Thiamine (vitamin B1) is a key component of critical enzyme complexes in intermediary metabolism, specifically involving pyruvate decarboxylase, α-ketoglutarate dehydrogenase, and branched-chain α-ketoacid dehydrogenase. Thiamine deficiency may cause Wernicke's encephalopathy or Wernicke–Korsakoff syndrome primarily in adults with chronic alcoholism. Children become deficient from neoplasms, anorexia nervosa, hemodialysis, and certain inherited metabolic disorders.