EFFECT OF IRON SUPPLEMENTATION DURING LACTATION ON HUMAN-MILK COMPOSITION

There are no reports of studies specifically designed to test the effe ct of maternal iron supplementation on human milk composition The purp ose of this study was to evaluate the effect of moderate (40 mg Fe/day as FeSO4) iron supplementation of nursing women for 3 months after de livery (non-supplemented n = 14; supplemented n = 14) on levels of iro n, lactoferrin, total iron-ligands, and zinc in milk. Iron supplementa tion did not alter significantly iron and zinc levels in milk and the low iron to lactoferrin ratio was maintained, thus preserving the impo rtant functions of lactoferrin for the infant organism. However, iron supplementation increased total iron ligands in milk as measured by th e fetal iron-binding capacity and increased the proportion of lactofer rin in total protein secreted. Also, lactoferrin levels bended (P = 0. 059) to be higher in milk of the supplemented women. Our results sugge st that the increase in total iron ligands and in the proportion of la ctoferrin in total protein in milk after iron supplementation may be a response of the mammary gland to a higher plasma transferrin saturati on.