentration. To this medium was added a fatty acid at 0.75mmol/l, ie moderate fasting levels. Cells were incubated for 16 hours and then treated with supra-maximal insulin.

They noted that elevated pure palmitate is utterly harmless to cells in culture with normal glucose levels:

"Under these conditions, no signs of cell death were observed"

which certainly is not the case using 25mmol/l of glucose!

Here are the gels they obtained:

The top row, highlighted in red, is demonstrating the presence of phosphorylated (activated) Akt, a core insulin signalling step. We are comparing P-Akt under insulin and 5mmol/l glucose with that under insulin and 5mmol/l glucose plus 0.75mmol/l palmitate. It's clear that insulin signalling is markedly blunted by palmitate. If we look at the dashed oval we can see that the P-Akt band under oleate is comparable to that of the control.

The same applies to the level of phosphorylated glycogen synthase kinase 3 beta, a key enzyme in activating glycogen formation and outlined in blue. P-MAPK is irrelevant today but, again, might be interesting in the future.

Convincingly, palmitate causes insulin resistance and oleate doesn't. Bear in mind that this is a highly constrained experiment to make a specific point. These is no mention of ROS generation but it is worth looking at this from the Protons/ROS viewpoint.

Palmitate has an FADH2:NADH ratio of 0.484

Oleate has an F:N ratio of 0.457

In this experiment conditions are carefully controlled to give us an all or nothing response, almost like switch. The switch trips somewhere between an F:N of 0.484 and 0.457. Insulin resistant vs insulin sensitive. No double bonds vs one double bond.

It is possible to adjust the F:N ratio by smaller amounts than by adding a double bond simply by altering the length of a saturated fat. If we consider myristic acid the F:N ratio is 0.482 and for lauric acid it is 0.478.

The paper went on to look at insulin signalling using these fats and here are the gels they obtained:

At the extreme left is the control without insulin, next is control with supra-maximal insulin but no fatty acid, then rest of the bands have the indicated fatty acids added, all at 0.75mmol/l. I've put in the red line to divide insulin sensitive from insulin resistant results. Everything to the left of the line causes no insulin resistance, to the right significant insulin resistance. The switch is between myritic acid and palmitic acid, F:N 0.482 and 0.484.

I would expect C10 capric acid to be insulin signal facilitating and probably C8 caprylic acid too, although its strongly ketogenic effect and partial conversion to palmitate might make that less predictable.

Coconut oil is primarily medium chain triglycerides with F:N ratios on the insulin sensitising side of the switch. Formulating a high fat diet out of insulin sensitising fats combined with an insulogenic carbohydrate load seems like a good recipe for obesity.

It's always worth reiterating that there is no "switch" as such, there is a general integration of information about energy status and demand using ROS which can be pushed towards lipid storage or use depending on particular inputs. The F:N ratio looks like a switch in a very simple model asking a very simple yes-no question. But that's still useful information for understanding the Surwit diet.


Saturday, April 10, 2021

The complete and unifying explanation of human evolution

Miki Ben-dor has a new post on his blog

The complete and unifying explanation of human evolution

If you've not read his blog before, now would be a good time to start.


The ginger paradox (5) and some speculation

TLDR: If resisting insulin is rendered impossible due to very, very high PUFA diets then mitochondria resort to uncoupling.

reiterated the well known essentiality of FFAs for the activation of UCP-1 and added in the significant role of reactive alkenyl species. In more common parlance that would be lipid peroxides, primarily those derived from linoleic acid. I thought about it in this post.

This is the next step, which I specifically went looking for because this is how I think life should be organised. It is a perfect example of me having a huge bias, knowing what I want, and going looking for it. You have been warned.

It is utterly clear that UCPs in general suppress ROS generation and that some members of the family are not being used for thermogenesis at all, more likely for prevention of the generation of supra-physiological levels of ROS.

We have an interesting situation where PUFAs, the prime pathology of which is their failure to generate adequate ROS, are also extremely effective at facilitating uncoupling, which needs significant ROS generation to happen. Where does this superoxide come from?

