Supplementation of Diet With Galacto-oligosaccharides Increases Bifidobacteria, but Not Insulin Sensitivity, in Obese Prediabetic Individuals

Gastroenterology. 2017 Jul;153(1):87-97.e3. doi: 10.1053/j.gastro.2017.03.051. Epub 2017 Apr 8.


Background & aims: The gut microbiota affects host lipid and glucose metabolism, satiety, and chronic low-grade inflammation to contribute to obesity and type 2 diabetes. Fermentation end products, in particular the short-chain fatty acid (SCFA) acetate, are believed to be involved in these processes. We investigated the long-term effects of supplementation with galacto-oligosaccharides (GOS), an acetogenic fiber, on the composition of the human gut microbiota and human metabolism.

Methods: We performed a double-blinded, placebo-controlled, parallel intervention study of 44 overweight or obese (body mass index, 28-40 kg/m2) prediabetic men and women (ages, 45-70 y) from October 2014 through October 2015 in Maastricht, The Netherlands. The participants were assigned randomly to groups who ingested 15 g GOS or isocaloric placebo (maltodextrin) daily with their regular meals for 12 weeks. Before and after this period, we collected data on peripheral and adipose tissue insulin sensitivity, fecal microbiota composition, plasma and fecal SCFA, energy expenditure and substrate oxidation, body composition, and hormonal and inflammatory responses. The primary outcome was the effect of GOS on peripheral insulin sensitivity, measured by the hyperinsulinemic-euglycemic clamp method.

Results: Supplementation of diets with GOS, but not placebo, increased the abundance of Bifidobacterium species in feces by 5-fold (P = .009; q = 0.144). Microbial richness or diversity in fecal samples were not affected. We did not observe any differences in fecal or fasting plasma SCFA concentrations or in systemic concentrations of gut-derived hormones, incretins, lipopolysaccharide-binding protein, or other markers of inflammation. In addition, no significant alterations in peripheral and adipose tissue insulin sensitivity, body composition, and energy and substrate metabolism were found.

Conclusions: Twelve-week supplementation of GOS selectively increased fecal Bifidobacterium species abundance, but this did not produce significant changes in insulin sensitivity or related substrate and energy metabolism in overweight or obese prediabetic men and women. number, NCT02271776.

Keywords: Metabolic Control; Microbial Obesity; Prebiotics; Short-Chain Fatty Acids.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetic Acid / analysis
  • Acute-Phase Proteins
  • Adiposity
  • Aged
  • Bifidobacterium*
  • Blood Glucose / metabolism
  • Body Mass Index
  • Carrier Proteins / blood
  • Cytokines / blood
  • DNA, Bacterial / analysis*
  • Dietary Supplements
  • Double-Blind Method
  • Energy Metabolism
  • Feces / chemistry
  • Feces / microbiology
  • Female
  • Galactose / administration & dosage*
  • Gastrointestinal Microbiome
  • Humans
  • Incretins / blood
  • Insulin / blood
  • Insulin Resistance*
  • Male
  • Membrane Glycoproteins / blood
  • Middle Aged
  • Obesity / complications
  • Obesity / metabolism*
  • Oligosaccharides / administration & dosage*
  • Prediabetic State / complications
  • Prediabetic State / metabolism*


  • Acute-Phase Proteins
  • Blood Glucose
  • Carrier Proteins
  • Cytokines
  • DNA, Bacterial
  • Incretins
  • Insulin
  • Membrane Glycoproteins
  • Oligosaccharides
  • lipopolysaccharide-binding protein
  • Acetic Acid
  • Galactose

Associated data