Monday, June 16, 2014

Slim mice which don't fart

Germ free mice are quite interesting. I suppose that the first thing we can say about them is that they don’t have any bacterial fermentation in their gut to produce flatus. As a side issue of some interest is that none of their intestinal mucosal cells ever sees any acetate, butyrate or propionate derived from microbial fermentation of fibre in the gut. They seem rather happy that way. You could also say the same about their liver, it too never sees any SCFA bacterial fermentation products. They stay slim.

Ancient history tells us that germ free mice live rather longer than their more flatulent counterparts. I find this quite interesting.

Of course longevity is a relative term and perhaps ought to be qualified a little. We should actually say that they live longer than conventional mice, provided you feed them. Not feeding germ free mice is quite bad for them, they die under starvation significantly sooner than conventional mice do, at higher bodyweight and with more fat reserves.

That was the state of our knowledge at the end of the last century.

In more recent years the mechanisms for this failure to cope with starvation has become a little clearer. Germ free mice are insulin sensitive. They stay that way pretty much whatever you do to them in terms of diet. They stay that way even if you starve them. That, in terms of survival, is a booboo.

There are at least two techniques available via the gut microbiota which might improve the ability to survive starvation and which are gifted to germ free mice by smearing them with pooh from a conventional mouse. One is endotoxin, a subject I suspect I will come back to. The current one, for this post, is short chain fatty acids.

Bacterial fermentation of fibre produces those miracle agents of gut health and general goodness; acetate, butyrate and propionate. These act through a G protein coupled receptor on enterendocrine cells to promote fat storage. This is the Gpr41 receptor. Needless to say the enteroendocrine cells are the same cells which secrete FIAF, as in the FIAF series of posts. The two are possibly related. Given a little effort we could, by looking at conventionalisation of germ free mice, make a good guess about how much of a mouse’s fat belongs to the mouse and how much belongs to its gut microbiota.

So the fermentation products of bacteria promote fat storage when germ free mice are conventionalised. But no one seems to think that a lack of fat was the reason for germ free mice dying sooner under starvation. So what is the other effect of SCFAs, other than a bigger butt?

The gift of ketosis. Germ free mice are crap at ketosis. It’s not that they can’t do it, it seems to be more like a lack of practice. Acetate and butyrate are particularly ketogenic and hit all sorts of signalling systems in the liver to up regulate ketone generation in conventional mice. Of course germ free mice on standard crapinabag never send acetate to their liver, so their liver never up-regulates the correct PPARs to do ketosis. Putting germ free mice on to a deeply, deeply ketogenic diet teaches them how to make ketones and they become rather good at it.

Under starvation the myocardium of a germ free mouse continues to metabolise glucose, despite free fatty acids being available. Crawford et al consider the myocardium to be fairly representative of many of the glucose using organs in the body. They view ketones as an alternative energy source to glucose under starvation. While no one would argue with this, the possibility which fascinates me is that ketones are turning off glycolysis to spare glucose for the brain when fatty acids alone don’t do this. They appear to be a core component of physiological insulin resistance.

Whether these ketogenic germ free mice are able to extend their time of death to that of starved conventional mice is not a question which any modern ethics committee will allow you to answer today, unless you have a damned good reason. But I suspect the answer is yes.


Addendum. If you accept that perhaps SCFAs expand your butt via Gpr41 (we are not, after all, germ free mice freshly smeared with conventional mouse faeces) guess which metabolite is a direct antagonist to SCFAs at Gpr41? Clue, it's that the beta hydroxylated derivative of butyric acid. I love stuff that makes sense.


Kindke said...

Peter I just want to bring your attention to this paper, very interesting.

Apparently DNL in the liver is absolutely critical for activating PPAR alpha and ketogenesis, if you knock out fatty acid synthase in the liver, fat flowing in from adipose tissue fails to activate PPAR alpha.

In this respect SCFA DNL in the liver might actually be a good thing.

Stipetic said...

Seems like SCFAs prevents butt expansion via Gpr41, while b-HB, specifically, promotes it. This is what these guy's 2014 paper seems to imply. This doesn't seem to jive with your addendum. Did I misread it?

