Vitamin B12 is a water-soluble vitamin. It is one of 8 different B vitamins. B12 plays a major role in the functioning of the brain and in the formation of red blood cells. In addition, Vitamin B12 helps regulate cell metabolism, including DNA synthesis, fatty acid metabolism and amino acid metabolism. This affects numerous systems in the body including digestion, absorption of nutrients, respiration, blood circulation, elimination of waste from the body and regulation of body temperature. As you can see, Vitamin B12 is an essential vitamin for the health of your body. If the body does not get enough B12, there can be serious consequences.