Thiamin (vitamin B1)

Abstract

7.1 Background Thiamin, as thiamin diphosphate (also known as thiamin pyrophos-phate), serves as a coenzyme for enzymes involved in carbohydrate and amino acid metabolism. There is, therefore, an increased requirement for thiamin in situations where metabolism is heightened, for example, during high muscular activity, pregnancy, and lactation, and also during protracted fever and hyperthyroidism. The classic disease resulting from a gross deficiency of thiamin in humans is beriberi, which manifests as a complicated picture of neuro-logical and cardiovascular disorders. Beriberi is prevalent in Far Eastern populations where unfortified polished rice is the staple diet. In chronic alcoholics, thiamin deficiency resulting from poor nutrition can lead to Wernicke–Korsakoff's encephalopathy, which is characterized by mental confusion and deterioration of nerve function. In addition, decreased liver function in alcoholics impairs the utilization of thiamin. Thiamin is practically nontoxic when administered orally owing to its limited absorption and rapid excretion of excess amounts.