Vitamin B-12 is a water soluble vitamin necessary for the maintenance of a healthy nervous system and for the metabolic utilization of fats and proteins. Vitamin B-12 is also essential for the synthesis of DNA during cell division and therefore is especially important for rapidly multiplying cells, such as blood cells. In addition, adequate intake of vitamin B-12, along with folic acid and vitamin B-6, encourages healthy serum homocysteine levels, thereby supporting cardiovascular health. Because vitamin B-12 is found predominantly in animal products, strict vegetarians may benefit from supplementation.