Can You Take calcium and iron Together?
Evidence-based clinical pharmacological assessment, adverse synergy evaluation, and administration separation protocols.
Co-administering calcium and iron has documented pharmacodynamic or pharmacokinetic antagonism capable of triggering acute clinical harm. Do not combine without explicit specialist oversight.
Clinical Mechanism & Evidence Details
Inhibits intestinal CYP3A4-mediated first-pass metabolism, elevating systemic drug concentrations and increasing toxic adverse effect risks.
Alcohol may enhance gastrointestinal irritation, trigger orthostatic hypotension, or alter drug absorption kinetics.
Tannins, polyphenols, and calcium form unabsorbable iron complexes, dropping non-heme iron absorption by 60-80%.
Oxalic acid binds free calcium into insoluble calcium oxalate, rendering it unabsorbable and increasing kidney stone burden.
Calcium competes for enterocyte Divalent Metal Transporter 1 (DMT-1), significantly attenuating non-heme iron and zinc absorption.
Clinical Guidance: Take calcium supplements with meals, but separate from iron and zinc supplements by at least 2 to 3 hours.
Taking other supplements, foods, or medications with this pair?
Add your morning coffee, daily multivitamins, prescription pills, and dinner foods into our instant browser-based radar to check for multi-way chain reactions.
Clinical mechanism and interaction severity derived from openFDA Drug Structured Product Labeling (Section 7), NIH Office of Dietary Supplements (ODS), and NIH NCCIH clinical botanicals database.