Endurance and oxygen flux during fatty acid oxidation

I was browsing Pubmed looking for other things when I came across this ancient publication by Stephen Phinney, from back in 1980. Those were the days. That was the Summer I contracted mycoplasmal arthritis as a final year vet student seeing practice in North Devon. Lots of NSAIDs then six weeks on tetracyclines once the serology came back positive. Yum. Anyway:

Capacity for Moderate Exercise in Obese Subjects after Adaptation to a Hypocaloric, Ketogenic Diet

Free full text, nice read. Replicable, if you have the equipment.

This is table II. For the first endurance test the treadmill was set at 3 mph with a personalised incline. The same test was then repeated after one and six weeks of a protein supplemented fast. For the six week treadmill run the settings were identical to the first sessions but the subjects wore backpacks containing weights equivalent to the bodyweight that they had lost during the 6 weeks of their fast. There was no exercise training in the interim.

The column to look at is the one in the middle labelled VO2 and expressed as ml/min. On a mixed diet the treadmill settings required a flux of oxygen of 1875ml/min to maintain this significant effort. After 6 weeks on a protein supplemented fast, wearing weights in a backpack to offset the bodyweight loss, with the same treadmill settings, subjects required 1497 ml/min of oxygen. That's a big drop.

Some of this is from the magic of ketones, BHB increasing the free energy of hydrolysis of ATP. A large chunk of this component should have been in place by the one week treadmill test as everyone was well in to ketosis at this time. There was some drop in VO2 needed by this time point, but nowhere like the drop by six weeks.

We can tell by the RQ values that at baseline (mean RQ 0.76) the subjects were oxidising a mixture of fat and carbohydrate (and some protein I guess). At one week there was more fat oxidation occurring (RQ 0.72). By six weeks we have the rather strange RQ of 0.66, lower than is produced even by the oxidation of pure saturated fat.

Oxidation of a fully saturated fat produces an RQ of 0.69. Hmmmmm...

I worked out that oxidising fat, on a simple mathematical basis, should give you a 5% improvement in ATP production per unit oxygen consumed compared with glucose. With Veech's increased Gibbs free energy of ATP hydrolysis while oxidising ketones we gain a combined 5% improvement in ATP supply alongside a decreased total ATP requirement. These are components of the decreased VO2 which didn't make it in to the discussion as they were either unknown (free energy of ATP hydrolysis) or hadn't been worked out (ATP per O2). Not a bad gain for six weeks of fasting. I can see, very clearly, that anyone with a chronic lung disease would be crazy to eat any way other than for a metabolism based on lipid oxidation with ketosis. It just makes sense.

I'll leave it now for this post and put up some ideas about the subnormal RQ figure as the next post.

Peter

Dave Asprey and Dr Veech

Dave Asprey has a very interesting extended discussion with Dr Veech on his Bulletproof website, mostly about ketones but also about the history of biochemistry and a number of other subjects. Dr Veech is very pro ketones while being surprisingly anti high fat diets, an interesting combination and clearly far from my own perspective. Much of the interview is simply fascinating in its own right but I'd just like to talk about the aspects with which I disagree. As one must.

Exclusive: Interview with Ketone Expert Dr. Richard Veech

The section of interest is around one hour five minutes in to the discussion. For those who would like some flavour of Dr Veech's uncomfortable stances on a fat based diet, cardiologists and cholesterol you can grind your teeth through the ten minutes leading up to that point. It's pretty obvious that Dr Veech has a lot of reading to do on cholesterol and cardiovascular health, should he so wish.

I had to correct a few relatively minor typos, nothing to do with what was said, just how it got written down, so I've put up the original text followed by my edited version. I've listened to this section three times now and I think my modified transcript is correct:



Original:

Dr. Veech: However, when you’re burning fat, you’re going through beta-oxidation. One reducing equivalent goes to NAD and one goes to pflavo protein. You’ve already lost 1/3 of your ATP in that step. Go back to your lennature Lehninger, beta-oxidation, you do one NADH, you do one NADH, you do one pflavo protein. You do that to keep from blowing the mitochondria up.

Tidied up:

Dr. Veech: However, when you’re burning fat, you’re going through beta-oxidation. One reducing equivalent goes to NAD and one goes to flavo protein. You’ve already lost 1/3 of your ATP in that step. Go back to your Lehninger, beta-oxidation, you do one NADH, you do one flavo protein. You do that to keep from blowing the mitochondria up.




