Vitamin B12(cobalamin) works with folic acid in many body processes including the synthesis of DNA, red blood cells, and the maintenance of the myelin sheath that surrounds nerve cells. A B12 deficiency results in pernicious anemia, impaired nerve function, and impaired mental function. Folic acid is one of the most essential nutrients for all normal cell growth and replication. Folic acid has major role in DNA synthesis and without it cells do not divide properly. The benefit of folic acid (along with B12) supplementation is a result of reducing body concentrations of homocysteine. Homocysteine has a hand in a variety conditions, including atherosclerosis, multiple sclerosis, osteoporosis, and mental decline to name a few. Folic acid deficiency is linked to depression, atherosclerosis, and birth defects. Folic acid supplementation should always include B12 because folic acid can hide an underlying B12 deficiency, which can result in permanent nerve damage.
