title: Nutritional proteins in milk and the protein requirement of normal infants.
abstract: All whey proteins in human milk are not absorbed and thus not nutritionally available. There is evidence that secretory immunoglobulin A (SIgA), lactoferrin, and lysozyme are resistant to proteolytic action, and the major part of these protective proteins is excreted in the infant's stool. An exclusively breast-fed infant would thus have a mean intake of 1.3 g of protein per kilogram of body weight per day during the first month and about 0.9 g/kg/d during the third month. Term infants fed with formulas containing 1.5 g of protein per deciliter show metabolic changes that indicate that the infants receive more protein than they require for growth; these changes are not seen in breast-fed infants or in infants receiving a whey-predominant formula containing only 1.1 g/dL of protein. A reevaluation of protein requirement and intake during infancy is suggested.
mesh_terms: D000818:Animals; D001942:Breast Feeding; D002364:Caseins / Q000032:analysis; D002417:Cattle; D005511:Food Handling; D006801:Humans; D007223:Infant; D007225:Infant Food / Q000032:analysis; D007768:Lactalbumin / Q000032:analysis; D007781:Lactoferrin / Q000032:analysis; D008892:Milk / Q000032:analysis; D008894:Milk Proteins / Q000032:analysis; D008895:Milk, Human / Q000032:analysis; D009751:Nutritional Requirements; D009753:Nutritive Value
chemical_list: D002364:Caseins; D008894:Milk Proteins; D007768:Lactalbumin; D007781:Lactoferrin