I sold my copy of the biblical Lehninger at the end of my second year at vet school when we finished biochemistry as a subject in its own right. I have to say I really enjoyed the book. I also midnight question-spotted the urea cycle for my biochemistry written exam and it came up. Yeaha!

Sooooooo. Yes, beta oxidation (of saturated fats) does indeed yield one FADH2 which is embedded in a flavoprotein as well as generating an NADH. Electron transporting flavoprotein (ETF), which docks with ETF dehydrogenase, reduces the CoQ couple and omits pumping the four protons which could have been pumped had a second NADH been generated instead. My back-of-an-envelope calculations suggest an NADH could have been generated instead of the FADH2. This does indeed waste a four protons worth of the ATP which might have been generated.

And yes, the FADH2 is generated to stop damage to our mitochondria. So fats are bad?



With some slight discomfort I have to re-cite (yet again) the Protons thread. The whole point of generating inputs which reduce the CoQ couple is to drive reverse electron flow through complex I. Low levels to trigger insulin signalling, high levels to resist insulin signalling. H2O2 is the second messenger.

The waste of proton pumping by supplying FADH2 at the CoQ couple is offset by it being used to regulate the system. This applies to mitochondrial glycerol-3-phosphate dehydrogenase, driven by glycolysis, or ETFdh driven by beta oxidation of saturated fats. Both initially assist insulin signalling and, as substrate throughput increases, they facilitate resistance to the signal from insulin to accept more calories.

Another sooooooo. FADH2 is, I agree, wasteful but more importantly it also drives reverse electron flow through complex I. And undoubtedly you can have too much of a good thing. Waaaay back in the early Protons posts I spent a lot of time looking at FADH2:NADH ratios and decided that somewhere around palmitic or stearic acids there was a maximum healthy FADH2:NADH ratio, somewhere around 0.48. At that time Dr Speijer was kind enough to supply his paper looking at the development of the peroxisome in LECA, the Last Eukaryote Common Ancestor (not to be confused with LUCA, of the hydrothermal vents).

One major function of peroxisomes is to deal with very long chain fatty acids using a beta oxidation version which does not generate FADH2. Problem solved, no need to blow a gasket in our mitochondria. In fact the peroxisomes shorten VLC fatty acids to octanoate, much beloved of Dave Asprey and Dr Veech.

Minor aside: How might you explode your mitochondria if Dr Veech's concerns were correct re FFAs and his idea about FADH2 being used to reduce the supply of pumped protons from complex I? There is a technique to completely flood your mitochondria with NADH. It's called beta-hydroxybutyrate, particularly if supplied in large amounts from ketone esters. This enters the mitochondria using the monocarboxylate transporters, generates NADH as it converts to acetoacetate then goes on to generate three more NADHs from each of the two acetyl-CoA entering the TCA. These NADHs are potentially capable of pumping membrane popping numbers of protons through complex I, without concerning Dr Veech. And without actually doing any damage, that I can tell. End aside.

Next minor aside: Free fatty acids are not going to explode your mitochondria: Under ketogenic high fat eating there is a combination of elevated free fatty acids (happy happy), low insulin (so no loss of FFAs through insulin induced triglyceride formation), plenty of ATP in the mitochondria to allow uncoupling proteins to function (UCPs must have generous ATP on their mitochondrial matrix end to allow them to function) and those ad lib FFAs are necessary and available to actually carry the protons through the uncoupling proteins. FFAs are essential for uncoupling, no FFAs = no uncoupling, pax mtG3Pdh. FFAs = uncoupling = no exploding mitochondria. End second aside.

I'm left here with my view of a healthy metabolism as one based around beta oxidation of saturated fatty acids. Ketones as they happen, no stress. Nothing originating from the discussion has budged my entrenched position in the least, interesting though it has been to listen to.

Peter

When is a ketogenic diet not a ketogenic diet?

I've listened to a few youtube/podcasts videos recently. Seyfried, Veech and D'Agostino appear to besettled in to what looks like a "Ketone Ester" corner. There are many, many things which make me splutter a little in some of the things they say but I think it's hard to decry ketone bodies too badly. They clearly do things. It's quite possible that the main effect of flooding the TCA with acetyl-CoA is the inhibition of glycolysis. If it does nothing else, that seems worth doing.

