A patient who had subtotal gastrectomy needs lifelong replacement of which substance?

• A. A water-soluble vitamin
• B. Medium-chain triglycerides
• C. Gastric enzymes
• D. Hydrolyzed protein

Answer: (A)

The key idea is that the stomach is the source of intrinsic factor, a protein essential for absorbing vitamin B12, a water-soluble vitamin. After a subtotal gastrectomy, fewer parietal cells produce intrinsic factor, so B12 cannot be efficiently absorbed in the terminal ileum. Over time this leads to B12 deficiency and related problems, requiring lifelong replacement of this vitamin, typically by injections or high‑dose oral therapy. Other choices don’t fit as well: fats like medium‑chain triglycerides aren’t critically dependent on gastric function for lifelong replacement, and gastric enzymes or hydrolyzed protein aren’t required to be replaced long-term after a partial gastrectomy.