La vitamine B1 : la première vitamine identifiée

Abstract

B1 vitamin, or thiamin, is a water-soluble vitamin of dietary origin. It acts as a co-factor of metabolic reactions and is involved in the neurotransmission phenomena. The body has a limited stockpile of thiamine, about 25-30 mg, which is found mainly in the liver, but also in the heart, kidneys and muscles. Thiamine is found in many foods (wheat, raw ham, nuts…), and the deficiency is exceptional in industrialized countries where the diet is varied. Absorption defect due to gastric surgery, excessive elimination, chronic alcoholism, pregnancy, elderly subject, genetic disease, rare lack of intake (anorexia). Clinical manifestations of vitamin B1 deficiency or “beriberi” are varied in adults. Gayet-Wernicke’s encephalopathy is an acute neuropsychiatric complication whose progression to Korsakoff syndrome (disorientation, anterograde amnesia and polyneuritis) is irreversible in the absence of treatment. No B1 vitamin overload has been evidenced. B1 vitamin status can be objectively assessed by the determination of transcetolasic activity and/or the determination of thiamine and its intra-erythrocytic phosphoric esters using enzyme and chromatographic techniques. The daily intake required was established in France in 2001 on the basis of sex and age and is approximately 1.1 mg. If a thiamine deficiency is highlighted, a B1 vitamin supplementation will be put in place.