Proton pump inhibitors can affect vitamin B12 absorption. Which statement accurately describes their effect and the risk with long-term use.

• A. They decrease gastric acidity and may interfere with absorption of protein-bound dietary vitamin B12, with deficiency more likely after long-term use (>3 years).
• B. They increase gastric acidity and enhance absorption of dietary B12.
• C. They have no effect on B12 absorption.
• D. They only affect the absorption of crystalline B12 in supplements.

Answer: (A)