Peter said...

Stipetic, the review is very, very carefully worded:

"The body weight and fat pad weight of Gpr41 knockout mice are significantly reduced compared to wild-type mice, and this difference is abolished in germ-free conditions"

To clarify this statement: Removing the SCFA (Gpr41) receptor keeps you slim. The "abolished" means that both Gpr41 k/o and wild type mice are all slim, not equally fat.

My contention is that B-OHB will antagonize Gpr41 and mimic Gpr41 k/o or germ free wild type mice, ie keep them slim.

As in ketogenic dieting.

The difficulty following the tortured argument is a glimpse in to the cesspit...


tiago said...

Dear Petro, long time reader of your blog,

I was diagnosed with Bicuspid aortic valve, calcified with mild regurgitation, and mild ascending aortic dilatation (37 mm). I am 35 years old.

Do you or any of the fellow readers have any ideas on what could I do to postpone the degeneration of the native valve?

Could ascorbic acid supplementation be a good idea for the enlargement of the aorta (deficiency of collagen/fibrillin1)?

I know the ultimate treatment will be the open-chest surgery.... but I would like to bear another 35 years first...



Jack Kruse said...

Tiago you need a lot of DHA and Vitamin K2. But you must make sure your Vitamin A and D cycles (brain chromophores) are optimized for it to give 35 yrs before the chest is cracked. You need to optimize your circadian cycles to do this. NAD+ is a big part of that. Adding resveratrol also helps. Optimizing your water is key. It helps your mitochondria in a big way. You might have a look at calories proper current blog on why this is important. To reverse dystrophic calcium deposition in cases I use D-Glucosamine in patients. It inhibits glycolysis is by inhibiting hexokinase (also the liver analog, glucokinase). This impairs glucose metabolism and results in the cell “switching” over to amino acid metabolism to produce energy. Thus D-Glucosamine is a “metabolic switch” that converts “Warburg-type metabolism” in the cell (i.e. aerobic glycolysis in the presence of adequate oxygen) over to “protein metabolism”. For every increase of 10 micrograms in the amount of vitamin K2 consumed daily, the risk of developing coronary heart disease (CHD) drops by 9 percent. This statistic was noted as a result of a cohort study from the Netherlands evaluating the dietary vitamin K intakes of 16,057 post-menopausal women and their association with the incidence of CHD. Many people/doctors seem unaware of this data. When I see a low Vitamin D levels I usually tell the person with bad bones, a bad heart or bad teeth to increase their vitamin K2 200mcgs for every 1000 IU of D 3 they are supplementing. This is the magic that helps them “begin” to rehydrate.
he VKOR is the crucial enzyme in vitamin K metabolism in humans. It enables Vitamin K’s recycling after it has been oxidized in the carboxylase reaction through which it activates Gla-proteins. KH2 is a cofactor in this crucial step. Vitamin K2 carboxylates the Gla-proteins of osteocalcin to stimulate osteoblasts to make new bone and prevent osteoporosis. Because of the VKOR recycling, the human dietary requirement for vitamin K is extremely low. It is just 45 mcg/day when things are working optimally. Of course if the gut is not working well for any reason, the dietary needs can skyrocket. The gut microbiome can make vitamin K, provided there is a normal gut flora state. FIAF is a big player. If one does not have a gallbladder, this can present a problem in absorption of K2. Although the liver is the main storage site, vitamin K2 is also found in some extrahepatic tissues, like bone and the heart . The cardiac valves are a rich source of Vitamin K2 in normal humans. So if your missing a gallbladder it predicts you are risk for aortic stenosis and it also means you'll have high estradiol, low testosterone, low Vit D and high SHBG all along with a very low K2 level in your aortic valve. Hope this helps.

George Henderson said...

Return of superoxide!

Galina L. said...

