Cobalt; Most of the Cobalt in the body exists with vitamin B12 stores in the liver. Only one enzyme has an established specific requirement for cobalt. Blood plasma contains approximately 1 mcg of cobalt per 100 mL.

Functions

The well­known essential role of cobalt is as a component of vitamin B12 (cobalamin). This vitamin is essential for the maturation of red blood cells and the normal function of all cells.

Dietary Reference Intakes

The dietary requirement for cobalt is expressed in terms of vitamin B12. Approximately 2 to 3 mcg of vitamin B12 is needed daily.

Food Sources and Intakes

Cobalt exists in foods; however, only microorganisms are able to synthesize vitamin B12. The microorganisms of monogastric species such as humans have an extremel limited capacity for synthesis; therefore humans must obtain vitamin B12—and thus cobalt—from animal foods such as organ and muscle meats.

Deficiency

A cobalt deficiency develops only in relation to a vitamin B12 deficiency. Insufficient vitamin B12 causes a macrocytic anemia. A genetic defect limiting vitamin B12 absorption results in pernicious anemia, which is treated appropriately with massive doses of the vitamin.

Toxicity
A high intake of inorganic cobalt (existing freely from cobalamin) in animal diets produces polycythemia (an overproduction of red blood cells), hyperplasia of bone marrow, reticulocytosis, and increased blood volume.