POSTNATAL ATTAINMENT OF INTRAUTERINE MACROMINERAL ACCRETION RATES IN LOW-BIRTH-WEIGHT INFANTS FED FORTIFIED HUMAN-MILK

Hypothesic: Provision of more bioavailable mineral sources as human mi lk supplements enables very low birth weight (VLBW) infants to meet th e intrauterine accretion rate for calcium and phosphorus. Design: Comp arison of currently formulated human milk fortifier with previous form ulation. Setting: Neonatol level II and III nurseries Patients: Twenty -six healthy, VLBW infants, whose mothers chose to breast-feed. Interv entions: We tested the effects of two formulations designed for VLBW i nfants as human milk supplements and differing primarily in their quan tity and source of Ca, P, and magnesium. The study interval began with a milk intake of 100 ml . kg(-1) . day(-1) and ended when a body weig ht reached 2.0 kg. Main outcome measures: Net absorption and retention of Ca, P, and Mg during a nutritional balance study conducted once du ring the study interval, growth during the entire study interval, and bone mineral content of the radius were measured at the beginning and end of the study interval. Results: The newer Ca gluconate-glycerophos phate preparation (given to group CaGP) resulted in greater net absorp tion and retention of Ca and P (p <0.01) than in infants given Ca phos phate (group CaTB). Mg retention was greater than (in group CaGP) or e quivalent to (in group CaTB) the intrauterine accretion rate. Radius b one mineral content was significantly greater in group CaGP than in gr oup CaTB (p <0.001). Volumes of the fortified human milk preparation n eeded to meet the needs for gain in body weight were higher in group C aGP than in group CaTB (p <0.001). Conclusions: Intrauterine accretion rates for Ca and P can be achieved when VLBW infants are fed human mi lk supplemented with Ca gluconate-glycerophosphate. Supplementation of human milk with Mg may not be indicated. In this study, greater intak es of Ca and P, and not improvements in bioavailability, result in imp roved net retention and bone mineral content of VLBW infants.