Characterization of carbohydrates in commercial infant formulae

Human milk has always been the reference parameter for the preparation of commercial formulae. The advent of more advanced technologies has enabled increasingly precise information on the composition of human milk to be obtained. Our knowledge in the field of carbohydrates also has improved considerably in the last few years following the pioneering studies of Montreuil (1, 2). From a quantitative point of view it has been demonstrated that in the different phases of lactation, in addition to lactose, human milk contains a consistent amount of oligosaccharides (about 20 g/1 in colostrum and 10–13 g/l in mature milk) (3, 4), whereas monosaccharides make up only about 1% of the total carbohydrates (4). More than 100 different types of oligosaccharides have been identified so far in human milk (5–7), mostly tri-octasaccharides (8). From a biochemical point of view, oligosaccharides are constituted by glucose, galactose, N -acetyl-glucosamine, fucose and sialic acid, and present a linear or branching structure (5). Little is known yet about their physiological role or metabolic fate (9); nevertheless, it has been demonstrated that, in addition to their nutritional function, they participate also in the regulation of the intestinal ecosystem, encouraging the growth of bifid flora (10) and contributing to the defense mechanisms against pathogens in various organs (11–13).