Long‐Term β‐galacto‐oligosaccharides Supplementation Decreases the Development of Obesity and Insulin Resistance in Mice Fed a Western‐Type Diet

SCOPE: The gut microbiota might critically modify metabolic disease development. Dietary fibers such as galacto‐oligosaccharides (GOS) presumably stimulate bacteria beneficial for metabolic health. This study assesses the impact of GOS on obesity, glucose, and lipid metabolism. METHODS AND RESULTS: Following Western‐type diet feeding (C57BL/6 mice) with or without β‐GOS (7% w/w, 15 weeks), body composition, glucose and insulin tolerance, lipid profiles, fat kinetics and microbiota composition are analyzed. GOS reduces body weight gain (p < 0.01), accumulation of epididymal (p < 0.05), perirenal (p < 0.01) fat, and insulin resistance (p < 0.01). GOS‐fed mice have lower plasma cholesterol (p < 0.05), mainly within low‐density lipoproteins, lower intestinal fat absorption (p < 0.01), more fecal neutral sterol excretion (p < 0.05) and higher intestinal GLP‐1 expression (p < 0.01). Fecal bile acid excretion is lower (p < 0.01) in GOS‐fed mice with significant compositional differences, namely decreased cholic, α‐muricholic, and deoxycholic acid excretion, whereas hyodeoxycholic acid increased. Substantial changes in microbiota composition, conceivably beneficial for metabolic health, occurred upon GOS feeding. CONCLUSION: GOS supplementation to a Western‐type diet improves body weight gain, dyslipidemia, and insulin sensitivity, supporting a therapeutic potential of GOS for individuals at risk of developing metabolic syndrome.