Lactose-Derived Glucolacto-Oligosaccharides Increase Specific Beneficial Bacteria in the Human Gut Microbiome

Abstract

This study was aimed at investigating the hitherto unknown prebiotic effects of glucolacto-oligosaccharides on the overall composition and metabolic activity of the human gut microbiota, focusing on the main component 4-galactosylkojibiose (4-GK) in vitro and a glucolacto-oligosaccharide mixture in a human intervention study. Glucolacto-oligosaccharides were enzymatically synthesized from lactose and sucrose using Liquorilactobacillus satsumensis dextransucrase. In vitro fermentation studies demonstrated selective growth promotion of beneficial bacteria, especially Bifidobacterium, Parabacteroides, Lachnospiraceae, and Faecalibacterium. In a 4-week clinical study, the populations of fecal Bifidobacterium and Faecalibacterium significantly increased after administration of glucolacto-oligosaccharides while reducing levels of iso-butyrate and iso-valerate. The fecal bile acid profiles were altered, and serum total cholesterol levels were lowered after ingestion. Furthermore, glucolacto-oligosaccharides ingestion decreased serum zonulin levels, which indicated an improvement in intestinal barrier function. These findings demonstrate that glucolacto-oligosaccharides exhibit prebiotic properties by modulating gut microbiota composition and metabolism, leading to improved host health.