This is the core question.  

Warning: I think step f) is the one I have least evidence for. Life is like that sometimes.

Okay. The story so far:

Caloric ingress in to a cell is controlled to an appropriate level while calories are freely available by limiting insulin signalling.

Insulin signalling is curtailed by driving electrons in reverse through complex I to generate superoxide and hydrogen peroxide which disable/limit said insulin signalling.

This reverse electron transport rises in direct proportion of FADH2 supplied compared to the amount of NADH.

The presence of double bonds in fatty acids limits FADH2 generation, limited FADH2 generation limits the control of insulin facilitated caloric ingress and continued insulin signalling diverts calories in to storage.

I have to accept that not all excess calories will be stored, some will continue to enter the electron transport chain as both NADH and FADH2. If electrons enter the electron transport chain when there is a low (relative) demand for ATP then

a) mitochondria membrane potential will rise, a direct consequence of the inability to limit electrons entering the ETC through complex I and multiple FADH2 entrance points. Protons are pumped but not used

b) the cytochrome C pool will become progressively more reduced, limiting it's ability to accept electrons from complex III

c) electrons will be transported through the cytochrome b centre of complex III back on to the CoQ couple

d) these electrons will replace those absent as a result of double bond containing fatty acid oxidation and will restore superoxide production

e) superoxide production, under these circumstances, is being facilitated only at the cost of high membrane potential secondary to low ATP synthase activity in parallel to excess calorie storage

f) if the double bond content of the lipids providing input to the CoQ couple from beta oxidation is very, very high then the need for negative feedback through complex III will be very, very high as well and will be associated with an excessively high membrane potential

g) the answer to excess membrane potential is uncoupling

h) superoxide positively regulates the activity of UCP-1 as do superoxide derivatives of LA

i) uncoupling allows the flow of electrons down the electron transport chain and lowers membrane potential, it immediately stops reverse electron transport/superoxide generation and converts the excess calories entering the cell in to heat, water and carbon dioxide


Normally regulated calorie ingress to a cell occurs when linoleic acid is low.

Excess ingress from LA is dealt with by diversion to storage, leading to obesity.

Marked excess is dealt with by uncoupling which does not "require" obesity.

There are no hard boundaries between the above conditions, there simply appears to be an inverse "U" shaped curve in response to the content of linoleic acid in the diet. Such curves are common in nature.

A few last thoughts:

Simply looking at the experimental data the situation appears to be that including linoleic acid at levels between somewhere just under 10% up to somewhere in the high 20%s will facilitate excess insulin action and excess lipid storage. As we increase the supply of linoleic acid through the 30%s and in to the 40% region of calories then uncoupling becomes the primary molecular solution to a progressively more intractable problem.

It is worth pointing out that in a given mitochondrion there are lots of CoQ/CoQH2 molecules, lots of beta oxidation sites and, while the calculation of FADH2:NADH is useful for insight as to how RET works for a single fatty acid molecule, the mitochondria are integrating lots of FADH2 production sources, lots of NADH sources and are continuously monitoring the membrane potential (which is an integration of energy input/need) as well as the redox state of the CoQ couple.

What happens on a whole organism basis is also an integration of all of these effects. The mechanism for weight loss in high PUFA diets is both comprehensible and plausible.

The studies are real, the data are real.

Personally I still wouldn't go there, but understanding them is key. 


Friday, April 09, 2021

The ginger paradox (4)

Here we go with ad-lib corn oil.

Voluntary corn oil ingestion increases energy expenditure and interscapular UCP1 expression through the sympathetic nerve in C57BL/6 mice

Mice were either offered chow from a hopper or chow from a hopper with the option of corn oil from a drinker bottle in addition. They like corn oil.

