Gastrectomy patients are at risk for deficiency of which vitamin?

• A. B12
• B. Folic acid
• C. Thiamine
• D. B6

Answer: (A)

B12 deficiency is the risk after gastrectomy because intrinsic factor, produced by stomach parietal cells, is essential for absorbing vitamin B12 in the ileum. When part or all of the stomach is removed, intrinsic factor production drops or disappears, so the B12–intrinsic factor complex can’t form and B12 absorption declines over time. The body’s stores of B12 can last several years, but once depleted, patients can develop megaloblastic anemia and neurologic symptoms, making lifelong B12 supplementation often necessary (usually by injections). While other vitamins can be affected by malnutrition, the link between gastrectomy and B12 deficiency is the strongest due to loss of intrinsic factor.