signature=aea06af33b46d1cf1e707c3a00e6543f,Metabolic breath signature of 13C-enriched wheat bran con...

摘要：

Introduction Dietary fibers (DF) have been classified mainly according to their physico-chemical and fermentability properties but it remains unclear whether such classification is relevant when addressing their health effects. Indeed, the nature of physiological effects induced by DF, particularly through their interaction with gut microbiota, remains poorly known due to their diversity, to gut microbiota inter-subjects variability and to the lack of validated non-invasive biomarkers to characterize DF-gut microbiota interaction. The aim of this pilot study was 1) to follow the metabolic fate of ¹³C-labeled DF through the assessment of ¹³C-labelled gut-derived metabolites in excreted breath and 2) to evaluate novel non-invasive breath-derived biomarkers of DF-gut microbiota interactions. Materials and methods Six healthy women (29.7 ± 1.7 years old, BMI: 23.2 ± 0.9kg/m², fiber intake: 23 ± 1g/d) consumed in research settings a controlled breakfast containing eight ¹³C-labelled wheat bran biscuits (50 g of labelled wheat bran, 3.0At%¹³C). ¹³C-labelled wheat bran was obtained from wheat cultivated under ¹³CO₂ enriched atmosphere. Samples of expired gases were collected during 24 h after ingestion in order to measure H₂ and CH₄ by gas chromatography (GC) with piezoelectric detection and ¹³CO₂ and ¹³CH₄ by gas chromatography coupled with an isotope ratio mass spectrometer (GC-IRMS). Apart test breakfast, subjects only consumed standardized meals without fibers. Results The analysis of H₂ and CH₄ 24h-kinetic measurements distinguished 2 groups in terms of fermentation related gas excretion: the high-CH₄ producers with high baseline CH₄ concentrations (42.1 ± 13.7ppm) and low baseline H₂ concentrations (7.3 ± 5.8ppm) and the low-CH₄ producers with low baseline CH₄ concentrations (6.5 ± 3.6ppm) and high baseline H₂ concentrations (20.8 ± 16.0ppm). Following the ¹³C-wheat bran biscuits' ingestion, postprandial H₂ and CH₄ concentrations increased more significantly in the high-CH₄ producer subjects. ¹³C enrichment was detectable in expired gases in all subjects. ¹³CO₂ kinetics were similar for all subjects and correspond to the oxidation of the digestible part of the bran. The appearance of ¹³CH₄ was significantly enhanced and prolonged after 180 min in high-CH₄ producers compared to low-CH₄ producers, suggesting distinct fiber fermentation profile. Discussion This pilot study allowed to consider novel procedures for development of non-invasive breath biomarkers of fiber-gut microbiota interactions. Assessment of expired gas excretion following ¹³C-labelled fiber ingestion allowed deciphering distinct fermentation profiles: high-CH₄ producers vs low-CH₄ producers and accordingly provide a related non-invasive breath metabolic signature of the fiber fermentation for each profile. Further gut microbiota and ¹³C-metabolites analysis will permit to relate the gut bacteria composition with breath gas excretion kinetics according to fiber fermentation profile.

展开