Vitamin B12: A Simple Solution

The vegan diet, rich in fruits, vegetables, whole grains, and legumes, provides an abundance of vitamins and minerals to meet one’s nutritional needs. However, there is one vitamin, called vitamin B12, which does present a genuine nutritional issue, although one that is easily solved.

Produced by bacteria and other one-celled organisms in the small intestines of animals, vitamin B12 made by humans is not well absorbed and retained. Found mainly in animal products, small amounts may be found in plant products due to bacterial contamination.1,2 However, these plant and fermented foods, such as spirulina, sea vegetables, tempeh, and miso, do not provide an active and reliable source,3 so vitamin B12 must be obtained elsewhere in the diet.

For individuals following a diet free of all animal products, vitamin B12 needs can easily be met by consuming a variety of vegan foods. Fortified breakfast cereals, fortified soymilk, and fortified meat analogues, contain a reliable source of the vitamin.4 Nutritional yeast, such as Red Star Vegetarian Support Formula, is also a reliable source. Be sure to check the Nutrition Facts Label or the ingredient list to ensure you are receiving the active form of vitamin B12, called cobalamin or cyanocobalamin. Nearly all common multivitamins, from Flintstones to One-A-Day to Stress Tabs, also contain B12.

Deficiencies of vitamin B12 are rare due to the efficient storage and recycling of this vitamin in the body.3 But regular intake is still important to meet one’s needs. The recommended dietary allowance in adults is 2 micrograms per day, with increased requirements for women who are pregnant or breastfeeding.5 Ensuring that vitamin B12 needs are met as one ages becomes even more critical as deficiencies are common among the elderly.6,7 Symptoms of deficiency may include fatigue, weakness, tingling in the arms and legs, digestive disturbances, and a sore tongue, and may lead to anemia and more serious disorders of the blood and nervous system.5

Listed below are common sources of vitamin B12 in the vegan diet. Be sure to check nutrition labels as products may vary.

Sources: Pennington JAT. Bowes and Church’s Food Values of Portions Commonly Used. Lippincott, New York, 1998. VMessina V and Messina M. The Vegetarian Way. Crown Trade Paperbacks, New York, 1996.

References
1. Herbert V. Vitamin B-12: plant sources, requirements, and assay. Am J Clin Nutr 1988;48:852-8.
2. Rauma A, Torronen R, Hanninen O, Mykkanen H. Vitamin B-12 status of long-term adherents of a strict uncooked vegan diet (“living food diet”) is compromised. J Nutr 1995;125:2511-5.
3. Position of the American Dietetic Association: vegetarian diets. J Amer Diet Assoc 1997;97(11):1317-21.
4. Smith MV. Development of a quick reference guide to accomodate vegetarianism in diet therapy for multiple disease conditions. Am J Clin Nutr 1988;48:906-9.
5. Food and Nutrition Board. Recommended Dietary Allowances, 10th ed. National Academy Press, Washington, DC: 1989.
6. Lindenbaum J, Rosenberg IH, Wilson PWF, Stabler SP, Allen RH. Prevalence of cobalamin deficiency in the Framingham elderly population. Am J Clin Nutr 1994;60:2-11.
7. Carmel R. Cobalamin, the stomach, and aging. Am J Clin Nutr 1997;66:750-9.