I think well-absorbing magnesium supplements are the must in your condition. I would even get the injections and use a trans-dermal supss as a cream.
Jack is right - Vitamin K2 is very important for having calcium in the right places. There is even a therm "calcium paradox". "simultaneous excess of calcium in one part of the body (arteries), and lack in another (bones) –which may occur even in spite of calcium supplementation - is known as the Calcium Paradox. The underlying reason is vitamin K2 deficiency, which leads to significant impairment in biological function of MGP, the most potent inhibitor of vascular calcification presently known. Fortunately, animal research showed that vascular calcification might not only be prevented, but even reversed by increasing the daily intake of vitamin K2." - from the Wiki article about K2.
After reading about mysterious "Activator X" turned out to be a vitamin K2 on WPF site, I always pay attention to the quality of my butter and cream:

They also claim that K2 could even block the substance which causes arteries classification
" Warfarin, which inhibits the recycling of K vitamins40 and the conversion of K1 to K2,64 causes calcification of the tunica media in rats within two weeks....
Large amounts of vitamin K2 completely inhibit the ability of Warfarin to cause arterial calcification in rats. Vitamin K1, by contrast, has no inhibitory effect at all.21 Researchers from the University of Maastricht recently showed that both K vitamins can reverse calcification that has already occurred in Wistar Kyoto rats.65"

I relay only on the right choice of foods in order to get enough of vitamin K2, but most probably I should add supplements to it, considering the absence of a gallbladder and the family history of a heart decease.

gunther gatherer said...

"So the fermentation products of bacteria promote fat storage when germ free mice are conventionalised."

The estimates of the number of strains of bacteria in the gut range from 1,000 to over 30,000, depending on the microbiologist you talk to. About 95% of these strains are not even able to be cultured in a lab due to specific pH, temperature and CO2 requirements, let alone identified. Most of them don't even have names yet. But that hasn't stopped you from assuming that "bacteria" (as if that were one thing) somehow causes bodyfat gain. And of course fiber and carbs feed your dreaded bacteria, so you made it all work into your dogma nicely.

The gut microbiome is WAAAY more complex than that. Some bacteria are possibly causing fat gain, but some are also fighting it. It is the balance between all of them that counts. You can't just say the equivalent of "bacteria (presumably caused by dreaded fiber and carbs) causes bodyfat gain". Very simplistic and misleading.

In short, you are way out of your depth when you blindly reduce this topic to the word "bacteria", as if it were just one animal wreaking havoc on the body.

If you had said something like "overgrowth of Bacteria X is associated with increased bodyfat" or something like that, you'd at least sound somewhat scientifically grounded instead of an internet crackpot. You have no culprit and you have no pathway. As usual, you only have the tired old Low Carb Dogma.

john said...


I'm hesitant to engage you, but how did you conclude that he did "blindly reduce this topic to the word 'bacteria'"?

This was said: "'The body weight and fat pad weight of Gpr41 knockout mice are significantly reduced compared to wild-type mice, and this difference is abolished in germ-free conditions'

To clarify this statement: Removing the SCFA (Gpr41) receptor keeps you slim. The "abolished" means that both Gpr41 k/o and wild type mice are all slim, not equally fat.

My contention is that B-OHB will antagonize Gpr41 and mimic Gpr41 k/o or germ free wild type mice, ie keep them slim."

Did you read the post and/or comments or just search for a phrase you didn't like? Nobody is claiming to have detailed information about every bacteria in the gut.

gunther gatherer said...


Nope, there were lots of phrases I didn't like. But this one about bacteria was the most egregious, and it showed nicely how everything can be reduced to "carbs make you fat" in Low Carb Land.

Lady Gray said...

Peter's addendum speaks of butter. Is there anything other than butter that will do the same good things as butter? I seem to have a problem with casein, and even after clarifying the butter I still get a reaction to it.

tiago said...

Thanks Dr. Kruse and Galina L. Much appreciated ideas/suggestions!

Ilaine Upton said...

Galina, Dr. Price thought people should consume high vitamin butter oil mechanically separated by centrifuge from butter from grass fed cows. I have no idea whether he is wrong or not, but I eat a teaspoon every day, along with a teaspoon of fermented cod liver oil. Can't hurt, might help. Casein free for Lady Gray.

Yes, yes, Vitamin K. K-1, MK-4, MK-7, all together. Some brands to look at, Koncentrated-K, Life Extension.

