Vitamin B12 is a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is involved in the metabolism of every cell of the body, especially affecting DNA synthesis and regulation, as well as fatty acid synthesis and energy production.
The anti-anaemic virtues of veal liver were discovered in 1925. At the time, an extrinsic dietary factor was identified, which was not isolated until the middle of the century, when it was given the name vitamin B12. It is the only vitamin that incorporates a mineral (cobalt) in its composition.
Vitamin B12 is involved in many essential biochemical reactions as a coenzyme and plays a primary role in the synthesis of proteins and the production of red cells.
Deficiencies in vitamin B12 are rare but may result in poor growth and neuropathies. However, because vitamin B12 is only made by microbes and found in animal tissue, a vegetarian diet may lead to a deficiency.
Microbes can make vitamin B12 for absorption by animals. Milk and meat products contain good sources of vitamin B12.