title: The oligosaccharide composition of human milk: temporal and individual variations in monosaccharide components.
abstract: Oligosaccharides are an important component of human milk, but little is known about variations in their composition. The aim of this study was to determine the temporal and inter-individual variations in carbohydrate composition of human milk during the first 3 months of lactation. Serial milk samples of 10 mothers (eight full-term and two preterm births) were analyzed to determine the concentration of lactose and three monosaccharide components derived from the non-lactose carbohydrate: sialic acid, N-acetylglucosamine, and fucose. In full-term milk, sialic acid and N-acetylglucosamine were found to decrease significantly (p < 0.05) from weeks 1 to 13 postnatally. On average (mean +/- SD), sialic acid decreased by 71% (from 879 +/- 157 to 256 +/- 82 mg/L; p < 0.05) and N-acetylglucosamine by 56% (from 1,459 +/- 282 to 646 +/- 214 mg/L; p < 0.05), while fucose decreased by only 35% (from 660 +/- 192 to 432 +/- 180 mg/L; p > 0.05). On average, lactose concentration increased by 17% over the same period, from 55.4 +/- 4.2 g/L in week 1 to 64.9 +/- 2.3 g/L at 3 months. Preterm milk contained higher concentrations of each component, but temporal changes were similar to those seen in full-term milk. Apart from temporal changes, there were large inter-individual differences in oligosaccharide composition: fucose varied four-fold, sialic acid threefold, and N-acetylglucosamine two-fold among women at the same stage of lactation. The changes observed may simply reflect the aging of the cells responsible for milk secretion, but they are also consistent with a programmed adaptation of the milk composition to the needs of the infant.
authors.affiliation: Department of Biochemistry, University of Sydney, Australia, New South Wales.
authors.forename: J B
authors.initials: JB
authors.lastname: Miller
authors.forename: S
authors.initials: S
authors.lastname: Bull
authors.forename: J
authors.initials: J
authors.lastname: Miller
authors.forename: P
authors.initials: P
authors.lastname: McVeagh
mesh_terms: D000117:Acetylglucosamine / Q000032:analysis*; D000704:Analysis of Variance; D005260:Female; D005643:Fucose / Q000032:analysis*; D006801:Humans; D007785:Lactose / Q000032:analysis*; D008895:Milk, Human / Q000737:chemistry*; D019158:N-Acetylneuraminic Acid; D007752:Obstetric Labor, Premature; D011247:Pregnancy; D012794:Sialic Acids / Q000032:analysis*; D013997:Time Factors
chemical_list: D012794:Sialic Acids; D005643:Fucose; D019158:N-Acetylneuraminic Acid; D007785:Lactose; D000117:Acetylglucosamine