Vitamin B-12 is necessary for the production of energy from fats and proteins and is well known for its critical role in DNA synthesis, as well as in homocysteine metabolism.* Methylcobalamin is the co-enzyme form of vitamin B-12 that has been found to be especially critical in the maintenance of a healthy nervous system.* Dietary sources are almost exclusively of animal origin (meat and dairy) and supplementation with B-12 may be especially important for strict vegetarians.