Individuals following a vegetarian lifestyle - and particularly vegetarian children in Western societies, should supplement extra Vitamin B12, since it is not available from vegetarian food sources, while those with insufficient stomach acid and intrinsic factor may have to supplement 1,000 mcg - 2,000 mcg of Vitamin B12 on a daily basis, or get regular Vitamin B12 injections to prevent pernicious anemia. This may also require the addition of folic acid, which interacts with Vitamin B12, otherwise a folate deficiency may develop. However, a high intake of Folic Acid and Vitamin B12 has been shown to be a risk factor in the development of some cancers... Full Text