Monday, 20 September 2010

Paleo suit

I did not expect this to happen. I have never had probems buying suits before, except that I always thought that I would need a smaller size . This has changed now when I was told that the store is not selling suits with trousers and jackets differing by two or more sizes! When I was trying on the suits, when the trousers were just right, the jacket was too small and when the jacket fit, the trousers were 8 inches too big. They allowed one size differences, but would not let me pick from suits two sizes apart.

Now, not only my BMI is wrong, but also by body proportions are abnormal. And what I save on the dentist, I will have to spend on bespoke tailors.

Beary good fat

This was in one of the episodes od Planet Earth with David Attenborough: grizzly bears feeding on moths. Actually, pigging out. They took the trouble to move rocks of considerable size to get at the hiding moths. What was so good about the moth? Fat. Unfortunalty I could not find this bit on YouTube, but here is some info on the phenomenon.

Which makes me think that indeed fat moths and caterpillars could have been a staple in some necks of the wood, along with molluscs. Why bother hunting lean meat when you can just gather the fat a la Mopane! And the fat would be mostly unsaturated (keeps the insect from freezing) with plenty of omega-3. No need for cod liver either.

If environmental issues were to prevent everybody from eating animal protein, farming caterpillars could be the answer. Not necessarily more disgusting than what many people consider food these days. Of course, the caterpillars should not be fed soy - that would be gross.

Wednesday, 15 September 2010

European hunters-gatherers and cardiovascular risk

I discovered this on an anthropology blog, and the link to the original release is here.

In summary, men with the I-haplogroup have a higher risk of CHD. These are people who most likely migrated to Europe about 25,000 years ago, long before the first farmers. Chances are they are also less adapted to Neolithic foods.

And there are resons to think that mtDNA also plays a role in adaptation to Neolithic food, as well as glacial cold. Perhaps those of us who have genes of ancestral H-G Europeans fare better on high fat than the later immigrant farmers?

It would be interesting to compare susceptability to chronic diseases in U (first wave of Paleo Europeans), H (second wave) and later Neolitic farmers (J, T).

Thursday, 9 September 2010

AGT: a marker for carnivory

It looks that there might be a marker for the adaptation to predominantly carnivourous or herbivorous diet in our ancestors. It appears that alanine-glyoxylate aminotransferase (AGT) targets two different intracellular locations. In the carnivores, AGT targets primarily mitochondria; in plant eaters, it targets the peroxisomes. Humans are omnivores and there are polymorphisms in both directions.

Interesting story about adaptation to herbivory in taxonomic Carnivora, also explaining the biochemistry. Would be interesting to see the oposite in the polar bear.

The autors cite that:
"Although in most normal humans AGT is peroxisomal, in many PH1 patients AGT is mistargeted to the mitochondria (Danpure et al. 1989). Mistargeted AGT remains catalytically active but is unable to fulfill its metabolic role of glyoxylate detoxification efficiently. As a result, oxalate synthesis increases and calcium oxalate crystallizes out, usually as stones, in the kidney and urinary tract."

Interesting, kidney stones on a vegetarian diet in people who should be eating meat instead? But it also suggests that humans might be omnivores more on the plant side...

But it is more complicated than that.

In another comparative analysis, which essentially supports the association between AGT and diet across mammals, the authors state that:
"The human, in fact, is remarkable because, after having lost the ability to target AGT to mitochondria following a single mutation to the more 5′ ancestral translation start site (Takada et al. 1990), some individuals have reacquired the ability to target a small amount of their AGT back to mitochondria. However, this is not owing to reintroduction of the ancestral MTS back into the open reading frame. Instead, it is owing to the presence of a very common polymorphism which creates a new MTS in a region downstream of the ancestral MTS (Purdue et al. 1990). Whether this reacquisition of mitochondrial AGT targeting in some humans is related to increased meat-eating is unknown."

Also here:
"Some evidence to suggest that populations with greater recent ancestry of meat eating (eg. the Saami) have higher frequencies of the allele favoring the “retargeting” of enzymatic activity to the mitochondria.
The entire article is really worth reading.

So, how do I get my AGT tested?

EDIT: Having written the above I did some more browsing and came across a highly recommended article from BeyondVeg. The autor is making a strong case against veganism, but the evidence for rapid evolution and adaptation, at least in some ethnic groups, could also support the argument for some Neolithic foods in the diet:

"A recent analysis of a major genetic database - the HapMap SNP database - has shown that human evolution has accelerated dramatically in the last 40K years BP, with adaptive evolution in the last 10K years BP occurring at a rate >100 times the rate that prevailed in most of human evolution (Hawks et al. 2007, Hawks 2007). There are two primary drivers for this phenomenon: 1) the major increase in human population caused by the agricultural revolution – a larger population base allows for a larger number of genetic mutations, 2) diversity in human cultures – diets, environments – created numerous environments with different selective pressures to filter the mutations.

The preceding suggests that more human evolution has occurred in the time since the agricultural revolution began, ~10K years BP, than in the 1 million years that preceded the date 40K BP. The conclusion here is that humans are still evolving, and very rapidly, i.e., we are very much a “work in progress” in evolutionary terms."

I like the bit about chitinase, though this is probably an old adaptation. Would chitin count as fiber? Mopane anyone? Should be high in omega-3 if leaf/grass-fed. Excellent source of protein, but I would skip the porridge in the recipe. Yummy.

Wednesday, 8 September 2010

Adaptation to Neolithic diet: C282Y and H63D

Vegatarians and vegans often use arcane methods of food preparation or supplementation to make sure their diet is complete. This is clearly an unnatuaral way to make the supposedly natural plant based diet to work. WAPF adherents can also go to extreme to make grains lose most of its toxicity.