The flip side is Ron Rosedale's view, shared by a few others. Towards the end of his presentation, largely about mTOR, he takes a position on ketones. I don't think he has anything against them per se, but what he really wants is a metabolic state based around beta oxidation of fatty acids. Just enough protein, minimal carbs, oxidise fats. If that throws off some ketones, so be it.

I clearly recall Wooo posting some time ago about the ketogenic diet for epilepsy and pointing out that what matters is compliance with the diet, not levels of a given ketone in blood or urine. If fatty acid oxidation dominates I'd be willing to bet the glial cells generate a ton of ketones which enter neurons without a dipstick in sight.

I think I might be in that camp. So I'm a little uncomfortable with medium chain triglycerides, octanoate alone, ketone salts and ketone esters. They clearly have benefits but they are not a route I would take currently.

I like ketones as a surrogate for fatty acid oxidation. Or should I say that I like beta oxidation, and ketones are a reasonable surrogate.

For the beta oxidation "camp" we have this paper:

Induction of ketosis in rats fed low-carbohydrate, high-fat diets depends on the relative abundance of dietary fat and protein.

It's a no nonsense sort of a paper. For the LC rats the diet was beef dripping. With added casein at 5.5%, 11.8% or 19.1% of calories and a few vitamins and minerals. The only carbs came from the vitamin/mineral mix. Anyone could get any rodent diet manufacturer to formulate it:

Rule one of a scientific paper: The methods must supply enough information to replicate the study.

Replication = validation. Without it your paper is worthless.

So rats on a LC diet are only in ketosis when over 90% of calories are supplied as beef dripping:

A BHB blood level of 28mg/dl is reasonable ketosis. That would be around 3.0mmol/l in new money. That's for the rats on 5.5% casein in their beef fat. All else was ns compared to the chow fed rats. There we have it. Decent ketosis in a rat is reliably achievable by feeding beef tallow. No MCTs, no ketone esters, no octanoate. Anyone could do this with their rodents. One niggle:

For the CICOtards: The LC animals were pair fed to the calories eaten by the chow fed rats, a feature of the paper I dislike a little. It's equal calories all round but the low carb rats probably ate less than their appetite would have dictated. This might have accentuated ketosis (but we'll never know...) and ad lib feeding might have blunted ketosis.

The weight gains themselves are fun:

Obviously the red squares are the ketogenic animals. There is a table of blood insulin, glucose, FGF-21 and FFAs but, well, we all know what the number have to be so there's not much need to go in to it in any detail. KDs work.

So if you want to know what a ketogenic diet does in a given medical condition, this is the one diet you have to use on a rat model. Maybe use butter instead of beef dripping (I'd prefer this for myself) but it looks like a gold standard to me... Ketones as a spin off of a whole body FFA based metabolism. The metabolic state is what interests me. Replicate at will.


Let's compare this with a ketone ester camp paper. This is the diet:

"...mice received KD-USF, a custom ketogenic diet designed by the authors and produced by Harlan Laboratories, fed ad libitum".

What's it made of? Dunno. Here are the macros:

What sort of fat? Dunno. Just fat. Maybe: Crisco? Fish oil? Canola? Coconut? Mmmm, butter? Replication anyone? If you can't replicate the study how can you tell whether the results were made up or real? Personally, I think the results are absolutely true. I have no doubt. Why? Because this is the level of ketones generated by the diet, where it says KD:

The ketogenic diet generated, estimated by zooming in on the above chart, something around 0.1-0.2mmol/l of BHB. No one would make up a figure that low, these are honest results. With added ketone esters we get up to almost exactly the level of ketones found in Bielohuby's truly ketogenic tallow fed rats, without the crippling expense of the ketone esters.

People shouldn't get me wrong. I have nothing against trying to use a ketogenic diet for management of cancer. I even think using ketone esters might be reasonable for folks who can't cope with cream, butter, eggs and a wide variety of meats and non starch veggies.

What I would prefer is for a diet described as ketogenic to actually generate some ketones. You cannot describe a diet generating 0.1mmol/l of BHB as ketogenic! Especially when close on 3.0mmol/l is easily achieved on a beef tallow based true ketogenic diet. It's not exactly surprising that adding 3.0mmol/l BHB derived from ketone esters should out performed a non-ketogenic "ketogenic" diet for cancer management! And the non ketogenic high fat diet did help a little, presumably by eliminating starch triggered insulin signalling...