The mice with access to corn oil ate more calories than those without:

but most calories weren't from chow, top line is grams of chow only, bottom line the weight of chow eaten when there is access to ad lib corn oil:

We can look at the total amount of corn oil consumed:

Assuming 9kcal/g we can now reverse engineer that to 16kcal of corn oil a day as part of a total daily intake of 19kcal. So that's 84% of calories from corn oil. As 55% of this 84% is linoleic acid that gives 46% of calories as LA. Well in to the weight loss range of intake noted for high LA safflower oil, in fact that's verging on a self selected ketogenic diet, which complicates matters a little.  With 16% of calories from chow this will also be rather low in protein, though far from zero carb. Just look at the RER if they have access to corn oil, the black circles. Yes, these mice really are oxidising lipid and very little else, but also bear in mind that exactly the same effect could be obtained with safflower oil under far from ketogenic/low protein conditions. Here are the RERs:

Anyhoo. What was the end result? These are the body weights at the end of the eight week trial:

More calories, more oxygen consumption, same body weight.

This looks like a generic property of linoleic acid in exactly the same way as weight gain is at lower levels. The Jacobs study rats were around 24%, on the border between obesogenic and weight limiting effects, on the obesity side.

To get weight loss you need to go higher with the LA.

Just before I finish and post some speculation about mechanisms it's clear from the rest of this study that uncoupling is the answer to the paradox. In modern mice this is mediated through UCP-1 within the interscapular brown adipose tissue, as the paper went to considerable lengths to demonstrate.

This is the current level of development in the modern evolutionary terms of rodents. It's a sophisticaled high level system which will overlay the insulin system which will overlay the ROS system. It is perfectly possible to make a case for why this high level system is advantageous by thinking about the underlying ROS system.

I'll have a discuss about that in the next post.

This series is looking at body weight. Using an approach to normalise body weight which involves the incorporation of markedly unsaturated lipids in to the inner mitochondrial membrane does not strike me as a sensible thing to do. Might be a technique for looking good in your coffin.


The ginger paradox (3)

Here is the next step. Mice this time.

Prevention of diet-induced obesity by safflower oil: insights at the levels of PPARa, Orexin, and Ghrelin gene expression of adipocytes in mice

The basic study design was that mice were fed a control diet, a safflower oil based diet or a lard based diet for an initial 10 weeks. At 10 weeks half of the lard fed mice were switched to the safflower oil based diet and feeding continued for another 10 weeks.

Here are the diets

They measured the linoleic acid content by gas chromatography. That is very, very good. We can rough out the LA content of the control diet at around 5% of calories as LA, the lard diet at 11% of calories as LA and the high safflower oil diet at around 38% LA.

Here's what happened to the weights

As expected the lard mice became overweight by 10 weeks. Putting them on to 38% of calories as LA returned their weight to that of control mice or that of mice fed 38% LA safflower throughout the full 20 weeks.

This is not an isolated study showing the benefits of safflower oil, but it's one of the better ones. I find it impressive. It has to be understood.

Towards the end of the discussion in this paper the authors cite another gem which completely contradicts their own findings while providing more insight:

"These results are different to the study that the rats fed on 30% safflower oil and mice fed with 20% safflower oil showed significantly higher body weight, white adipose tissue weight, serum leptin, and hepatic PPARa mRNA expression [28]."

The paper they cite is this one:

Changes in liver PPARa mRNA expression in response to two levels of high-safflower-oil diets correlate with changes in adiposity and serum leptin in rats and mice

Here are the diets

Wow! Have you spotted it? Thats right. More excellent gas chromatography and suddenly you find out that "safflower oil" and "safflower oil" can be very, very different oils. This batch of safflower oil was 24.1% LA. In the highest fat diet we are looking at 24.1% of the 53.68% of fat calories as LA. That's 13% of calories as LA, bang in the middle of the obesogenic range. That's very different from the 38% which corrects obesity...

It must be sad trying to understand your own results and those of rival labs without the Protons/ROS hypothesis to fall back on. Must be awful.

