Kobalamina – właściwości biomedyczne i niedobór w ujęciu biochemicznym

Cobalamin (vitamin B₁₂) is a water-soluble organic compound that belongs to the B group of vitamins. Because of the complex structure and polarity of vitamin Bmolecule, its proper use and transformation in the human organism require the participation of specialized proteins. The main source of cobalamin for humans is food of animal origin. Due to tissue cobalamin reserves, the symptoms of its deficiency occur after several years of insufficient food supply. However, screening for cobalamin deficiency is reasonable in people with hypocobalaminemia risk factors such as gastric or small intestinal resection, vegan diet, long-term use of metformin, histamine H2-receptor antagonists, and proton pump inhibitors, as well as old age.

Vitamin B₁₂ as an enzyme cofactor participates in numerous intra-mitochondrial reactions and in the synthesis of methionine, which is necessary for the formation of S-adenosylmethionine, an important factor in the process of methylation of biological molecules. Through metabolic links with folic acid, cobalamin affects DNA synthesis and cell division. Currently, more and more attention is paid to the potential contribution of vitamin B₁₂ deficiency in the pathogenesis of neurodegenerative diseases and cancers. At the molecular level, cobalamin deficiency leads to the destabilization of cellular genome, which increases the risk of malignant transformation. On the other hand, in people with cancer or at high risk of developing it, vitamin B₁₂ may increase the expansion of neoplastic cells.