MYTH #2: Vitamin B12 can be obtained from plant sources.

Of all the myths, this is perhaps the most dangerous. While lacto and lacto-ovo vegetarians have sources of vitamin B12 in their diets (from dairy products and eggs), vegans (total vegetarians) do not. Vegans who do not supplement their diet with vitamin B12 will eventually get anemia (a fatal condition) as well as severe nervous and digestive system damage; most, if not all, vegans have impaired B12 metabolism and every study of vegan groups has demonstrated low vitamin B12 concentrations in the majority of individuals. Several studies have been done documenting B12 deficiencies in vegan children, often with dire consequences. Additionally, claims are made in vegan and vegetarian literature that B12 is present in certain algae, tempeh (a fermented soy product) and Brewer's yeast. All of them are false as vitamin B12 is only found in animal foods. Brewer's and nutritional yeasts do not contain B12 naturally; they are always fortified from an outside source.

There is not real B12 in plant sources but B12 analogues--they are similar to true B12, but not exactly the same and because of this they are not bioavailable. It should be noted here that these B12 analogues can impair absorption of true vitamin B12 in the body due to competitive absorption, placing vegans and vegetarians who consume lots of soy, algae, and yeast at a greater risk for a deficiency.

Had Byrnes limited himself to claiming that most B12 in the majority of possible plant sources tested had been found to be inactive analogues, this would be correct. The exceptions identified include undried nori and pleurochrysis carterae (a unicellular alga). The suggestion that soy, algae or yeast increase the risk of B12 deficiency is misleading. Dried nori contains mostly inactive analogues and has been shown to interfere with B12 metabolism if eaten in very large quantities (40 g per day). In normal amounts, however, it causes no problem provided adequate dietary sources of true B12 are consumed. The same applies to fermented soy products and yeasts: there is no indication that their B12 analogues pose any risk to human health. Unfermented soy products such as soy milk and tofu do not contain significant amounts of analogues.

Some vegetarian authorities claim that B12 is produced by certain fermenting bacteria in the lower intestines. This may be true, but it is in a form unusable by the body. B12 requires intrinsic factor from the stomach for proper absorption in the ileum. Since the bacterial product does not have intrinsic factor bound to it, it cannot be absorbed.

Fermenting bacteria in the large intestine certainly do produce B12 (along with plenty of inactive analogues). Many of our primate relatives eat faeces and may obtain much of their B12 from this source.

It is true that Hindu vegans living in certain parts of India do not suffer from vitamin B12 deficiency. This has led some to conclude that plant foods do provide this vitamin. This conclusion, however, is erroneous as many small insects, their feces, eggs, larvae and/or residue, are left on the plant foods these people consume, due to non-use of pesticides and inefficient cleaning methods. This is how these people obtain their vitamin B12. This contention is borne out by the fact that when vegan Indian Hindus later migrated to England, they came down with megaloblastic anaemia within a few years. In England, the food supply is cleaner, and insect residues are completely removed from plant foods.

This is very muddled. There are no studies of B12 status in Indian vegans as veganism is very rare in India. Indian lacto-vegetarians in the UK show a higher incidence of megaloblastic anaemia than typical in the UK, due to relatively low dietary intake of B12. However, the vast majority of Hindu lacto-vegetarians in the UK and in India never develop symptoms of B12 deficiency.

The only reliable and absorbable sources of vitamin B12 are animal products, especially organ meats and eggs (17). Though present in lesser amounts than meat and eggs, dairy products do contain B12. Vegans, therefore, should consider adding dairy products into their diets. If dairy cannot be tolerated, eggs, preferably from free-run hens, are a virtual necessity.

