Cobalt is considered an essential mineral and is an integral part of vitamin B12, or cobalamin. Vitamin B12 and cobalt are so closely connected that the two terms can be used interchangeably.
Cobalt activates a number of enzymes in the body. It is necessary for normal functioning and maintenance of red blood cells as well as all other body cells.
The body does not have the ability to synthesize cobalt and must depend on animal sources for an adequate supply of this nutrient. For this reason, strict vegetarians are more susceptible to cobalt deficiency than are meat eaters. The best sources are meats, especially liver and kidney, oysters, clams, and milk. Cobalt is present in ocean and sea vegetation but is lacking in almost all land green foods, although cobalt-enriched soil can yield minute amounts.
Cobalt is not easily assimilated, and most of it passes through the intestinal tract unabsorbed. Most of what is absorbed is excreted in the urine after being used by the body. Cobalt is stored in the red blood cells and plasma; some storage occurs also in the liver, kidneys, pancreas, and spleen.
There is no Recommended Dietary Allowance for cobalt because the dietary need for it is low and can be supplied in protein foods. The average daily intake of cobalt is 5 to 8 micrograms.
There is evidence that high intakes of cobalt may result in an enlarged thyroid gland. Reduction in the cobalt intake should allow an enlarged thyroid to return to normal size.
In animal tests, excessive cobalt results in too many blood cells, a condition called polycythemia. Less severe symptoms include paleness, fatigue, diarrhea, heart palpitations, and numbness in fingers and toes. It has been found that high-quality protein in the diet helps to protect against the toxic effects of cobalt.
Deficiency Effects and Symptoms
A deficiency of cobalt may be resonsible for the symptoms of pernicious anemia and a slow rate of growth. If cobalt deficiency is not treated, permanent nervous disorders may result.
Beneficial Effect on Ailments
Therapeutic doses of cobalt have been beneficial in the treatment of pernicious anemia. This action is attributed to cobalt's importance as a builder of the red blood cells.