In women with iron-deficiency anemia (IDA), oral iron supplements induce an acute increase in serum hepcidin (SHep) that persists for 24 hours, diminishing iron absorption from subsequent doses given on the same or following day. This study aimed to assess whether alternate-day administration of 100 and 200 mg iron increases iron absorption compared to consecutive-day dosing in women with IDA.

The study involved a crossover design, where participants received either 100 or 200 mg iron as ferrous sulfate labeled with stable isotopes for two cycles. Results showed that SHep was significantly higher on day 3 compared to day 2 or day 5 for both doses, and fractional iron absorption (FIA) was 40-50% higher on days 2 and 5 than on day 3. Alternate-day dosing resulted in a higher FIA compared to daily dosing, suggesting a potential benefit in maximizing iron absorption while potentially reducing gastrointestinal side effects. However, further long-term intervention studies are needed to confirm these findings and evaluate clinical outcomes such as changes in hemoglobin levels and iron status parameters.

Reference: Stoffel NU, Zeder C, Brittenham GM, Moretti D, Zimmermann MB. Iron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic women. Haematologica. 2020 May;105(5):1232-1239. doi: 10.3324/haematol.2019.220830. Epub 2019 Aug 14. PMID: 31413088; PMCID: PMC7193469.