Category: Natural chemicals
Introduction and description
Cobalt is a chemical element with symbol Co. Like nickel, cobalt in the Earth's crust is found only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.
It comprises 0.0029% of the Earth's crust and though the element is of medium abundance, natural compounds of cobalt are numerous. Small amounts of cobalt compounds are found in most rocks, soil, plants, and animals.
Cobalt is the active centre of coenzymes called cobalamins, the most common example of which is Vitamin B12. As such it is an essential trace dietary mineral for all animals. Cobalt in inorganic form is also an active nutrient for bacteria, algae and fungi. Vitamin B12 is the only vitamin to contain a metal atom.
Although far less common than other metalloproteins (e.g. those of zinc and iron), cobaltoproteins are known aside from B12. These proteins include methionine aminopeptidase 2 an enzyme that occurs in humans and other mammals which does not use the corrin ring of B12, but binds cobalt directly.
Illnesses and disease of cobalt imbalance
It is possible to suffer from a deficiency of cobalt and from overdose – see Cobalt imbalance.
We get our cobalt principally fom Vitamin B12. But, neither fungi, plants, nor animals are capable of producing Vitamin B12. Only bacteria and archaea have the enzymes required for its synthesis, although many foods are a natural source of B12 because of bacterial symbiosis.
Bacteria in the guts of ruminant animals, for example, convert cobalt salts into vitamin B12.
We do not have the bacteria necessary to use cobalt directly, thus we have to obtain our intake of cobalt via Vitamin B12 found mostly in animals [offal and red meat in particular], fish and shellfish, poultry, milk and dairy products. More details are provided in the section on Vitamin B12. It should be apparent that being a vegetarian or vegan poses some challenges here and Vitamin B12 is an essential vitamin, just as cobalt is an essential trace mineral.
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