I was a bit shocked that non of this was discussed in the discussion. Being driven by a love of ketone esters is no excuse for sloppy science. When you are on the winning side there is no need for this.

Peter

Would Franklin have taken a statin if they had been available in the 1800s?

The Franklin expedition of 129 men perished in the Arctic, primarily of scurvy and related illnesses, in its entirety. I've been reading Stefansson's retrospective account and speculation written in the 1950s. This paragraph stuck out as a nice warning, still applicable to the lipid hypothesis today, which we see crumbling before out eyes. How many have died prematurely of medical dogma?

"We concede that Franklin had the excuses which many others have used; that medical men told him nothing about meat being preventive of scurvy, and that they told him instead about lime juice and lemon juice as preventatives and curatives. But we return to our point that a man who makes exploration a profession, as Franklin had done, has no business to sacrifice his men to the dogma of current therapeutics when he can divide the entire literature of his own craft into two chains of events; the expeditions which had a good deal of fresh food [meat] and little or no scurvy; and those which had little or no fresh food and much scurvy".

Fat vs sugar. PUFA vs saturates. Statin vs giving the finger to Keys for the buried Minnesota data.

Peter

Glucosamine and aged mice

It would appear that glucosamine, the arthritis neutraceutical, promotes longevity.

D-Glucosamine supplementation extends life span of nematodes and of ageing mice

This paper is a mix of C. elegans and mouse work. Most of the findings are reasonably transferable but the core finding, that a metabolite of glucosamine inhibits glycolysis, was actually demonstrated in the worm section. Extended longevity was found both in C. elegans and ready-aged mice.

Glycolysis inhibition and life extension in C. elegans:

And for longevity in already aged mice:

It's worth noting that glucosamine usage in humans is observationally associated with extended lifespan.

To me the core finding is that the inhibition of glycolysis extends life. I like that. In the mice it was also found to cause insulin resistance, mild at the dose rate used in the paper. However I would expect resisting insulin to be associated with extending lifespan. I'm quite keen on extending my own healthspan. The longer this goes on, the happier I'll be. My plan is resist insulin.

Now. Is there any other simple way of inhibiting glycolysis which might rival extended glucosamine administration?

If we go to Veech's isolated, perfused, working rat hearts (again) we can see some interesting things:

I suppose the first thing we have to say is that the heart works quite well on the utterly non physiological substrate of isolated glucose.

Next is that insulin decreases glycolysis compared to this baseline. The increased glucose ingress to the cell is diverted to glycogen synthesis while insulin simultaneously increases the efficiency of the electron transport chain. So net flux through glycolysis drops from 5.6 to 3.8 micromol/min/ml. Ketones (a physiological mix of AcAc and BHB) drop glycolysis from the baseline 5.6  down to 1.7micromoles/min/ml, which I find quite impressive.

As always, Veech maintains a phobia about fat so we have no data about what the addition of fatty acids might do to glycolysis. Enough said that ketones suppress it quite well. Veech has a detailed discussion of the various redox couples which control this process. To a simpleton like myself we can just view the situation as observing when ketones flood the TCA with acetyl-CoA there is nowhere for glycolysis products to go to, so it stops. The effect of redox couples on the energy yield of ATP hydrolysis is a separate consideration.


Let's summarise: Ketone bodies markedly inhibit glycolysis. Note to push-biking self: They also promote glycogen formation.


Glucosamine drops glycolysis in C. elegans by 43% and gives a measurable longevity gain. Ketones in an isolated perfused working rat heart drop glycolysis by 66% and appear, in many papers, to have some favourable effects on many of the problems which come to us with age. I find that interesting.

Peter

Alcohol and fructose are the same to your liver

From Liz Miller via Facebook.

Alcoholic Liver Disease: Update on the Role of Dietary Fat

"The protective effects of dietary saturated fat (SF) and deleterious effects of dietary unsaturated fat (USF) on alcohol-induced liver pathology are well recognized and documented in experimental animal models of ALD. Moreover, it has been demonstrated in an epidemiological study of alcoholic cirrhosis that dietary intake of SF was associated with a lower mortality rates, whereas dietary intake of USF was associated with a higher mortality".

My italics.

Brief note to Saturophiles and Cholesterophiles:

I think we can say that we have won.

Peter

Dairy and diabetes

Mozaffarian has published this nice observational correlation between three markers of dairy consumption and subsequent onset of diabetes over the following 15 or so years.

