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

Abstract

Abstract: The concentrations of the six major sialyl oligosaccharides found in the milk of 24 Japanese women were determined using reverse phase high performance liquid chromatography of the 3-methyl-1-phenyl-5- pyrazolone derivatives of the oligosaccharides. The milk was collected at 4, 10, 30 and 100 days postpartum. The concentrations of all six oligosaccharides decreased during the course of lactation. The concentrations of 6'-sialyllactose, sialyllacto-N-tetraose b and disialyllacto-N-tetraose decreased only after 10 days postpartum, whereas those of sialyllacto-N-tetraose a and sialyllacto-N-neotetraose c as well as 3'-sialyllactose decreased from 4 days postpartum. Large differences were observed between present data and those previously reported for Italian women, both in terms of the content and in the variation pattern of each oligosaccharide during the course of lactation. These differences may be caused by the different ethnicity of the donors as well as the assay methods used in the studies.