Vitamin B1 (Thiamine) Deficiency

Excerpt

Thiamine, identified many years ago as the first vitamin and designated vitamin B1, functions as a critical catalyst in energy generation through the decarboxylation of branched-chain amino acids and alpha-ketoacids. This vitamin also acts as a coenzyme for transketolase reactions in the form of thiamine pyrophosphate. An additional, not fully defined role involves the propagation of nerve impulses and the maintenance of the myelin sheath. This water-soluble vitamin occurs naturally in meat, beef, pork, legumes, whole grains, and nuts. In contrast, milled rice and processed grains contain minimal thiamine because manufacturing processes remove much of the vitamin. Certain foods, including tea, coffee, raw fish, and shellfish, contain thiaminases, which function as enzymes that degrade thiamine.

Thiamine deficiency affects the cardiovascular, nervous, and immune systems and commonly manifests as wet beriberi, dry beriberi, or Wernicke-Korsakoff syndrome. Worldwide prevalence remains highest in populations relying on polished rice or milled cereals as staple foods and among individuals with chronic alcohol use disorder. Dry beriberi presents with symmetrical peripheral neuropathy, whereas wet beriberi presents with high-output heart failure. Wernicke-Korsakoff syndrome may involve central nervous system manifestations such as gait abnormalities, altered mental status, and ocular findings. Wernicke encephalopathy represents the most severe acute neurologic manifestation of thiamine deficiency and may progress to Korsakoff syndrome without timely thiamine replacement. Detailed discussion of diagnosis and management appears in the dedicated StatPearls article on Wernicke encephalopathy and Wernicke–Korsakoff syndrome.