Serum hepcidin is significantly associated with iron absorption from food and supplemental sources in healthy young women

Background: Hepcidin is a key regulator of iron homeostasis, but to date no studies have examined the effect of hepcidin on iron absorption in humans. Objective: Our objective was to assess relations between both serum hepcidin and serum prohepcidin with nonheme-iron absorption in the presence and absence of food with the use of dual stable-iron-isotope techniques. Design: The study group included 18 healthy nonpregnant women. Women received in random order a supplemental iron source (7.6 mg FeSO4 providing 0.9 mg Fe-58 as FeSO4) and 6.8 mg 57 Fe ferrous sulfate tracer administered with a nonheme food source [orange-fleshed sweet potato (OFSP): 1.4 mg native Fe]. Iron absorption was determined by analyzing blood samples taken 14 d after dosing with the use of magnetic sector thermal ionization mass spectrometry. Serum hepcidin was assessed by a new competitive serum enzyme-linked immunosorbent assay (ELISA) specific for the refolded, mature 25-amino acid form, and serum prohepcidin was assessed by an ELISA specific for amino acids 28-47 of the hepcidin prohormone. Results: In these women, iron absorption averaged 14.71 +/- 10.7% from the supplemental iron compared with 3.63 +/- 6.5% from the OFSP. Absorption of nonheme iron assessed in the presence (P = 0.038) and absence (P = 0.0296) of food was significantly associated with serum hepcidin but was not significantly related to serum prohepcidin. Conclusion: Serum hepcidin, but not prohepcidin, was inversely associated with iron absorption from supplemental and food-based nonheme-iron sources in iron-replete healthy women. Am J Clin Nutr 2009; 89: 533-8.