Circulating Biomarkers of Dairy Fat and Risk of Incident Diabetes Mellitus Among US Men and Women in Two Large Prospective Cohorts

Any of the three markers is associated with a roughly halving of the incidence of diabetes. I sort of like this, living largely on bulk calories from dairy myself. I also like the size of the effect. If you consider how many people are in the process of developing diabetes in the USA alone, halving that incidence might make a significant contribution to reducing suffering.

If you eat a gram of C15:0 fat, what else comes bundled along with it? Well, in Swedish milk fat there is about a gram of C15:0 in 100g of total fat. That total fat is made up of 70% saturated fats, mostly palmitic acid, a decent dollop of stearic and myristic acids plus odds and sods of shorter chain saturates. These fats might be what reduces the diabetes risk. What makes me think that, other than my biases?

If you feed a normal Bl/6 mouse 40% of its calories as stearic acid, what happens to its blood glucose level? Taken from fig 2.3.1 part B. After 10 weeks the blood glucose of a normal mouse will be significantly lower than if it had been fed standard CIAB or 40% of an oleic acid/PUFA mix. That will be the red arrow:

The blood glucose lowering effect even occurs in db/db mice, a routine model used to vaguely represent T2 diabetes, green arrow. That's all fine and gives some sort of suggestion that it might be the saturated nature of dairy which is protective against diabetes. But why should this occur?

I'm drawn back to the perfused isolated pancreas and the insulin response to physiological levels of glucose in the presence of various fatty acids. This is the image I'm thinking of, from The Insulinotropic Potency of Fatty Acids Is Influenced Profoundly by Their Chain Length and Degree of Saturation:

Notice the marked but transient spike in insulin when glucose is raised from 3.0mmol/l to 12.5mmol/l, most obvious in the black squares representing stearic acid as the background FFA (palmitate is the black triangles). After the spike, which I think represents the first phase insulin response, there is a steady climb in insulin, equivalent to the second phase of insulin secretion. Obviously this is needed because it's an isolate pancreas prep, glucose is fixed at 12.5mmol/l in the perfusate. If the first phase insulin response does its job in real life the systemic circulation (and pancreas) would never see 12.5mmol/l of glucose. The surge of insulin would hit the liver and interact with the insulin receptor. Two things follow on from this. Most insulin would be metabolised following interaction with its receptor, so insulin would never flood the systemic circulation. Second effect is that insulin/insulin receptor activation would shut down hepatic glucose output while the Glut2 transporters continue to pretty well clear the portal vein of glucose.

So a first phase insulin response is designed to protect the systemic circulation from both hyperinsulinaemia and hyperglycaemia. That is its job.

If you want to obliterate the first phase insulin response what you need to do is to reduce reverse electron flow through complex I. Just take a peek at the open circles (oleic acid) and, even better, the closed circles (linoleic acid). For a healthy pancreas, from a healthy rat, you can eliminate the first phase insulin response to hyperglycamia just by choosing your background FFA.

Summary:

Arterycloggingsaturatedfat first phase insulin response 16ng/fraction

vs

Hearthealthypolyunsaturatedfat first phase insulin response 2ng/fraction.

Want to be fat? Use your second phase insulin response in the systemic circulation to pack fat and glucose in to adipocytes. But you must avoid the first phase response because this will keep glucose in the liver as harmless glycogen.

Try using sunflower oil or corn oil as advised by the Food Standards Agency. When you get so fat that your adipocytes start to spew unregulated FFAs, you can be a diabetic (congratulations!). You owe it all to your cardiologist. Or the FSA. Remember who to contact when you get your first diabetic amputation.

Peter

Oh, picked up this quote about dairy and heart disease from Tom Naughton's blog:

"Rather than suggesting that the saturated fats in dairy products are harmless, Aslibekyan and co-author Ana Baylin, an adjunct assistant professor of community health at Brown, hypothesize that other nutrients in dairy products are protective against heart disease, for all but perhaps the highest dairy consumption quintile in their study. The potentially beneficial nutrients include calcium, vitamin D, potassium, magnesium and conjugated linoleic acid (CLA)".

The authors are completely wrong in the interpretation of their own data. On every front. Saturated fats are NOT harmless. Shout it from the roof tops. THEY ARE PROTECTIVE.

"calcium, vitamin D, potassium, magnesium and conjugated linoleic acid (CLA)"?

Bollocks. Ask the mice on stearic acid.