Supplement with Vitamin B12 Vitamin B12, also called cobalamin, is one of eight Vitamin B12water-soluble B vitamins. Vitamin B12 is a member of the Vitamin B complex. It contains cobalt, and so is also known as cobalamin. It is exclusively synthesized by bacteria and is found primarily in meat, eggs, and dairy. All B vitamins help the body to convert carbohydrates into glucose (sugar), which is "burned" to produce energy. The B vitamins, often referred to as B complex vitamins, are essential in the breakdown of fats and protein. B complex vitamins also play an important role in maintaining muscle tone, lining the digestive tract, and promoting the health of the nervous system, skin, hair, eyes, mouth, and liver.