Currently I don't think there is anything special about safflower oil. I think it is an effect the linoleic acid at very high dose rates. You should, theoretically, be able to do the same with corn oil. Sadly most of the corn oil based high fat diets aim to get in to the sweet spot of 10-20% of calories as LA. They want obesity after all.

If we are trying to generate diets with 40% or more of total calories from linoleic acid it will be much easier with safflower oil at 75% LA than using corn oil at 55% LA.

Interestingly mice appear to rather like corn oil. Let's look at a free choice feeding study next. Chow as pellets or corn oil from a liquid feeder bottle. Let the mice decide how much of each... And see if they get fat.


Thursday, April 08, 2021

The ginger paradox (2)

Here is ref 17 from the previous post

Effect of short-term dietary fat on cell growth in rat gastrointestinal mucosa and pancreas

Here are the diets by weight of ingredients

and here are the relevant weights after four weeks on the diets

I think it's unarguable that the weight gains are only trivially different between the three groups. It becomes clearer when you look at lard in terms of linoleic acid level as opposed to accepting that it is "saturated fat". Modern lard is around 12% linoleic acid. It might have been a little higher or lower in the 1980s depending on how much adulteration with cheap seed oils the manufacture could get away with in those days or what the pigs were fed on 40 years ago. Lets go with 12% to include the splash of corn oil thrown in.

The control diet is reported as 16.8% total calories as fat and both high fat diets as 52% of calories from fat.

That makes the control diet around 9% linoleic acid, the lard diet 12% linoleic acid and the corn oil diet around 28%.

At 9% LA the control diet is already obesogenic. The lard diet is a bit worse but not in a different ball park, much as I would expect. The fascinating one is the lack of excess weight in the corn oil group, the group with the diet used by the Cairo study as their obesogenic one.

The easy part is to assume that all of the diets in the Jacobs paper are obesogeic, as is the corn oil diet used in the Cairo study. All of these rats gained about 150-180g. The control diet in Cairo was unspecified chow. If it contained 4% or less of linoleic acid we have a plausible explanation for the low weight gain in that control group. We just have to explain why the rats in Jacobs' paper on 12% LA weighed about the same as those on 28% LA.

This is very important to me. There are a series of papers using very high LA diets, especially Safflower oil based, which show minimal obesogenic effects and even the ability to partially reverse lard derived obesity. Something I have been thinking about for years.


The ginger paradox

For odd reasons I was looking for papers on orlistat, in particular for rodent papers about the drug which might demonstrate effects relevant to the Protons/ROS hypothesis.

Rodent reports seem to divide up in to those which use an intermittent oral dosing regime vs those which incorporate the drug in to food as a fixed component of the ration. It became clear that if you mix orlistat with the ration you can exactly titrate the amount of lipase inhibitor to the dose of fat administered and include this with every meal and every snack, whatever the size and whenever consumed. This latter has no bearing on the real life use of the drug where it is given three times daily to establish a background inhibition of enteric lipases and people have to judge their fat intake in relation to how far they are from the nearest toilet and if they are carrying spare underwear. Not the most successful or pleasant drug for weight loss per unit grief and it doesn't seem to work very well.

Of course unpredictable bowel function doesn't matter to a lab rat, it's not wearing underwear and it can pooh whenever it likes, wherever it likes because it lives in a mesh floored cage.

There is remarkably little in the rodent literature on orlistat alone for obesity control and mostly you have to look at drug or supplement trials where orlistat was used as the control/usual care group. In these trials it is usual to use intermittent oral dosing rather than admixture to the food because intermittent oral dosing doesn't work very well. If you have an ineffective but conventionally accepted drug that then provides an ideal comparator to show your intervention does something good.

Aside: Just think of metaclopramide. It was/is a standard antinausea/antiemetic for post op use. It is ineffective, dreadful stuff but it's licensed. Which makes it ideal as a "standard therapy" against which to compare a lovely modern drug such as maropitant or ondansetron. You know the latter are going to beat metaclopramide  hands down because metaclopramide is little better than placebo and makes you feel crap. Study design is important and this shows in the methods section. End aside.

