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Originally Posted by aj_cohn
I find it difficult to accept that it takes 40+ years to show signs of nutrient deprivation. I know one lifelong vegan whose only sign of deficiency at age 63 is a "middle-aged" spread.
On the basis that it's one of the preferred foods of the heart. I'll have to dig up my reference for that.
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On the first point... okay, you hadn't specified 40 years.
My varying times for nutrient deficiency to show up is based on various accounts by ex-vegans that I've read over the years. 40 years does seem like a stretch. But other than b12, human beings do have the ability to get or synthesize pretty much all of the essential nutrients from various plant sources. It might not be ideal, it might not be optimal, not everybody might thrive on it. There are populations that live almost exclusively off of sweet potatoes, cassava and other starchy tubers. It's not optimal, you'll find studies on kwashkiokr etc. done on the children in these places.
Maybe your vegan friend is eating bacon when nobody's looking? Or just supplementing b12.
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Bonnie — but how is it possible that he's healthy? The keystone of low-carb and paleo eating is the thesis that a human's diet should be at least 50% fat (mostly from animals) to align with our evolution and meet our nutritional needs. If that's not true, then the entire paleo paradigm as a broad-based recommendation for health falls apart.
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This is why I don't ascribe to Paleo as a "broad-based recommendation for health." I don't mean that as a dig at Paleo. I think what we know is the Inuit were free of Western disease. And the !Kung and the Kitivans, etc. We could hope that looking at what these groups have in common--real food, little in the way of refined foods--is enough to make the difference, and go eat at a Kitivan/!Kung/Inuit buffet. But would we be right? Weston Price wrote about various groups with slightly different strategies to achieve the same nutritional ends.
Oatmeal has been shown in some studies to be capable of causing a mineral deficiency and increase in cavities, Stephan Guyunet posted on this years ago, I think it was the Mellanby's doing the experiments. Vitamin D was capable of fixing this. Or replacing grains with potato, then the phytic acid wasn't there to chelate the minerals. One group Price wrote about was the Gaels, they ate primarily oats as their carbohydrate source--but their diet was rich in both minerals and fat-soluble vitamins from a high intake of seafood. Who knows? A diet of oatmeal and seafood might be safe, a diet of primarily beef (being close to groups we know of that ate mostly buffalo or elk, in nutrition) might be safe--but take the beef from one safe diet, and the oatmeal from the other safe diet--and the idea that "what out ancestors ate" was safe might
not be safe in this new combination. The beef could have just barely enough mineral content, and the phytic acid from the oatmeal tip a person into a deficiency. (I'm not saying this would happen, just pretending it does to make a long, belaboured point). Paleo people didn't live on "paleo principles," they had long-developed food cultures. A people that didn't wouldn't thrive, long term.