Vitamin D Newsletter
Liver Consumption and Vitamin A Toxicity
Joe from New Mexico writes:
Dr. Cannell: I am a nutritionist and a member of the Weston A. Price Foundation. You forget that humans no longer consume the liver of all animals and fish as we have throughout history. Second, our ability to convert the beta-carotene from plants into the required animal form of vitamin A has been shown to vary from poor to nonexistent.
Dr. Cannell replies:
There is evidence that later humans, when they learned to bring down large mammals, suffered vitamin A toxicity, probably from the liver they began consuming.
The idea that the human genome evolved eating liver is absurd. By the time humans could hunt large mammals, the genome had already evolved. Humans evolved eating a diet not dissimilar to the Great Apes: vegetables, fruit, roots, and some bugs. As far as us eating all kinds of liver, have you tried polar bear liver lately? Or sled dog liver? One serving can be fatal. There is evidence that later humans, when they learned to bring down large mammals, suffered vitamin A toxicity, probably from the liver they began consuming. Chronic consumption of chicken liver caused vitamin A toxicity in twin girls.
Secondly, the idea that the natural system (our intestinal system that converts carotenoids into vitamin A as we need it) Nature created to regulate vitamin A levels is malfunctioning in almost everyone is simply silly. The studies you are referring to are from developing countries where chronic malabsorption and diarrheal diseases are endemic. Just because an autistic child has "bowel problems," it does not mean he is vitamin A deficient. Also, how many case reports of vitamin A deficiency has anyone found in American vegetarians? Plenty of iron and B12 and vitamin D deficiencies in vegans, but virtually no vitamin A deficiency even though many vegetarians have no preformed vitamin A intake at all, only carotenoids.
Page last edited: 09 August 2010