However some trials do use the effective food admixture method. I found an innocent little study from 2013 which did just this:

Comparative evaluation of the efficacy of ginger and orlistat on obesity management, pancreatic lipase and liver peroxisomal catalase enzyme in male albino rats

It feels like a throwback to the 1950s. They generated their intervention (ground ginger, 5% by weight of the diet) by going to the local market in Cairo and buying some ginger, peeling it, washing it, mincing it and air drying it before milling it in to a fine flour to incorporate in to the diet. The comparator intervention was orlistat which they bought as capsules to be opened and incorporated in to the ration in a similar manner to the ginger.

The bottom line is that their ginger worked rather well compared to an unmodified high fat diet but sadly (for the ginger) the orlistat was incredibly effective, far more so than the ginger. This is why I got interested in the study. Not only did the rats on orlistat fail to grow, they had a marked increase in food intake. They ate a ton of high fat food yet put on remarkably little weight. There is no information provided about bowel function but I guess the rats on orlistat didn't wear underwear and they lived their lives metaphorically sitting on the loo. Certainly whenever they ate anything. Which was as often as possible.

The basic premise to orlistat is that if you take a drug which blocks fat absorption you decrease the functional "calories-in" so lose weight. Which is, of course, bollocks. What would actually happen is that you would eat more. You cannot fool your metabolism. You either eat more to meet your needs or you slow your metabolism to match your available calories. You feel cold, move as little as possible and dream about food. Most people would eat more.

This is what happened

Chow rats gained 60g, high fat fed rats gained 130g, orlistat treated high fat fed rats gained 7g. Seven grams. These rats did not want to be slim. They are not heading for the beach in a bikini. That low weight gain is malabsorption in action.

It causes hyperphagia because that is the only way the rats can even try to meet their caloric needs.

The implication of this study is that malabsorption makes you thin. That could be CICO. But orlistat malabsorption might also block linoleic acid absorption. That this might actually be true in real live people to facilitate a little genuine fat loss is where I was heading, but I lost interest when I tracked back through ref 17 to find that the high fat diet cited in this study is not obesogenic! Ref 17 as mentioned in:

"Group (2) G2: (High fat diet), rats of this group fed high fat diet (The diet contain 30% corn oil) according to Jacobs17"

A diet composed of 30% corn oil by weight, around 26% of calories from linoleic acid, is not obesogenic, in rats under the supervision of Jacobs.

Yet it clearly is obesogenic in Cairo.

Now that is interesting. These are thing which fascinate me. Ref 17 is next.


Monday, April 05, 2021

Butter vs peanut butter

It was specifically designed to show that fat raised insulin and that saturated fat was particularly bad in this role.

It produced this graph:

Let's imagine the group leader has sketched out in advance the above graph or something like it which he wants the PhD student to aim for as their results.

Group Leader: How are you going to generate these graphs?

PhD student: Well, seems like a pot of yogurt, a slice of bread, some plain pasta and a dose of each type of fat might work...

Sadly life is not quite that simple. The insulinogenic components would need to be chosen to produce a small but measurable insulin response. Not so small as to be undetectable but not so large as to tax the pancreas or overwhelm the effect sought. Then there had to be enough fat to augment insulin secretion and generate the appropriate resistance to that signal, within the normal physiological range of pancreatic function. So the amount of fat would have to be very carefully adjusted to give an ideal amplification of the carbohydrate/protein insulin signal. In the end it turned out to be necessary to adjust the quantities of food directly to the body surface area of the participants, not a fixed meal and not even calories merely adjusted to bodyweight. The use of body surface area is normal for calculating doses for various highly toxic treatments such as chemotherapy because dosing has to be as precise as possible in this instance. Turns out this dose/surface area was needed to correctly dose the fat (50g/m2) and pasta (30g/m2) to illustrate the double bond/ROS effect. The yogurt and plain bread got a free pass.

But they did all of this successfully, got the "down" on saturated fat and polished the halo of olive oil. 

