It is needed by the body to form healthy blood and perform a variety of other functions. It helps to keep homocysteine in check. It is involved in the production of myelin (a fatty substance found in the sheath that covers our nerves). Deficiency of B12 causes anemia, weakness, pale skin, and psychological disturbances.
Highest: Lamb, and beef kidneys; and lamb, beef, calf, and pork livers. Good sources: beef, herring, and mackerel. Egg yolk, milk, cheese, clams, sardines, salmon, crabmeat, and oysters also have reasonable amount.
No known toxicity.