As cobalt is found naturally in the environment, and is essential for bacteria and plants, as well as for animals and humans in the form of vitamin B12, cobalt levels in human and animal tissues can never be ‘zero’.
Cobalt is a natural component of the earth’s crust and through natural environmental processes can be found in water, soil and air.
Plants and animals
The cobalt in soil is taken up by certain bacteria in the roots of plants, where it is used by the bacteria to provide macronutrients (i.e. nitrogen-containing compounds) to the plants. These bacteria require cobalt as a trace element, as do some types of algae. The bacteria can then deliver the macronutrients to the plant, which results in the growth and overall health of the plant.
Animals receive cobalt through plants and water (at low levels). Bacteria in the stomach of ruminant animals (animals that chew the cud and have a stomach consisting of four chambers) require cobalt and in turn use cobalt for the synthesis of vitamin B12. This vitamin is essential for healthy livestock, and cobalt deficiency in farm animals, ‘bush sickness’, is cured by adding cobalt to soil fertilisers and animal feed.
Cobalt in humans
Humans ingest cobalt through the drinking of water, as well as the eating of plants and animal products (i.e. dairy products and meat). Cobalt is essential to humans in the form of vitamin B12, which contributes to healthy blood cell formation and neurological health.
Vitamin B12 deficiency is a concern for vegans and vegetarians, as this vitamin is only present in animal-derived foods (eggs, milk products, meats). Deficiency is also an issue for patients who have undergone weight-loss surgery (certain types of gastric bypass operations), or suffer from chronic stomach or intestinal disorders. This is due to a very specific sequence of events that are needed for vitamin B12 absorption.
In the first step of the absorption process, vitamin B12 is bound to a protein called “R protein”, which is secreted in the mouth by salivary glands. R protein forms a complex with vitamin B12, and protects the vitamin from being destroyed in the acidic environment of the stomach. The stomach releases another molecule needed for the absorption process, called intrinsic factor. Intrinsic factor and the R protein-vitamin B12 complex pass independently through the stomach. Once these molecules reach the upper intestine, vitamin B12 is released from its complex with R protein through digestion facilitated by the pancreas, and instead binds to intrinsic factor. The new complex, intrinsic factor-vitamin B12, can be absorbed by the cells lining the intestine, but only in a very specific region of the intestine called the ileum. Here, the complex enters the cells and vitamin B12 is released inside the intestinal cell, which then transports the vitamin on to the blood stream. Vitamin B12 is delivered to the liver for storage and distribution into the body as needed.
A disruption in any of the steps results in malabsorption of vitamin B12. The complexity of the digestion and absorption of this vitamin explains why many different conditions can result in a deficiency, such as weight loss surgery, mild pancreas- or stomach conditions, as well as certain rare deficiencies in the secretion of R protein or intrinsic factor.
Vitamin B12 deficiency symptoms include anaemia, gastrointestinal disturbances and neurological impairment (e.g. weakness, depression or memory loss). Depending on the underlying cause of a vitamin B12 deficiency, it can easily be treated with different methods: Vitamin B12 supplements can be taken in the case of a nutritional deficiency in people who can absorb the vitamin. Deficiency based on malabsorption in patients with any digestive disorder or bypass surgery needs to be treated with vitamin B12 in the form of a nasal spray or an intramuscular injection.