I'm both impressed and grateful.

Now let's go back in time to the 1980s and look at this study:

The agenda in this study is to show that fat blunts insulin response to carbohydrate ingestion but causes delayed insulin resistance during the following meal. They threw in a butter group and a peanut butter group. Here are their results, I've chopped off the right hand end about the follow on meal as it's not relevant here:

We can also ignore the 2 X WB line which was just 480kcal of bread with a smear of cottage cheese. The lower two lines are bread alone  vs the same dose of bread with some fat. Both fat sources produced results which were indistinguishable so were combined. The insulin response is exactly the same with or without fat, saturated or unsaturated.. 

How do you reconcile the two studies?

This second one used a fixed calorie meal with 50g of carbohydrate and 25g of protein. Fat provided around 25g for each meal.

The dose of insulinogenic substrate was well over half of the calories in the meal, the fat well under half. The total gross insulin response was to the bread, not the fat. The amount of fat was insufficient to make any detectable difference to that insulin response.

Just compare the insulin values achieved in each study, the Spanish study use a fat-free insulinogenic stimulus raising insulin from 50pmol/l up to about 70pmol/l. The bread meal raised insulin from around 70pmol/l (10mU/l) to around 400pmol/l (60mU/l), even without any added fat! There is no scope for picking up any effect of the fat, let alone from the nature of the fat. The bread effect was approaching maximal, even though it didn't quite max out the pancreas as much as the double bread meal did.

Ultimately you design your study around the result you want to generate. Sometimes it's easier than others.

The Spanish study was remarkably cleverly done but looks like they had to work hard to get the results they wanted. I still like it, even though I markedly disagree with their interpretation of the findings.


Saturday, April 03, 2021

Israel is doing really well for COVID-19 vaccination

Israel has missed out on submitting data to EUROMOMO for week 13 of this year. During week 12 they recorded a marked, unique, increase in all cause mortality in their over 65 year olds, almost all of whom are now fully vaccinated against COVID-19 with the Pfizer vaccine.

These people do not appear to have died of COVID. It seems to be mostly cardiac problems which don't seem to be particularly well defined. Translated from a Hebrew newspaper via Google as a specialist saying "We are now witnessing a murky wave of heart attacks."

The now-outdated week 12 data are presented on-line by a group called Swiss Policy Research. I have no idea of their affiliations, politics or agenda and, frankly, I don't care. The graph certainly looks like a EUROMOMO graph and Israel has not, as of today, submitted their week 13 data.

Of course these data are provisional and, of course, numbers of deaths in week 13 might be really low but the Israelis just haven't gotten around to submitting the numbers yet. Maybe they're too busy partying in celebration of their vaccine success. EDIT Or Passover! END EDIT

I'm uncomfortable about ADE with these vaccines. I'm concerned about triggering auto-immune diseases. I've not really considered the thrombogenic/disseminated intravascular coagulation potential but it's also there to worry about.

The European Medicines Agency is responsible for the authorisation of SARS-CoV-2 vaccines in Europe.

Doctors For COVID Ethics are currently in discussion with the head of the EMA with a view to starting a prosecution of EMA for crimes against humanity relating to these vaccines. The physiology and immunology which they cite as being relevant (and as yet un-assessed by the EMA) make a very interesting case.

I personally am very, very cautious about yielding to the coercive pressure to accept such a vaccine here. Coercion is becoming a part of reality in the UK. These vaccines are absolutely experimental in their technology, have never before been licensed anywhere in the world and will provide no benefit for the vast majority of the recipients. The sooner the legal cases actually begin the better. Sadly a victory in Europe would not get we folks in the UK out from under the Boris Johnson jackboot.

As always: If you are at risk of dying from COVID-19, take the vaccine. If you are not, think hard about it.


