Naturally found in foods such as fish, milk and milk products, eggs, meat and poultry. Vitamin B12 is important for good health, necessary for the proper digestion and absorption of foods and for normal metabolism of carbohydrates, and fat.

It helps maintain healthy nerve cells and red blood cells and is needed to make DNA. Vitamin B12 is bound to the protein in food. Hydrochloric acid in the stomach releases B12 from protein during digestion. Unlike other water-soluble nutrients, vitamin B12 is stored in the liver, kidney, and other body tissues.

It can take several years before signs of the deficiency appear due to poor dietary intake. Vitamin B12 functions as a "methyl donor." A methyl donor is a compound that carries and donates methyl groups to other molecules, including cell membrane components and neurotransmitters.

As a methyl donor vitamin B12 is involved in homocysteine metabolism and plays a critical role in proper energy metabolism, immune function, and nerve function. Therefore, vitamin B12 is clearly an added benefit for anyone wanting to lose weight, as without it, metabolism is not at its peak potential.