Cobalt is widely spread in nature and constitutes about 0.001% of the earth's crust. Although it is an important trace element, in large quantities causes various disorders. In sixties of the last century, some breweries have used cobalt to regulate the froth of beer. For people who have largely been consumed this beer were reported nausea, vomiting, and heart problems (cardiomyopathy), which was initially attributed to drunkenness. Cobalt is often present in the polluted air.

Cobalt is considered as essential trace element in the body and it is a part of the vitamin B₁₂ making its active part. In addition to its role in the vitamin B₁₂ cobalt participate in only a few enzymes, and this is the reason why some authors do not classify it into the essential micronutrients.

Physiological role of cobalt

Cobalt is an essential trace element that is an integral part of vitamin B₁₂, which is essential in the metabolism of folic acid and fatty acids.

Besides cobalt is involved in the production of erythrocytes and is important for the proper functioning of the nervous system as it can help in creating a myelin sheath.

In addition to its role in cobalamin cobalt is a part of some metalloproteinases that in their structure does not contain Corinne (characteristic for the cobalamin which binds cobalt) such as methionine aminopeptidase-II and nytrile hydratase.

Metabolism

Cobalt is absorbed in the digestive tract. In small doses, the cobalt is almost completely absorbed, while in larger doses it is poorly absorbed. Cobalt absorption is affected by the nutritional factors, for example amino acids reduce the absorption and iron deficiency increase it.

Cobalt is mostly accumulated in the liver of man (where are the body stores of vitamin B12). It has about 20% of its total amount in the body.

Cobalt is excreted primarily in the urine, but in smaller quantities in faeces.

Food sources of cobalt

Food sources of cobalt are meat, liver, kidneys, milk, oysters, mussels, fish, shellfish. Smaller amounts of cobalt are found in mushrooms (especially shitake). In fruits and vegetables, usually there are no cobalt (with the exception of legumes, spinach, cabbage, lettuce, turnips, cabbage, figs). This explains why vegetarians often have a deficiency of this mineral.

Recommended daily allowance

Cobalt are assimilated only by intake of vitamin B12, and not in its ionic or metallic form. Therefore, there is no clear recommended amounts of cobalt because there are just recommendations for vitamin B12. In this vitamin it is absorbed in the amount of 5-8 micrograms per day.

If the cobalt enters the body in some other form, then it can be very toxic. Lethal doses of cobalt (LD50) are about 150-500 mg per kilogram of body weight.

Cobalt deficiency

Deficiency disease or symptoms is manifested in vitamin B₁₂ deficiency and the lack of vitamin B₁₂ leads to anaemia. Sufficient intake of vitamin B₁₂ will not be a problem with the cobalt in the body. Vegetarians have to pay special attention to cobalt and vitamin B₁₂ deficiency. Soil is becoming poor with cobalt, which further reduces the already low level of cobalt in plant foods.

Overdose

Cobalt toxicity usually occurs when the cobalt entries the body in its inorganic form. This occurs in cases of food contamination. Even low levels of cobalt exposure seem to hamper lung function. Excess of cobalt in the body leads to the following disorders:

In addition to nickel and chromium cobalt is a major cause of contact Dermatitis; Cardiomyopathy; Nausea; Heart problems: Goiter; Kidney damage; Nerve damage; Overproduction of red blood cells (erythrocytes) - thickened blood

Severe auditory and optic nerve toxicity has also been observed, in patients exposed to an abnormal release of cobalt and chromium from damaged hip prostheses.

Increased activity in the bone marrow

Cobalt in medicine

Haemopoisis: Cobalt is used (as a part of the vitamin B₁₂) in pernicious anaemia by improving blood because it promotes the formation of red blood cells (erythrocytes).

Cobalt must be entered in large quantities (with food or vitamin B12) in vegetarians.

Tonic: Cobalt is added in the cases of fatigue, digestive problems and neuro-muscular problems.

Cancer: Radioactive cobalt (₆₀Co) is used in the treatment of some cancers.

References

Apostoli P., et al., 2013, “High doses of cobalt induce optic and auditory neuropathy,” Experimental and Toxicologic Pathology; 65(6): 719-727. [Web Reference]

Mao X., Wong A.A., and Crawford R.W., 2011, “Cobalt toxicity—an emerging clinical problem in patients with metal-on-metal hip prostheses,” Med J. Aust.; 194(12): 649-51. [Web Reference]

Rehfisch P., et al., 2012, “Lung function and respiratory symptoms in hard metal workers exposed to cobalt,” Journal of Occupational and Environmental Medicine; 54(4): 409-413. [Web Reference]

Simonsen L.O., Harbak H. and Bennekou P., 2012, “Cobalt metabolism and toxicology-a brief update,” Science of the Total Environment; 432: 210-215. [Web Reference]

Soetan K.O., Olaiya C. O. and Oyewole O.E., 2010, “The importance of mineral elements for humans, domestic animals and plants-A review,” African Journal of Food Science; 4(5): 200-222. [Web Reference]

Yamada K., 2013, "Cobalt: its role in health and disease,” Interrelations between Essential Metal Ions and Human Diseases. Springer Netherlands; 295-320. [Web Reference]