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Metabolic breath signature of 13C-enriched wheat bran consumption related to gut fermentation in humans: a Fiber-TAG study
- Anne-Esther Breyton, Valérie Sauvinet, Laure Meiller, Stéphanie Lambert-Porcheron, Christelle Machon, Anne Mialon, Laurie Vandenberghe, Monique Sothier, Sylvie Normand, Alexandra Meynier, Maud Alligier, Audrey Neyrinck, Martine Laville, Nathalie Delzenne, Sophie Vinoy, Julie-Anne Nazare
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- Journal:
- Proceedings of the Nutrition Society / Volume 79 / Issue OCE2 / 2020
- Published online by Cambridge University Press:
- 10 June 2020, E132
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AbstractIntroduction
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 methodsSix 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.
ResultsThe 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.
DiscussionThis 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.
Effect of postprandial modulation of glucose availability: short- and long-term analysis
- Julie-Anne Nazare, Alexis de Rougemont, Sylvie Normand, Valérie Sauvinet, Monique Sothier, Sophie Vinoy, Michel Désage, Martine Laville
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- Journal:
- British Journal of Nutrition / Volume 103 / Issue 10 / 28 May 2010
- Published online by Cambridge University Press:
- 24 December 2009, pp. 1461-1470
- Print publication:
- 28 May 2010
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Low glycaemic index (LGI) foods have been proposed as potential means to decrease postprandial glucose excursions and thus to improve diabetes management. We modulated glucose availability of cereal products and thus their glycaemic index to study the metabolic effect of LGI foods on daylong glucose control acutely and in the long term following a 5-week GI intervention diet in free-living subjects. In this randomised, parallel trial, two groups of nineteen overweight subjects followed an ad libitum 5-week intervention diet in which usual starch was replaced by either LGI or high GI (HGI) starch. During the exploration days (days 1 and 36), subjects ate their assigned 13C-labelled test breakfast (LGI or HGI), and total and exogenous glucose kinetics (using stable isotopes), postprandial concentrations of glucose, insulin, lipid profile and nutrient oxidation were assessed after the test breakfast and a standardised lunch. At day 1, LGI breakfast significantly decreased post-breakfast glycaemic response with a parallel decrease in exogenous and total glucose appearance (P < 0·05). Post-lunch and post-breakfast glycaemic responses were positively correlated (r 0·79, P < 0·0001). Following the 5-week diet, difference between the groups in terms of glucose kinetics and response was maintained (no significant interaction group × time) but tended to decrease over time for the post-breakfast glycaemic response. Post-lunch and post-breakfast glycaemic responses remained positively correlated (r 0·47, P = 0·004). Modulation of postprandial glucose availability at breakfast decreased plasma exogenous glucose appearance and improved glucose control at the subsequent lunch. After 5 weeks, these effects were maintained in healthy subjects but remained to be confirmed in the longer term.