Tuesday, March 09, 2021

More musing about vaccines

We vets vaccinate dogs against infectious canine hepatitis. Many, many years ago we used a live vaccine derived from the adeno-1 virus, unless the animal was a sight hound, Salukis or Borzois being particular concerns. For these we had a less effective/convenient inactivated vaccine (not sure which adenovirus strain this came from) because sight hounds (no pun) were particularly prone to blindness with the live attenuated A-1 vaccine. As the manufacturers of the A-1 vaccine stated, from memory, it "may cause corneal oedema which is usually transient".

If you translate that in to real terms it comes out as "can cause blindness which can be permanent".

Woe betide you if your boss found you had inadvertently picked up the wrong vaccine vial for a sight hound. Obviously, not all sight hounds went blind after the A-1 live vaccine.

The whole problem disappeared with the advent of the A-2 live vaccine (which we love), free from the corneal side effect, so I doubt kiddie vets are even aware that blindness was a predictable problem following a routine vaccination if you (and your patient) were unlucky. The modern A-2 vaccine is so effective I doubt we ever see infectious canine hepatitis nowadays but I recall seeing transient corneal oedema in at least one clinical viral hepatitis case in my early days.

I am one of those selfish people who is intending to defer my SARS-CoV-2 vaccination. The Queen does not approve. 

Why should I be so selfish? Many reasons, but the main one is an uncomfortable feeling about how m-RNA vaccines work. As I understand it, you inject a section of m-RNA enclosed in a vesicle which is muscle absorbed. The m-RNA is used by normal ribosomes to generate viral spike protein which is presented to the immune system on the surface of the muscle cells affected. The immune system sees the protein and responds as to the virus. You become immune. The residual m-RNA is fairly rapidly degraded and disappears until you get your next dose. I stand to be corrected if I am misunderstanding this.

I have no idea whether muscles infected with the field virus express spike protein on their surface. I suppose they might. Or they might not.

Does anyone think that expressing a viral spike protein on muscle cells will only generate an immune response to only that spike protein? Or, in the immune melee which results from muscle expressing an highly immunogenic foreign protein, would an immune response to other components of muscle surface occur?

How might you recognise such a response?

Myalgia perhaps?

Would it be better or worse the second time you played this game?

What would happen if you had already recovered from the field virus and so were very primed to effectively attack anything looking remotely like a SARS-CoV-2 virus surface protein?

So many questions.

Myalgia is common after vaccination, worse after the second dose and worse still if given to someone who has previously recovered from the field virus infection.

Heart muscle is not skeletal muscle. It probably "looks" different to the immune system. But it's not completely different. I, personally and just for myself, am not comfortable with making antibodies which might precipitate an attack on my myocardium. Which might not occur. Or, if it did, might be temporary. Or not. I remember the live A-1 adenovirus vaccine. This is just one of the problems of being as old as I am but still remembering my clinical experiences from the early 1980s.

So. Does myocarditis occur in the aftermath of SARS-CoV-2 m-RNA vaccination? Of course not. Do you have any concept of how much money is involved in these vaccines?

This is just from twitter so can be ignored if you wish:

I have no ideal who the tweeter is and I don't read Hebrew, so I have no way of following this up.

But I note that the Queen's recently vaccinated hubby has been passed around from hospital to hospital and has gravitated to being managed by cardiologists for his mystery illness. He's very elderly so this is probably just random chance and nothing to do with any vaccine.

The first Swine Flu pandemic vaccination program was halted in 1976 due to worries about Guillain-Barré syndrome from the vaccine. The same happened in the second Swine Flu pandemic of 2009-10 when narcolepsy halted that vaccination program.

The m-RNA vaccine will obviously be problem free.

I'm so selfish.


BTW, each person should assess their own risk from the virus vs their concern re the vaccine. Personally I consider my risk from the virus is very low so am un-enthused at any risk from the vaccine. Certainly for the next couple of years. It remains to be seen how much coercive pressure is going to be applied nation-wide and especially to myself to get vaccinated. I've ignored six invitations so far.

Sunday, March 07, 2021

A chat with David Gornoski

Okay. Head briefly above water for a few minutes!

