Vitamin B12 is a water-soluble vitamin that is necessary for maintaining nerve cells, red blood cells and producing DNA. Vitamin B12 is often used by the body in combination with other B vitamins as well.Vitamin B12 can be found bound to the protein in meats, seafood and dairy products. Because of this, many vegetarians and vegans often suffer from vitamin B12 deficiency. When meat is consumed, the hydrochloric acid that is located in the stomach releases vitamin B12 from the protein. Once the vitamin is released, it combines with another substance called the intrinsic factor before absorbed into the blood stream.