title: Variability of macronutrient concentrations in human milk.
abstract: Variability observed in the energy, total nitrogen, lactose and fat concentrations of human milk was partitioned among subjects, days and sample duplicates. Highly significant differences were detected between individuals and between days within the individual for all four nutrients (P less than 0.001). Subjects, days and sample duplicate determinations contributed 89, 9 and 2 per cent, respectively, to the variance for energy; 87, 12 and 1 per cent for nitrogen; 75, 21 and 4 per cent for lactose; and 92, 8 and less than 1 per cent for fat. The reliability of mean estimates for a group or for an individual was derived for various combinations of subjects, days and duplicates to provide a tool for planning future studies.
authors.affiliation: USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, TX 77030.
authors.forename: N F
authors.initials: NF
authors.lastname: Butte
authors.forename: C
authors.initials: C
authors.lastname: Garza
authors.forename: E O
authors.initials: EO
authors.lastname: Smith
mesh_terms: D000328:Adult; D004734:Energy Metabolism; D005223:Fats / Q000032:analysis; D005260:Female; D006801:Humans; D007223:Infant; D007785:Lactose / Q000032:analysis; D008297:Male; D008895:Milk, Human / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis
chemical_list: D005223:Fats; D007785:Lactose; D009584:Nitrogen