But sometimes the meat eating Paleo crowd uses a simillar method to make sure that the unsuitable diet is tolerable: they suggest bloodletting for iron overload. Indeed, giving blood is effective for haemochormatosis and is also laudable, but I doubt it is natural on a regular basis. Perhaps the meat rich diet is just as "unnatural" for sime people as vegetarian or vegan one is in others?

I took a closer look at heamochromatosis. It appears that about a quarter of people of European heritage are carriers of C282Y or H63D mutations which markedly increase the risk of iron overload. These mutations most likely occured some 60 generations ago as a response to grain-based diet, associated in turn with risk of iron deffciency. The mutations occured in Celtic and/or Viking tribes and spread across Europe. Apparently the Southern farmers did not have this trait due to vegetarian sources of iron (or they were not "lucky" enough to mutate). The mutated genes were selected for during the Bubonic plague as low iron in macrophages (due to rapid storing in tissues) offered protection against Yersinia pestis.

All this means that about a quarter of Europeans (more in Ireland, Scotland and Scandinavia than in Southern Italy or Greece) should worry about iron overload, and perhaps stay clear from too much meat.

I suppose they can still be Paleo, eating seafood, snails and other invertebrates, but possibly they would also be more adapted to grains?

One way to find out is to do the tests for Total Iron Binding Capacity (TIBC), Serum Iron (SI) and Serum Ferritin (SF), as apparently genetic testing is unreliable - typically ony those two genes are tested while 40 mutations can lead to iron overload - and expensive.

To me it looks like those people are stuck. Going back to meat-based Paleo is risky, but grains are without doubt suboptimal, even if some adaptation occured. What if there are some other mutations responsible for other metabolic pathways which helped our ancestors adapt to Neolithic diets, but with serious side effects in chronic diseases and decreased longevity? Saturated fat can be a good example. Or gluconeogenesis. Or glucose transport?

What if those genes can be modified epigenetically and our grain eating grandmother had greater impact on expression of our metabolic enzymes than hundreds of thousands of Paleolithic evolution?

I am worried that the Paleo community is starting to become as dogmatic as the entrenched vegetarians, who know better and do not even engage in constructive discussion.

In science the only way to move ahead is to constantly question our hypothesis, try to falsify it. I failed as a vegetarian scientist, but this time I am going to be more careful.

Wednesday, 1 September 2010

Lamarck again

I keep thinking about evolution and would like to have the time to explore all things Lamarckian a bit more. This is definitely crucial in the paleo context and it seems that thinking in the paloesphere has been limited to Darwinian theory.

Here is a popular text from Newsweek. Preciusly I also cited an article on Lamarkian medicine. Recently medical relevance of Lamarck's theory has been highlighted again. I also recommend this paper, a good overview of the problem, which also gives credit to Darwin for his "Lamarckian" theory of pangenesis.

If I had the time I would also read Ross Honeywill's book, which clearly looks interesting, though it has to be shipped from Australia.

Understanding this is absolutely essential as it is conceivable that some of us are already adapted to Neolithic food/lifestyle and changing back to paleo could actually be maladaptive! Or perhaps Lamarkian mechanisms allowed adaptation but only suboptimal, relevant to reproductive success, but not optimal for, say, vitality and longevity. It would be different in different populations and even individuals and we would need to find out empirically what works best, though we have only one life for the experiment.

Apparently, some characteristics become inherited after 5-10 generations and this is known as Baldwin effect. Importantly, inheritance requires some compensatory mechanism, such as hypertrophy after exercise or activated metabolic pathway after change in diet. Simple cutting of rats' tails would not make their offspring be born without tails (same with circumcision).

I guess one place to look for would be polymorphisms in metabolic enzymes in populations with different exposure to Neolithic agents.

Can all breeds of dogs be switched to a diet suitable for a wolf? Would that affect their fertility, health, life span? [Dogs have been fed meat and bones for most of the history with grains introduced very only recently, but grains were always cheaper than meat...].

How about polar bears, can they go on a grizzly diet? Polar bears are very relevant, as they apparently switched to a completely different diet during some 10K years! But in this respect Italian wall lizard is even more impressive, whether it was Lamarck or Darwin at play.

It is pure heresy, but this is what is making it so fascinating, particularly if you have read Paul Feyerabend or Thomas Kuhn.

Think of the societal implications.

But natural selection could also work during relatively short time, as in the case of Tibetans and their adaptation to high altitude.

Michel Montignac est mort

I am not an expert on the Montignac diet, but his death prompted some of my friends to comment on my eating habits. This made me have a look at what this diet was all about.

It appears, it was (it is) a high protein, low fat and moderate carb regime. If people on this diet want to avoid being hungry without putting on weight, they are bound to overdo protein. And what kind of protein would that be? Mostly highly processed animal protein loaded with salt, nitrates, benzopyrens and other carcinogens and oxidized fats (even lean meat contains fat and aged cheese is just loaded with oxidized lipids). Montignac advocated against mixing carbs and fats, but did not see any problems with mixing carbs and proteins, hence Maillard reaction was likely quintessential, as it is in tasty French cousine in general.

And much grain fed meat plus olive oil means loads of proinflammatory omega-6.

On a video from March this year, the guy does not look healthy to me. His skin looks too aged for 66. AGE?

And the high protein itself, with mTOR. If the guy did not do any fasting, or at least skipped some meals "warrior style" (he actually recommended 3 meals a day), then perhaps his mTOR was the driver?