Antacids reduce calcium absorption
Proton pump inhibitors (omeprazole, pantoprazole) and H2 blockers reduce stomach acid needed for calcium absorption. Long-term PPI use linked to increased fracture risk. Calcium citrate absorbs better than carbonate in low-acid environment.
Take calcium separately from antacids. Use calcium citrate if on long-term PPIs.
Take calcium 2 hours before or after antacids
Antacids reduce calcium absorption. Take calcium separately from antacids. Use calcium citrate if on long-term PPIs.
Take calcium 2 hours before or after antacids
This interaction is rated “Info” by Formulate. Proton pump inhibitors (omeprazole, pantoprazole) and H2 blockers reduce stomach acid needed for calcium absorption. Long-term PPI use linked to increased fracture risk. Calcium citrate absorbs better than carbonate in low-acid environment.
Studies from our registry that mention antacids or calcium. Each links to the primary source and the other Formulate pages citing it.
Mentions calcium · 2015
Calcium intake and risk of fracture: systematic review
Bolland et al. · BMJ
Systematic review finding little evidence that increasing calcium intake prevents fractures in community-dwelling adults.
Mentions calcium · 2010
Iron bioavailability and dietary reference values
Hurrell R, Egli I · American Journal of Clinical Nutrition
Reviews enhancers (vitamin C, meat) and inhibitors (phytate, polyphenols, calcium) of non-heme iron absorption, providing the mechanistic basis for pairing iron with vitamin C and separating it from tea/coffee.
Mentions calcium · 2000
Prediction of dietary iron absorption: an algorithm for calculating absorption and bioavailability
Hallberg and Hulthén · American Journal of Clinical Nutrition
Foundational model for non-heme iron absorption factoring vitamin C, phytates, tannins, and calcium interactions.
Other interactions to know
Calcium significantly reduces iron absorption
Long-term antacid use depletes B12
Calcium blocks thyroid medication absorption
High calcium can impair magnesium absorption
Calcium may reduce zinc absorption
Antacids significantly reduce iron absorption
PPIs impair magnesium absorption
PPIs reduce calcium carbonate absorption
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Medical disclaimer. This page is for educational purposes only and does not replace advice from a qualified healthcare provider.
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