Vitamin B12 Revisited
By Allan R. Handysides and Peter N. Landless
I’m a researcher and have focused on vitamin B12. In the World Health column in the August 2012 issue of Adventist World, you suggested that lacto-ovo vegetarians might fare better than those eating a total plant-based diet. I recently surveyed the literature, and it’s my finding that all vegetarians are likely to be deficient in vitamin B12. Would you comment?
We have contacted researchers studying some 95,000 North American Adventists, including total plant-based dietary groups, lacto-ovo vegetarians, omnivores, and groups in between (the Adventist Health Study II). You are correct in suggesting that vitamin B12 is of concern to all vegetarians—and maybe more so to those living where much of the food is not fortified.
Vitamin B12 is a water-soluble vitamin that’s important in facilitating the function of folic acid. It’s also needed for blood formation and nervous tissue function. It’s found naturally only in animal-sourced foods, and consequently its sufficiency is of importance to all vegetarians. Symptoms of deficiency are late in onset.
The group of Adventists in the Adventist Health Study do not at first appear to show significant numbers with vitamin B12 deficiency, perhaps because of conscious attention to utilizing vitamin B12-fortified foods or specific B12 supplements. The findings reported to us of vitamin B12 levels in the Adventist Health Study are preliminary and should not be construed as definitive. There remains a need for vigilance among all vegetarians and even some who occasionally eat meat.
There’s a condition called pernicious anemia, in which an individual lacks what’s called the “intrinsic factor.” This leads to a malabsorption of vitamin B12. Persons with pernicious anemia usually require injectable vitamin B12 of 1,000 micrograms a month, or a daily dissolvable tablet that absorbs in the mouth.
A recent article in the Canadian Medical Association Journal reported on vitamin B12 deficiency in two infants.1These infants were breastfed; one the child of a vegan mother, and the other of a mother with pernicious anemia. When a mother herself has low B12 levels, her breast milk will contain inadequate B12 levels as well. These infants became anemic and suffered neurologic developmental failure. They displayed symptoms of lethargy, low muscle tone, apathy, and general weakness. Imaging studies showed brain atrophy. Whether they will fully recover remains to be seen. This appears to indicate that all vegetarians—perhaps everyone—should be aware of the need for vitamin B12.
One of our major concerns is the use of “homemade” or unfortified soy drinks as substitutes for cow’s milk. These products do not contain the required fortification of vitamin B12. It’s important to check the nutrition content of all such substitutes for animal products to be sure they contain supplemental vitamin B12. If they don’t, we recommend that such vegetarians take supplemental vitamin B12.
We are especially concerned that vegan breastfeeding mothers should have supplemental vitamin B12, and that their infants receive careful pediatric surveillance for its deficiency. Brain or nerve damage secondary to B12 deficiency is often irreversible. The recommended minimum intake of 2.5 micrograms a day should be viewed as such: a minimum level.
The Canadian Medical Association Journal article (referencing several studies) reported one in 20 women of childbearing age in Canada has inadequate levels of vitamin B12.2 The Canadian Health Measures Survey found about 5 percent of women aged 20 to 45 years old were deficient, and 20 percent had marginal stores.
On a global scale, vitamin B12 deficiency is a significantly greater risk on the subcontinent of India and in Mexico, Central America, and certain regions of Africa.
There are significant health advantages of a vegetarian diet. So far, neither the Adventist Health Study nor any other scientifically valid study permits selection of one or another variety of vegetarian diet as being definitely superior to the others, but it’s clear that all vegetarians should be aware of vitamin B12 requirements.
1 Nadia Ronmeliotis, David Dix, and Alisa Lipson, in Canadian Medical Association Journal 184, no. 14 (Oct. 2, 2012).
Allan R. Handysides, a board-certified gynecologist,
is director of the General Conference Health Ministries Department.
Peter N. Landless, a board-certified nuclear cardiologist,
is associate director of the General Conference Health Ministries Department.