Cobalt

Cobalt is an element from the group of heavy metals. Its chemical symbol is Co. It has the atomic number Z = 27 in the periodic table of elements. Pure cobalt is very hard and has a silvery appearance. Its name is derived from the word cobold, a kind of mischievous (mountain) spirit. The name comes from the miners of the Middle Ages, who often mistook it for silver because of its silvery appearance or suspected silver in cobalt deposits, but were always wrong. It is the 29th most common element in the earth's crust. It was used to color glass in ancient China and Egypt, as well as by the Romans and Greeks. The discovery of the element cobalt is attributed to the Swedish chemist Georg Brandt (1694-1768) in Stockholm in 1735. In nature, it occurs in a number of ores, such as white nickel pyrite or cobalt pyrite. In its pure form, it only occurs in meteorites that have hit the earth. In the technical industry, cobalt is used as a colorant, for the production of permanent magnets and in metal alloys for particularly corrosion-resistant metals. These are used in turbines, jet and rocket engines, chemical plants and tools such as drills and chisels. The radioactive Co 60 with a gamma energy of around 1 MeV and a half-life of 5.27 years is used in cobalt irradiation facilities in radiotherapy for the irradiation of benign and malignant diseases. However, its importance has greatly diminished in recent years due to the use of linear accelerators. Cobalt is a component of vitamin B12 and is therefore involved in the formation of red blood cells. It is also involved in the activation of a number of enzymes, such as superoxide dismutase. This enzyme breaks down hydrogen peroxide (H2O2) in the cell. It is estimated that the human body contains 1-2 mg. The main storage organs for cobalt are the liver, bone marrow, pancreas, spleen and kidneys.

Main suppliers

Cobalt is present in all foods that contain vitamin B12. Vitamin B12 is found in animal products such as meat, offal such as liver, kidneys and heart, as well as in fish, milk and eggs. It is also found in sauerkraut, which is produced microbially. Plants contain virtually no B12. Vegans, i.e. vegetarians who do not eat meat, milk or eggs, should therefore take a B12 supplement. Due to the close chemical relationship between cobalt and iron, high iron concentrations in the intestine, e.g. when taking iron tablets, can lead to reduced absorption of cobalt.

Deficiency symptoms

Vitamin B12, and therefore also cobalt, can be stored in the liver, so that a deficiency only becomes noticeable after a very long time (approx. 2 to 5 years). Vegans, older people or patients who have had their stomach removed, as well as alcoholics who only eat a one-sided diet, are at risk of vitamin B12 deficiency. This manifests itself in damage to the nervous system, which manifests itself as memory impairment and even dementia, and in certain forms of anemia, i.e. blood count changes. This special form of anemia is a so-called macrocytic anemia, in which the erythrocyte stem cells in the bone marrow divide only slowly due to the vitamin B12 deficiency and too few functional erythrocytes are formed.

Overdose and poisoning

Poisoning with cobalt can occur through inhalation or ingestion of cobalt oxide dust or cobalt compounds. The symptoms of acute cobalt poisoning are nausea, vomiting, colicky abdominal pain and shortness of breath. Prolonged cobalt intake can lead to hypothyroidism, polycythemia and cardiomyopathy. It is also known that cobalt can trigger contact eczema, e.g. as a component of cement or glass. The treatment of acute cobalt poisoning consists of immediate gastric lavage. The effect of chelating agents is not proven. Chelating agents are complex compounds that are able to bind metal ions. Chronic cobalt poisoning is treated symptomatically. An overdose of vitamin B12 (also known as cyanocobalamin) is hardly possible because the substance is water-soluble and is largely excreted in the urine if there is an excess.

Daily requirement

The German Nutrition Society recommends a daily intake of 3 µg of vitamin B12 from the age of 13. This corresponds to a cobalt intake of around 0.3 µg.