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Calcium and Iron can interact. In single-meal studies 300-600 mg calcium reduced iron absorption by 50-60%. Long-term studies of raised calcium intake show no change in iron status, so this is an acute absorption effect that matters most for people treating iron deficiency. While treating iron deficiency, take iron at a different time of day from calcium supplements. A gap of about 2 hours is a practical schedule, not an interval tested in studies.
In single-meal studies 300-600 mg calcium reduced iron absorption by 50-60%. Long-term studies of raised calcium intake show no change in iron status, so this is an acute absorption effect that matters most for people treating iron deficiency.
Calcium inhibits iron absorption when the two are taken at the same meal
What to do: While treating iron deficiency, take iron at a different time of day from calcium supplements. A gap of about 2 hours is a practical schedule, not an interval tested in studies.
Dose matters: >500mg calcium reduces iron absorption by ~50%. Minimal risk: <200mg calcium minimal effect on iron.
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.