title: Partition of nitrogen intake and excretion in low-birth-weight infants.
abstract: Although nitrogen balance studies have been carried out in low-birth-weight infants, few have partitioned the nitrogen into its components. In this study, 72-hour balance studies were conducted in 24 low-birth-weight infants (gestational age, 30.7 +/- 1.6 weeks; birth weight 1.36 +/- 0.25 kg) fed their mothers' milk (preterm milk) or 50% preterm milk and 50% formula. Total nitrogen, nonprotein nitrogen, and whey protein intake and excretion were measured. Total nitrogen intake (preterm milk group, 452 +/- 138 mg/kg per day; preterm + formula group, 406 +/- 93 mg/kg per day), absorption (85%), and retention (71%) were not significantly different between groups. Intact and fragments of secretory IgA and lactoferrin were detected in soluble fecal extracts, and represented 25% and 9% of intake, respectively. Feeding preterm milk allows for nitrogen accretion similar to intrauterine growth rates for 5 weeks postnatally, and provides potentially functional proteins for the low-birth-weight infant.
authors.affiliation: Department of Nutrition, University of California, Davis 95616.
authors.forename: S M
authors.initials: SM
authors.lastname: Donovan
authors.forename: S A
authors.initials: SA
authors.lastname: Atkinson
authors.forename: R K
authors.initials: RK
authors.lastname: Whyte
authors.forename: B
authors.initials: B
authors.lastname: Lönnerdal
mesh_terms: D001724:Birth Weight; D005243:Feces / Q000032:analysis; D005260:Female; D005865:Gestational Age; D006801:Humans; D007225:Infant Food; D007230:Infant, Low Birth Weight / Q000378:metabolism*; D007231:Infant, Newborn; D008297:Male; D008895:Milk, Human / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*
chemical_list: D009584:Nitrogen