Which vitamin supplementation is essential for life if ileum completely removed?

• A. Vitamin C supplementation
• B. Vitamin K supplementation
• C. Vitamin A supplementation
• D. Vitamin B12 supplementation for life

Answer: (D)

Vitamin B12 absorption depends on intrinsic factor from the stomach and uptake in the terminal ileum. When the ileum is completely removed, that absorption step is lost, so the body cannot acquire B12 from food. Because the liver stores a large amount of B12 and these stores can last years, deficiency may take time to develop, but once it does it can cause dangerous anemia and nerve damage. To prevent these outcomes, lifelong B12 replacement is required, typically via injections or, in some cases, high-dose oral B12 that is absorbed passively. Other vitamins (like C, A, and K) do not rely on the ileum in the same critical way, so they do not necessitate lifelong supplementation solely due to ileal removal.