NutriStack
Calcium and Lansoprazole, a caution.
Lansoprazole reduces absorption of calcium carbonate, which depends on stomach acid for dissolution. Long-term PPI use is associated with a modest but consistent rise in hip and spine fracture risk in large epidemiologic studies. Postmenopausal women and chronic steroid users are at greatest risk.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Calcium and Lansoprazole
- Pair type
- Caution
- Evidence (highest tier)
- Strong
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Strong evidence
Caution
What is happening. Lansoprazole reduces absorption of calcium carbonate, which depends on stomach acid for dissolution. Long-term PPI use is associated with a modest but consistent rise in hip and spine fracture risk in large epidemiologic studies. Postmenopausal women and chronic steroid users are at greatest risk.
Mechanism. Calcium carbonate must be ionized by gastric acid to Ca2+ before duodenal absorption; lansoprazole-induced hypochlorhydria reduces this dissolution. Calcium citrate bypasses the acid-dependent step.
Recommendation. If you take lansoprazole long-term and need calcium, choose calcium citrate, which absorbs well without gastric acid. If using calcium carbonate, take it with food. Ensure adequate vitamin D and discuss bone density monitoring with your prescriber.
Sources (2)
- Yang YX, Lewis JD, Epstein S, Metz DC. Long-term proton pump inhibitor therapy and risk of hip fracture. JAMA. 2006;296(24):2947-53. PMID 17190895
- Zhou B, Huang Y, Li H, Sun W, Liu J. Proton-pump inhibitors and risk of fractures: an update meta-analysis. Osteoporos Int. 2016;27(1):339-47. PMID 26462494
Stack Score
How this pair moves the number.
Effect on the composite score
If both Calcium and Lansoprazole are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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