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Iron supplements: heme vs non-heme bioavailability

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By NSW Editorial Team · Reviewed by the NSW Editorial Board · Updated

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Quick answer

Heme iron, from animal sources, is absorbed at approximately 25 percent. Non-heme iron, from plant sources and most supplements, is absorbed at 2 to 20 percent depending on co-factors. Vitamin C taken alongside non-heme iron can increase absorption up to threefold. Calcium and tannins reduce absorption.

Forms compared

FormSourceAbsorption
HemeLiver, beef, fish15 to 35 percent
Ferrous sulfateCommon supplement10 to 15 percent
Ferrous bisglycinateChelated supplement25 to 30 percent
Carbonyl ironSlow-release5 to 10 percent

Dosing

Adult daily recommendations vary by age and sex. Typical replenishment doses (under physician guidance): 30 to 60 mg elemental iron per day.

Citations

FAQ

Educational, not medical. These statements have not been evaluated by the Food and Drug Administration. This content is for educational purposes only and is not a substitute for medical advice from a qualified healthcare provider. Not intended to diagnose, treat, cure, or prevent any disease.