Galina L. said...

I just put reasonable amount of a grassfed butter on my veggies and eggs(I usually get pastured eggs). I don't know would Dr.Price approve of my butter, what else could I do? I also buy canned cod liver in a cod oil in Eastern European stores, mix the content, put in a freezer and eat small tsp of it almost daily. Hope it is not too much or too little.

Melchior Meijer said...

Hi Peter,

These folks at Maastricht University are extreme lipophobes (think Mensink), but I cannot find the dirty tricks they must have used in the experiments outlined in this paper. Here is an example. Prolonged fasting induces mitochondrial dysfunction in healthy young humans?

In the present study we evaluated the effect of prolonged fasting on skeletal muscle mitochondrial functional capacity in humans in order to examine whether the mitochondrial dysfunction that is frequently reported in insulin resistance and type 2 diabetes mellitus can be a consequence of lipid-induced insulin resistance, rather than a cause. In contrast to the hyperglycaemia and hyperinsulinaemia accompany- ing ‘energy excess’-induced insulin resistance (lipid infusion, high-fat diets), pro- longed fastinginduced insulin resistance is associated with hypoglycaemia and hypoinsulinemia. Moreover, prolonged fasting-induced lipid accumulation and insulin resistance areconsidered to be a functional physiological response. Thus, reduced insulin sensitivity saves carbohydrates for the central nervous system, being obli- gate for glucose and not requiring insulin for its uptake, while increased lipid avail- ability at the same time can serve as a direct available energy source for the muscle and is paralleled by an enhanced fat oxidative capacity (12).

Therefore we anticipated that skeletal muscle mitochondrial function would not be impaired in this model, unless mitochondrial function is impaired by factors that are secondary to the lipid-induced insulin resistant state. Intriguingly, we found that only 60 hours of fasting in humans was accompanied by an overall reduction in skeletal muscle mitochondrial capacity, which was not explained by changes in mitochondrial density.

George Henderson said...
This comment has been removed by the author.
George Henderson said...

@ Melchior,
in ruminants, hepatic lipidosis from NEFAs and ketone results from negative energy balance in the peripartal period.

Liver is a pivotal organ regulating the metabolism of lipid, carbohydrate and protein. Negative energy balance during the peripartal period, i.e. 3 weeks prior through 3 weeks after parturition or nutrient restriction decrease the concentration of blood glucose and increase concentration of circulating nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BOHB) in the blood. Accumulation of triacylglycerol in liver often follows.
So it can be done, but I suspect it's adaptive in this case, and the liver is reabsorbing excess stored energy that's been released by adipocytes.

Peter said...

Melchior, the research looks good to me. I would argue with semantics. They use the term "dysfunction" to mean that the mitochondria are dysfunctional. I prefer the term adaptation, as the mitochondria clearly adapt to the circumstances in which they find themselves.

Within the normal range of fatty acids outside of ketogenic eating or starvation beta oxidation is a supply controlled system. Remove the brakes and push FFAs to 20mmol/l (20,000micromol/l, wow!) and you have available an essentially unlimited supply of ATP. If there were no limitation to beta oxidation there would be a massive ATP oversupply. Limiting ATP production to needs might well involve down regulating fatty acid metabolism w/o removing mitochondria. I would call this adaptation.

I just loved the follow on chapter with no evidence of inflammation from these huge levels of FFAs and the conclusion that elevated glucose is the bugbear.

Semantics and mindset. Their concepts look good, especially when they accept massive elevation of FFAs as non inflammatory. I really like that.


Peter said...

Kindke, very interesting idea, not had time to check out the paper but reminds me of insulin, DNL in adipocytes and the use of the double bond from delta 9 desaturase to signal insulin sensitivity. MCTs convert to palmitate as well as ketones, wonder if they are related to the SCFA system?


Melchior Meijer said...

George, thanks for your explanation.

Peter, wow, that makes al lot of sense :-). They framed it so cleverly, that this possibility didn't even occur to me.

Maybe slightly off topic, but this IHMC-lecture by Dominic D'Agostino is very fascinating:

Raphi, is that you over at TGD :-)? Looking forward to his response.