Prolonged Gastric Acid Suppression and Vitamin B₁₂ Deficiency

In theory, prolonged suppression of gastric acid production could predispose patients to vitamin B₁₂ deficiency; gastric acidity promotes extraction of B₁₂ from food, allowing it to be absorbed after binding to intrinsic factor. This case-control study from the Kaiser system in California was designed to show whether proton-pump inhibitors (PPIs) and histamine-2–receptor antagonists (H₂RAs) are associated with vitamin B₁₂ deficiency.

Researchers compared 26,000 patients in whom B₁₂ deficiency was diagnosed during a 15-year interval (cases) and 184,000 matched controls without this diagnosis. Cases were significantly more likely to have received ≥2 years of recent PPI therapy than were controls (12.0% vs. 7.2%). The association remained signi…