Oral iron supplements increase hepcidin and decrease iron absorption from daily or twice-daily doses in iron-depleted...

Area of Science:

• Nutritional Science
• Human Physiology
• Pharmacokinetics

Background:

• Iron supplements acutely elevate hepcidin levels in the body.
• The duration, dose-dependency, and impact of this hepcidin increase on subsequent iron absorption require further characterization in humans.
• Optimizing oral iron dosing schedules could improve treatment efficacy.

Purpose of the Study:

• To investigate how acute iron-induced hepcidin increases affect iron absorption from successive daily and twice-daily oral iron doses.
• To determine the dose-response relationship of iron supplementation on hepcidin levels and iron absorption.
• To inform optimal oral iron dosing strategies.

Main Methods:

• Recruited 54 nonanemic young women with low ferritin levels (≤20 µg/L).
• Conducted dose-finding studies using labeled ferrous sulfate (FeSO4) at doses ranging from 40 to 240 mg on consecutive days.
• Administered three 60-mg Fe doses within 24 hours in a twice-daily dosing study.

Main Results:

• Doses ≥60 mg significantly increased serum hepcidin and decreased fractional iron absorption by 35-45% within 24 hours.
• Fractional iron absorption decreased with increasing dose, while absolute absorption increased, showing diminishing returns.
• Total iron absorbed from three doses in 24 hours was not significantly greater than from two morning doses.

Conclusions:

• Providing lower iron dosages (40-80 mg) and avoiding twice-daily dosing maximizes fractional iron absorption.
• The sustained hepcidin response suggests that alternate-day iron supplementation may be a viable strategy.
• Further research is needed to evaluate the long-term effects of these optimized dosing schedules on iron status.