Q. I currently follow a strict vegetarian diet and consume no animal products at all. Since vitamin B12 is missing from the vegan diet, I wonder how many micrograms of it I should take. I’ve seen B12 pills of up to 1500 micrograms each in my food co-op, but the daily requirement is just 3 micrograms.
A. Vitamin B12 deficiency is far more common than most people realize. Vegans (who eat no eggs, dairy or other animal products) are frequently lacking in this essential nutrient. Older people and those who take powerful acid-suppressing drugs may also be low.
Symptoms of a deficiency include numbness or tingling in legs and arms, trouble walking, sore tongue, loss of appetite, constipation, memory loss and disorientation. You will need to ask your physician for a blood test (MMA as well as vitamin B12). She should be able to recommend the best B12 dose based on your blood levels.
Because vitamin B12 is not well absorbed from pills, you may need a higher dose than the RDA. One study of older people with B12 deficiency found that daily doses of roughly 600 to 1000 micrograms (0.6 to 1 mg) of vitamin B12 were needed to reverse deficiency (Archives of Internal Medicine, May 23, 2005).
