Galactosyllactoses in the Milk of Japanese Women: Changes in Concentration during the Course of Lactation

Abstract

The concentrations of three galactosyllactoses found in the milk of 24 Japanese women were determined using normal phase high-performance liquid chromatography of the 2-aminopyridyl (PA) derivatives of the oligosaccharides. The milk was collected at 4, 10, 30 and 100 days post partum. The concentration of 6´-galactosyllactose (6´-GL) was maximal at 4 days post partum, and then decreased, whereas the concentrations of 3´- and 4´-galactosyllactose (3´-GL and 4´-GL) did not change during the course of lactation. In human milk, 6´-GL was the main oligosaccharide among these galactosyllactoses at 4 days post partum, in contrast to bovine milk in which 3´-GL has been reported to be predominant. The concentrations of these galactosyllactoses in human milk were much lower than those reported for 2´-fucosyllacose, 3-fucosyllactose, lacto-N-fucopentaose I , II and III, and 3´- and 6´-N-acetylneuraminyllactose.