Metabolic signature of 13C-labeled wheat bran consumption related to gut fermentation in humans: a pilot study

Eur J Nutr. 2023 Sep;62(6):2633-2648. doi: 10.1007/s00394-023-03161-5. Epub 2023 May 24.

Abstract

Purpose: The aim of this pilot study was to analyze concomitantly the kinetics of production of 13C-labeled gut-derived metabolites from 13C-labeled wheat bran in three biological matrices (breath, plasma, stools), in order to assess differential fermentation profiles among subjects.

Methods: Six healthy women consumed a controlled breakfast containing 13C-labeled wheat bran biscuits. H2, CH4 and 13CO2, 13CH4 24 h-concentrations in breath were measured, respectively, by gas chromatography (GC) and GC-isotope ratio mass spectrometry (GC-IRMS). Plasma and fecal concentrations of 13C-short-chain fatty acids (linear SCFAs: acetate, propionate, butyrate, valerate; branched SCFAs: isobutyrate, isovalerate) were quantified using GC-combustion-IRMS. Gut microbiota composition was assessed by16S rRNA gene sequencing analysis.

Results: H2 and CH4 24 h-kinetics distinguished two groups in terms of fermentation-related gas excretion: high-CH4 producers vs low-CH4 producers (fasting concentrations: 45.3 ± 13.6 ppm vs 6.5 ± 3.6 ppm). Expired 13CH4 was enhanced and prolonged in high-CH4 producers compared to low-CH4 producers. The proportion of plasma and stool 13C-butyrate tended to be higher in low-CH4 producers, and inversely for 13C-acetate. Plasma branched SCFAs revealed different kinetics of apparition compared to linear SCFAs.

Conclusion: This pilot study allowed to consider novel procedures for the development of biomarkers revealing dietary fiber-gut microbiota interactions. The non-invasive assessment of exhaled gas following 13C-labeled fibers ingestion enabled to decipher distinct fermentation profiles: high-CH4 producers vs low-CH4 producers. The isotope labeling permits a specific in vivo characterisation of the dietary fiber impact consumption on microbiota metabolite production.

Clinical trial registration: The study has been registered under the number NCT03717311 at ClinicalTrials.gov on October 24, 2018.

Keywords: 13C-labeled dietary fiber; Branched short-chain fatty acids; Gut microbiota; Methane; Short-chain fatty acids; Stable isotopes.

Publication types

  • Clinical Trial

MeSH terms

  • Butyrates / metabolism
  • Dietary Fiber* / metabolism
  • Fatty Acids, Volatile* / metabolism
  • Feces / chemistry
  • Female
  • Fermentation
  • Gas Chromatography-Mass Spectrometry
  • Humans
  • Pilot Projects

Substances

  • Butyrates
  • Dietary Fiber
  • Fatty Acids, Volatile

Associated data

  • ClinicalTrials.gov/NCT03717311