From the book: Simply Vegan: Quick Vegetarian Meals, by Debra Wasserman and Nutrition Section by Reed Mangels, Ph.D., R.D. Published (1990/1991) by the Vegetarian Resource Group, P.O. Box 1463, Baltimore, MD 21203, (410) 366-VEGE. ISBN 0-931411-05-X

Summary: The requirement for vitamin B12 is very low. Non-animal sources include Nutri-Grain cereal (1.4 ounces supplies the adult RDA) and Red Star T-6635+ nutritional yeast (1-2 teaspoons supplies the adult RDA). It is especially important for pregnant and lactating women, infants, and children to have reliable sources of vitamin B12 in their diets.

Vitamin B12 is needed for cell division and blood formation. Plant foods do not contain vitamin B12 except when they are contaminated by microorganisms. Thus, vegans need to look to other sources to get vitamin B12 in their diet. Although the minimum requirement for vitamin B12 is quite small, 1/1000 of a milligram (1 microgram) a day for adults, a vitamin B12 deficiency is a very serious problem leading ultimately to irreversible nerve damage. Prudent vegans will include sources of vitamin B12 in their diets. However, vitamin B12 deficiency is actually quite rare even among long-term vegans.

Bacteria in the human intestinal tract do make vitamin B12. However, the majority of these bacteria are found in the large intestine. Vitamin B12 does not appear to be absorbed from the large intestine.

Normally, vitamin B12 is secreted into the small intestine along with bile and other secretions and is reabsorbed, but this does not add to the body's vitamin B12 stores. Since small amounts of vitamin B12 are not reabsorbed, it is possible that eventually vitamin B12 stores will be used up. However, we may be quite efficient at re-using vitamin B12 so that deficiency is rare.

Some bacteria in the small intestine apparently produce vitamin B12 which can be absorbed. This is one possible explanation for why so few cases of vitamin B12 deficiency are reported. Perhaps our bacteria are making vitamin B12 for us.

At this time, research is continuing on vitamin B12 requirements. Some researchers have even hypothesized that vegans are more efficient than the general public in absorbing vitamin B12. Certainly for other nutrients, such as iron, absorption is highest on low dietary intakes. However, these are only speculations. We need to look for reliable dietary sources for vitamin B12 until we can determine whether or not other sources can supply adequate vitamin B12.

Although some vegans may get vitamin B12 from inadequate hand washing, this is not a reliable vitamin B12 source. Vegans who previously ate animal-based foods may have vitamin B12 stores that will not be depleted for 20 to 30 years or more. However, long-term vegans, infants, children, and pregnant and lactating women (due to increased needs) should be especially careful to get enough vitamin B12.

Few reliable vegan food sources for vitamin B12 are known. Tempeh, miso, and seaweed often are labeled as having large amounts of vitamin B12. However, these products are not reliable sources of the vitamin because the amount of vitamin B12 present depends on the type of processing the food undergoes. Also, Victor Herbert, a leading authority on vitamin B12 states that the amount on the label cannot be trusted because the current method for measuring vitamin B12 in foods measures both active and inactive forms of vitamin B12. The inactive form (also called analogues) actually interferes with normal vitamin B12 absorption and metabolism. These foods may contain more inactive than active vitamin B12.

The RDA (which includes a safety factor) for adults for vitamin B12 is 2 micrograms daily. Two micrograms of vitamin B12 are provided by 1 teaspoon of Red Star T-6635+ yeast powder or 1-1/2 teaspoons of mini-flake yeast or 2 rounded teaspoons of large-flake yeast. Of course, since vitamin B12 is stored, you could use larger amounts of nutritional yeast less often. A number of the recipes in this book contain nutritional yeast.

Another alternative source of vitamin B12 is fortified cereal. Nutri-Grain cereal does contain vitamin B12 at this time and 1.4 ounces of Nutri-Grain, or a little less than 1 cup, will provide 2 micrograms of vitamin B12. We recommend checking the label of your favorite cereal since manufacturers have been known to stop including vitamin B12. New labeling laws do not require labels to include the actual amount of vitamin B12 in a food. However, added vitamin B12 will be listed under ingredients and you can write to the company inquiring about the amount of vitamin B12 in a serving.

Other sources of vitamin B12 are fortified soy milk (check the label as this is rarely available in the US), vitamin B12 fortified meat analogues (food made from wheat gluten or soybeans to resemble meat, poultry or fish) [Midland Harvest products contain B12.], and vitamin B12 supplements. There are vitamin supplements which do not contain animal products.

Further information on Vitamin B12

Myths and Facts About Vitamin B12 (TVS)

Deutsch - Vitamin B12 Dr. med. habil. Dr. Dr. K. J. Probst (SVV)

Vitamin B12 (VegSocUK)

Vitamin B12 in the Vegan Diet (VRG)

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