Beriberi and Wernicke-Korsakoff syndrome are associated with deficiency of which vitamin?

• A. Vitamin B1
• B. Vitamin B2
• C. Vitamin B3
• D. Vitamin B9

Answer: (A)

Beriberi and Wernicke-Korsakoff syndrome come from a deficiency of thiamine, which is vitamin B1. Thiamine is a coenzyme for enzymes that drive glucose metabolism in the brain, such as pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase, and it helps in the pentose phosphate pathway too. When thiamine is lacking, brain cells can’t efficiently produce energy from glucose, leading to neuronal injury and the symptoms seen in these conditions.

Beriberi can present as dry form with peripheral neuropathy and muscle weakness, or wet form with cardiac symptoms like edema and heart failure. Wernicke-Korsakoff syndrome centers on the brain and produces oculomotor abnormalities, ataxia, confusion, and memory problems that can progress if not treated. This classic pair of conditions is specifically linked to thiamine deficiency, often in contexts of poor nutrition or chronic alcohol use.

Other B vitamins cause different problems—for example, riboflavin deficiency affects the mouth and eyes, niacin deficiency causes pellagra (dermatitis, diarrhea, dementia), and folate deficiency leads to megaloblastic anemia and, in pregnancy, neural tube defects—so they don’t produce the same beriberi and Wernicke-Korsakoff picture.