Thiamine deficiency leads to which conditions?

• A. Pellagra
• B. Scurvy
• C. Night blindness
• D. Beriberi and Wernicke-Korsakoff's syndrome

Answer: (D)

Thiamine is a critical cofactor in energy metabolism, essential for enzymes like pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, and transketolase. When thiamine is deficient, cells struggle to produce ATP from glucose, hitting high-demand tissues such as the brain and heart. This energy shortfall manifests as Beriberi, with dry form showing neuropathy and weakness and the wet form causing cardiomyopathy and edema. In the brain, damage to regions like the mammillary bodies leads to Wernicke encephalopathy (the triad of ophthalmoplegia, ataxia, and confusion); if untreated, it can progress to Korsakoff syndrome with prominent memory impairment and confabulation. Thus thiamine deficiency leads to Beriberi and Wernicke-Korsakoff's syndrome.

Pellagra, Scurvy, and Night blindness are due to deficiencies of other vitamins—niacin, vitamin C, and vitamin A, respectively—not thiamine.