Stable iron isotopic techniques and plasma hepcidin profiles to optimize iron supplementation regimens

Abstract

BackgroundOral iron supplementation is used to treat iron deficiency, but absorption is often low and correction is variable.ObjectiveDetermine the duration and magnitude of the plasma hepcidin (pHep) response induced by oral iron (Fe) supplements and concomitantly measure bioavailability in healthy iron depleted young women.MethodspHep (measured by C‐ELISA), iron status and inflammation were monitored at regular intervals. On day 1, no supplements were given (control day). On days 2 and 3, subjects received iron supplements containing 40, 60, 80, 160 or 240 mg Fe as FeSO4 as either single or two consecutive daily doses extrinsically labeled with stable iron isotopes. Iron bioavailability was measured by the isotopic enrichment of erythrocytic iron 14 days after administration.ResultsBoth Fe dose (P<0.05) and time of day (P<0.05) were associated with increase in pHep. Compared to control days, pHep was significantly higher at 8h and 24h after administration for 60, 80, 160 and 240 mg (P<0.05) but not for 40 mg Fe. Total Fe absorption from the Fe dose on the second day of administration compared to a single Fe dose on the first day was decreased for all dosages above 40 mg( P<0.01). With twice per day dosing (60 mg Fe) the afternoon dose was less bioavailable (P<0.05).ConclusionIn Fe‐depleted women, consecutive day doses of supplemental Fe at 60 mg or above increase pHep and decrease fractional Fe bioavailability. These new data will help guide optimal dosing regimens.