Vitamin b12

Vitamin B12, also called cobalamin, belongs to the vitamin B complex and is the only water-soluble vitamin that the body can store for several years. Vitamin B12 is essential for the formation of red blood cells, the function of the nervous system and the regeneration of the mucous membranes.

Vitamin B12 is released in the stomach from dietary protein through the action of gastric acid and is preferentially bound to haptocorrin. In the upper small intestine, the haptocorrin-vitamin B12 complex is broken down and vitamin B12 is bound to the intrinsic factor (IF). This IF-vitamin B12 complex can be bound to the enterorocytes via a membrane-bound receptor and absorbed by the cells. In the enterocytes this complex is broken down again, the vitamin B12 is transferred to a third protein, transcobalamin (TC). This complex, known as holotranscobalamin (HoloTC), is transported through the bloodstream and can be absorbed and processed in all cells via a specific receptor.

The daily requirement is about 5ug.

The biological half-life of vitamin B12 is up to 2 years.

Standard value: The standard value in serum is between 150 and 800 pmol/l

Pathologically elevated: vegan diet, intestinal malabsorption, achlorohydrics, lack of intrinsic factor