High dose of prebiotics reduces fecal water cytotoxicity in healthy subjects

Mol Nutr Food Res. 2014 Nov;58(11):2206-18. doi: 10.1002/mnfr.201400298. Epub 2014 Oct 17.


Scope: In vitro and animal studies have shown differential colonic fermentation of structurally different prebiotics. We evaluated the impact of two structurally different prebiotics (wheat bran extract (WBE, containing arabinoxylan-oligosaccharides) and oligofructose) on colonic fermentation and markers of bowel health in healthy volunteers.

Methods and results: Nineteen healthy subjects completed a double-blind, cross-over randomized controlled trial. Interventions with WBE, oligofructose or placebo for 2 wk (week 1: 15 g/day; week 2: 30 g/day) were separated by 2-wk wash-out periods. At the end of each study period, colonic fermentation was characterized through a metabolomics approach. Fecal water genotoxicity and cytotoxicity were determined using the comet and WST-1 assay, respectively, as parameters of gut health. Cluster analysis revealed differences in effects of WBE and oligofructose on colonic fermentation. WBE, but not oligofructose, reduced fecal p-cresol (p = 0.009) and isovaleric acid concentrations (p = 0.022), markers of protein fermentation. Fecal water cytotoxicity was significantly lower after intake of WBE (p = 0.015). Both WBE- and oligofructose-intake tended to reduce fecal water genotoxicity compared to placebo (WBE: p = 0.060; oligofructose: p = 0.057). Changes in fermentation were not related to changes in fecal water toxicity.

Conclusion: Structurally different prebiotics affect colonic fermentation and gut health in a different way.

Keywords: Arabinoxylan-oligosaccharides; Fecal water toxicity; Fermentation; Oligofructose.

Publication types

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

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Body Water / chemistry*
  • Colon / metabolism
  • Comet Assay
  • Cross-Over Studies
  • DNA Damage
  • Double-Blind Method
  • Feces / chemistry*
  • Feces / microbiology*
  • Female
  • Fermentation
  • Follow-Up Studies
  • Healthy Volunteers
  • Humans
  • Male
  • Middle Aged
  • Oligosaccharides / administration & dosage
  • Prebiotics*
  • Xylans / administration & dosage
  • Young Adult


  • Oligosaccharides
  • Prebiotics
  • Xylans
  • oligofructose
  • arabinoxylan