Maternal Hepcidin Is Associated with Placental Transfer of Iron Derived from Dietary Heme and Nonheme Sources1-4

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 ^sup 58^Fe-heme and a nonheme Fe source (^sup 57^FeSO^sub 4^) during the third trimester of pregnancy. At delivery, maternal and cord blood was obtained to assess neonatal ^sup 57^Fe and ^sup 58^Fe 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 ^sup 58^Fe tracer present in the neonates compared to the ^sup 57^Fe 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, r^sup 2^ = 0.43; P = 0.004, r^sup 2^ = 0.39) and SF (P = 0.0008, r^sup 2^ = 0.49; P = 0.003, r^sup 2^ = 0.41) and directly associated with neonatal Hb (P = 0.004, r^sup 2^ = 0.39; P = 0.008, r^sup 2^ = 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. [PUBLICATION ABSTRACT]