Nutritional Proteins in Milk and the Protein Requirement of Normal Infants

[摘要] 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.

[学科分类] 儿科学