In making this claim, Byrnes is promoting a myth with as little basis as the one he sets out to criticise and with considerable potential for harm. B12 from fortified foods or supplements (directly harvested from bacteria) is at least as reliable and absorbable as B12 from animal products. In setting the US Dietary Reference Intakes for B12, the Institute of Medicine (1998) notes: "Because 10 to 30% of older people may be unable to absorb naturally occurring vitamin B12, it is advisable for those older than 50 years to meet their RDA mainly by consuming foods fortified with vitamin B12 or a vitamin B12-containing supplement." Tucker et al. (2000) present evidence that fortified foods, supplements and dairy products are more effective sources of B12 than meat for all age groups. There is therefore no nutritional reason for vegans to use dairy or eggs as a source of B12 and this attempt to create an illusory need, which conflicts with vegan ethics, is contemptible.

That vitamin B12 can only be obtained from animal foods is one of the strongest arguments against veganism being a "natural" way of human eating. Today, vegans can avoid anemia by taking supplemental vitamins or fortified foods. If those same people had lived just a few decades ago, when these products were unavailable, they would have died.

Having painted a false picture of universal dependence on meat and eggs for B12, Byrnes then draws the conclusion that we are adapted to require animal products in our diet and that vegan diets are unnatural. There is no evidence that humans are biologically adapted to require B12 from animal products, as opposed to any other source of bacteria-generated B12, so the claim that our need for B12 shows that diets free from meat, milk and eggs are "unnatural" does not pass square one. Most large wild primates consume minimal amounts of meat (insufficient to provide a human with B12) yet have blood B12 levels similar to non-vegetarian humans. Some primates eat faeces, some deliberately eat insects and all consume remnants of insects incidentally with the fruits, leaves and shoots which form the bulk of the diet of our great ape relatives. All get their B12 from bacteria.

Modern humans, of all persuasions, embrace the benefits of sanitary food preparation and therefore lose the B12 sources that have sustained our fellow great apes for millions of years. This "unnatural" choice is enthusiastically embraced and creates a need for a different source of bacterial B12 to those satisfying the needs of the other great apes. Fortified foods and supplements containing the desired bacterial B12 provide the perfect alternative: no direct harm to sentient beings, minimal environmental impact and no unhealthy extras such as saturated fat.

The most distinctive characteristic of human nature is our exceptional capacity to recreate our environment in a manner more conducive to our needs. We cook food, live in houses and wear clothes. None of these are "natural" in the sense of having been around for a significant part of human evolution, but all are entirely natural to our species. We manipulate our environment in many ways to meet our needs and, at our best, to avoid harm to other humans, animals and the environment. Getting B12 from fortified foods or supplements is an entirely natural and commendable choice for humans to make.

In this example, Byrnes makes some good points, which have been made previously by many vegetarians and vegans, but he mixes these with inaccurate observations of his own and spins himself to a completely unjustified conclusion. Byrnes claims elsewhere (http://www.mercola.com/2000/apr/2/vegetarian_myths.htm) to have saved two vegans' lives by persuading them to drink milk. This is the sorry end-point of his myth-making "debunking": promoting the demonstrably fallacious myth that only animal products provide reliable and absorbable sources of B12 in order to persuade people to abandon an ethical and at its best exceedingly healthful vegan diet.

For further information on B12, see www.vegansociety.com/html/info/b12sheet.htm or www.veganoutreach.org/health/b12rec.html or http://www.vrg.org/nutrition/b12.htm

For an outline of a talk by Stephen Walsh at the World Vegetarian Congress in July 2002 (B12: an essential part of a healthy plant-based diet) see www.ivu.org/congress/2002/program/stephen-walsh.html

References:

Haddad et al. (1999): American Journal of Clinical Nutrition, 1999; 70: 586S-593S, Dietary intake and biochemical, hematologic, and immune status of vegans compared with nonvegetarians, Ella H Haddad et al.

Institute of Medicine (1998): Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline, National Academy Press, 1998 ISBN 0-309-06554-2 (http://books.nap.edu/books/0309065542/html/306.html)

Tucker et al. (2000): American Journal of Clinical Nutrition, 2000, 71: 514-522, Plasma vitamin B-12 concentrations relate to intake source in the Framingham Offspring Study, Katherine L Tucker et al.

Acknowledgements: My thanks to members of the IVU Science group, particularly Syd Baumel, Jack Norris and Deborah Pageau, for helpful comments on earlier drafts of this critique.

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