Glycomacropeptide and α-lactalbumin supplementation of infant formula affects growth and nutritional status in infant rhesus monkeys

Abstract

Advances in dairy technology make it possible to enrich infant formula with specific bovine milk components that may enhance nutrient status. Glycomacropeptide, a carbohydrate-rich casein peptide, may increase absorption of calcium, iron, or zinc. alpha-Lactalbumin, a major breast-milk protein, may contribute to a balanced amino acid pattern and increase calcium and zinc absorption. We determined the effects of glycomacropeptide- and alpha-lactalbumin-supplemented infant formula on growth; trace mineral status; iron, zinc, and calcium absorption; and plasma amino acid, blood urea nitrogen, and plasma insulin concentrations. Infant rhesus monkeys (n = 5 infants per group) were breastfed or fed control or alpha-lactalbumin- or glycomacropeptide-supplemented formula from birth to 4 mo of age. Hematologic measures and growth were assessed monthly. Mineral absorption was measured with radioisotopes and whole body counting. Infants fed glycomacropeptide had higher food intake than did other formula-fed infants. Infants fed glycomacropeptide or control formula had higher hematocrit values than did infants that were breastfed or fed alpha-lactalbumin. Infants fed glycomacropeptide or control formula had higher plasma zinc and zinc absorption than did breastfed infants. Where differences were observed, breastfed infants and infants fed alpha-lactalbumin had similar plasma essential amino acid and insulin profiles, which were different from those of infants fed glycomacropeptide or control formula. Glycomacropeptide- or alpha-lactalbumin-supplemented formula has no adverse effects on nutritional status in infant monkeys. Glycomacropeptide supplementation increases zinc absorption, which may permit the reduction of formula zinc concentrations, and alpha-lactalbumin supplementation promotes a plasma amino acid pattern similar to that of breastfed infant monkeys.