I had a chat with David Gornoski last week (or rather it was the week before, things are a little hectic here). You can find it at

and on Youtube here

David had emailed me after a number of people he'd already interviewed had mentioned the Protons/ROS hypothesis and Hyperlipid, so mostly I was trying to to get across the where the key concepts came from. I guess I rabbited on a lot about about the four main papers which shaped the idea. Then we wandered away on to more general things.

I think the microphone works!


Sunday, February 07, 2021

Just an announcement

The World Nutrition Summit is coming soon as a virtual meeting based in South Africa. The organisers kindly asked for a presentation based around the ROS hypothesis of obesity. I haven’t tried to make it particularly user friendly, Mike Eades has already done that, this is more of a brief whirlwind tour of the many technical papers which went to make up the Protons thread and spawned the idea.

Thee's a lot more information from the Nutrition Foundation here.

I bought a microphone.


Sunday, January 31, 2021

Hall and CICO part 3

Okay, this is the image I missed on my first read through the results/methods of Hall's latest offering:

I have to apologise for failing to pick this up possibly because I would never read the discussion or conclusion of a Hall paper. My interest in what Hall thinks is distinctly limited. The image shows a delay in the onset of fat mass loss with LC which then proceeds at a remarkably similar rate to the fat loss in the LF group.

But clearly, the changes in fat mass under LC trend upwards (ns) initially before trending downwards, (also ns) compared to fat mass at initiation of the diet.

As David Ludwig has pointed out, appetite suppression on LC can be delayed and shows most reliably from 2 weeks onwards. This might well be related to the rising levels of ketone bodies providing enhanced energy availability as ketosis develops using the concept outlined here:

This brings to mind a very short term study from some time ago looking at ketogenic diets based around saturated vs polyunsaturated fats.

Differential Metabolic Effects of Saturated Versus Polyunsaturated Fats in Ketogenic Diets

Both diets were individualised to be weight maintaining, so we can say nothing about spontaneous food intake (ie appetite, ie weight/fat mass changes). The main point of interest is the very right hand end of Figure 1:

which shows calculated insulin sensitivity. Under high PUFA intake insulin sensitivity, after an overnight fast, is clearly enhanced.

We have no information about the FFA levels so assessing the "blood energy content" is impossible for either diet. However we can look at the relative changes in glucose vs beta hydroxybutyrate (BHB). They look to be reciprocal, but this is simply an artefact of percentage change.

Glucose drops by 10% from normal fasting levels in the PUFA group, measured as 79.2mg/dl, a sizeable number. Ketones in the PUFA group rise by 10% over the same period. But this is 10% of 1.34mg/dl, a vanishingly small amount, physiologically. There is no ability for this modest rise in BHB to offset the fall in glucose. The energy content of ketone bodies and glucose are approximately equal, per gram. Free fatty acids would be the unknown confounder.

That study looked at high (10% energy) vs very high (42% energy) from PUFA intakes, both under modest ketogenic conditions.

Hall's study looked at a mildly ketogenic diet with around 15% of energy from linoleic acid, a pathologically high intake, in comparison to a carbohydrate based diet deriving around 3% of calories from linoleic acid, ie a physiological linoleic acid intake. 

Linoleic acid at 3% of calories, ie very low, will have no blunting effect on the ability to limit caloric ingress in to adipocytes ("loss") in the peak-absorptive period (so will not generate the need to eat more food to offset this loss in to adipocytes) and will not facilitate pathological insulin sensitivity to allow hypoglycaemia in the post-absorptive period (with subsequent hunger).

I think we can sum Hall's study up in the words of the abstract section:

"One participant withdrew due to hypoglycemia during the low-carbohydrate diet."

translated as

"One participant withdrew due to hypoglycemia during the high-polyunsaturated fatty acid diet."

The other participants had to (spontaneously) eat more to successfully avoid these problems during the first week. 

The effect diminished through the second week of the study as ketones rose further to compensate for the hypoglycaemic effect of excess PUFA.