In iron-depleted women without anemia, oral iron supplements induce an increase in serum hepcidin (SHep) that persists for 24 hours, decreasing iron absorption from supplements given later on the same or next day. Consequently, iron absorption from supplements is highest if iron is given on alternate days.

Whether this dosing schedule is also beneficial in women with iron-deficiency anemia (IDA) given high-dose iron supplements is uncertain.

The primary objective of this study was to assess whether, in women with IDA, alternate-day administration on same dose iron increases iron absorption compared to consecutive-day iron administration.

Secondary objectives were to correlate iron absorption with SHep and iron status parameters. We performing an interventional study iron absorption in women with IDA (n=60) median hemoglobin 11.5 mg/dL, who received alternate days of ferrous sulfate given at 8 AM on days 2, 4 and 6 untill day 30 labeled with stable iron isotopes 57Fe, 58Fe and 54Fe; after a third-month incorporation period,.

 Iron absorption on consecutive days  and alternate days was assessed by measuring erythrocyte isotope incorporation. For both doses, SHep was higher on alternate days In iron-depleted women, providing iron supplements daily as divided doses increases serum hepcidin and reduces iron absorption.

Providing iron supplements on alternate days and in single doses optimizes iron absorption and might be a preferable dosing regimen. These findings should be confirmed in iron-deficient anaemic patients.