Deficiency of which nutrient is primarily implicated in Wernicke encephalopathy?

• A. Thiamine deficiency
• B. Niacin deficiency
• C. Vitamin C deficiency
• D. Vitamin D deficiency

Answer: (A)

Thiamine deficiency is implicated in Wernicke encephalopathy. Thiamine (vitamin B1) is a crucial cofactor for enzymes that generate energy from carbohydrate metabolism, including pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase. When thiamine is lacking, brain cells struggle to produce enough ATP, especially in areas such as the mammillary bodies and thalamus, leading to the acute neurologic signs of Wernicke—eye movement abnormalities, gait ataxia, and confusion. This condition is especially common in people with chronic alcohol use due to poor intake, malabsorption, and increased metabolic demand, and it requires immediate thiamine administration to prevent progression to irreversible damage or Korsakoff syndrome. Other deficiencies listed cause different conditions—niacin deficiency leads to pellagra with dermatitis, diarrhea, and dementia; vitamin C deficiency causes scurvy; vitamin D deficiency affects bone health—so they are not associated with Wernicke encephalopathy.