Isolation of a protein from human milk that enhances zinc absorption in humans

Humans absorb zinc more readily from human milk than from the milk of other species. The basis for this species specificity has not been elucidated. This report describes the isolation of a human milk protein which enhances zinc absorption. The consumption of bovine cow's milk supplemented with the human protein resulted in an elevation in human plasma zinc of 101% compared to a 50% rise following the ingestion of cow's milk alone. The identification of this biologically active protein in human milk establishes in part the basis for the species difference in zinc bioavailability.