Maternal Hepcidin Is Associated with Placental Transfer of Iron Derived from Dietary Heme and Nonheme Sources

The determinants of placental transport of dietary iron remain largely uncharacterized. The objective of this research was to elucidate determinants of fetal Fe transfer from maternally ingested dietary heme and non-heme Fe. The study was undertaken in 19 pregnant females (16–32 y) who ingested intrinsically labeled 58Fe-heme and a nonheme Fe source (57FeSO4) during the third trimester of pregnancy. At delivery, maternal and cord blood was obtained to assess neonatal 57Fe and 58Fe enrichment as a function of maternal/neonatal Fe status [serum ferritin (SF), transferrin receptor, hemoglobin (Hb), total body Fe, and hepcidin]. There was a greater percentage of maternally absorbed 58Fe tracer present in the neonates compared to the 57Fe tracer (5.4 ± 2.4 vs. 4.0 ± 1.6; P < 0.0001). Net dietary nonheme Fe (mg) and heme Fe (mg) transferred to the fetus were both inversely correlated with measures of maternal serum hepcidin (P = 0.002, r2 = 0.43; P = 0.004, r2 = 0.39) and SF (P = 0.0008, r2 = 0.49; P = 0.003, r2 = 0.41) and directly associated with neonatal Hb (P = 0.004, r2 = 0.39; P = 0.008, r2 = 0.35). The results of this study suggest that during pregnancy there appears to be preferential fetal use of maternally ingested Fe derived from a dietary, animal-based heme source compared to Fe ingested as ferrous sulfate. Maternal serum hepcidin and maternal/neonatal Fe status may play a role in placental uptake of dietary heme and nonheme Fe.