Description
Thiamine (Vitamin B1) is a water-soluble vitamin that is produced by plants and microorganisms.
Vitamin B1 is found free, peptide bound and as phosphoesters (mono-, di- and triphospho-esters). It is primarily found in foods and also in supplements. The intake of thiamine in the gut is maintained by active transport and passive diffusion. The different phosphoesters are synthesized by phosphorylation and dephosphorylation. The active form in metabolism is thiamine pyrophosphate and thiamine triphosphate in the brain. After dephosphorylation, thiamine is secreted by the kidney.
Thiamine pyrophosphate plays an important role as a coenzyme in carbohydrate and amino acid metabolism. An important reaction is the oxidative carboxylation. Thiamine itself is required for stimulating nerve cells. Thiamine also stimulates the fatty acid- and cholesterol-synthesis in nervous tissues. Severe vitamin B1 deficiency may lead to beriberi, which is characterised by nerve, heart, and brain abnormalities.
