Vitamin D and Proton Pump Inhibitors
Long-term proton pump inhibitors (PPIs) — omeprazole, esomeprazole, pantoprazole, rabeprazole, dexlansoprazole — affect several nutrient-absorption pathways. Vitamin D itself doesn't require gastric acid for absorption. But PPIs impair B12 and calcium absorption, and cumulative use has been associated with modestly increased fracture risk.
Vitamin D absorption on PPIs
Vitamin D is fat-soluble; it depends on bile and pancreatic lipase, not gastric acid. PPIs do not reduce vitamin D absorption. Taking a cholecalciferol supplement on a PPI is fine — with a meal for absorption.
Calcium — carbonate vs citrate
Calcium carbonate (cheapest form) requires stomach acid for dissociation and absorption. PPI users have reduced acid, so carbonate is poorly absorbed. Switch to calcium citrate, which absorbs equally well with or without acid. See our calcium page.
B12 deficiency
PPIs impair release of B12 from food proteins (which requires acid). Long-term PPI users (2+ years) have elevated B12 deficiency risk. Consider B12 supplementation (500-1,000 µg oral cyanocobalamin daily) or periodic screening. See our B12 page.
Fracture risk
Meta-analyses of observational data suggest PPI use for > 1 year associates with modestly elevated hip and vertebral fracture risk (relative risk ~1.2-1.3). The mechanism is likely multi-factorial: reduced calcium absorption, altered bone remodelling, potential effects on osteoclasts. FDA labels have included this warning since 2010. Ensuring vitamin D + calcium adequacy and re-evaluating whether the PPI is still needed at annual reviews is prudent.
When PPIs are still worth it
For patients with erosive esophagitis, Barrett's esophagus, Zollinger- Ellison syndrome, or long-term NSAID users with ulcer risk, PPIs remain strongly indicated. The risk-benefit favours continued PPI use in these settings. For uncomplicated GERD, periodic step-down trials to H₂ blockers or on-demand PPI use are reasonable.
Practical guide for PPI users
- Vitamin D 1,000-2,000 IU/day with meals — standard dosing works fine.
- Calcium citrate 500-1,000 mg/day if supplement needed.
- B12 500-1,000 µg/day if long-term PPI use.
- Annual review of PPI indication — try to step down when possible.
- DEXA screening per usual osteoporosis guidelines.