Differences in the content of human milk oligosaccharides between foremilk and hind milk

Human milk oligosaccharides (HMOs) are the second largest carbohydrate component and the third largest nutrient after lactose, and their content and composition are related to the genetic characteristics of the mother, lactation period, geography, and other factors. This study examined the differences in fat content, protein composition, and oligosaccharides content between foremilk and hind milk in human milk. The results showed that the fat content of human milk was significantly higher in the hind milk than in the foremilk. However, no significant differences in the composition and content of protein in the fore and hind milk. With respect to oligosaccharides, the total amount of HMOs (based on seven oligosaccharides, lacto-N-neotetraose (LNnT), lacto-N-tetraose (LNT), 2′-fucosyllactose (2′-FL), 3′-fucosyllactose (3′-FL), 3′-galactosyllactose (3′-GL), 3′-sialyllactose (3′-SL), and 6′-sialyllactose (6′-SL) in the hind milk was always higher than in the foremilk in almost all mothers. Similar trend was found in specific oligosaccharide including LNnT, LNT, 2′-FL, 3′-FL, and 3′-GL. On the other hand, sialylated oligosaccharides, 3′-SL, and 6′-SL were quite consistent in foremilk and hind milk.