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

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)

The main concept is that gastric acid is needed to release vitamin B12 from protein in food, and suppressing acid with a proton pump inhibitor can impair that release. When B12 remains bound to dietary proteins, it can’t pair with intrinsic factor, which is essential for absorption in the ileum. By lowering stomach acidity, PPIs reduce the amount of B12 freed from food, leading to less intrinsic factor–B12 complex formation and decreased absorption over time. Because body stores of B12 can last for years, the deficiency risk tends to rise with longer-term use, often after several years of continued acid suppression. This aligns with the statement that PPIs decrease gastric acidity and may interfere with absorption of protein-bound dietary B12, with deficiency more likely after long-term use.

The main concept is that gastric acid is needed to release vitamin B12 from protein in food, and suppressing acid with a proton pump inhibitor can impair that release. When B12 remains bound to dietary proteins, it can’t pair with intrinsic factor, which is essential for absorption in the ileum. By lowering stomach acidity, PPIs reduce the amount of B12 freed from food, leading to less intrinsic factor–B12 complex formation and decreased absorption over time. Because body stores of B12 can last for years, the deficiency risk tends to rise with longer-term use, often after several years of continued acid suppression. This aligns with the statement that PPIs decrease gastric acidity and may interfere with absorption of protein-bound dietary B12, with deficiency more likely after long-term use.