The effect of L-rhamnose on intestinal transit time, short chain fatty acids and appetite regulation: a pilot human study using combined 13CO2/H2 breath tests

Byrne, C. S., Preston, T. , Brignardello, J., Garcia-Perez, I., Holmes, E., Frost, G. and Morrison, D. J. (2018) The effect of L-rhamnose on intestinal transit time, short chain fatty acids and appetite regulation: a pilot human study using combined 13CO2/H2 breath tests. Journal of Breath Research, 12(4), 046006. (doi: 10.1088/1752-7163/aad3f1) (PMID:30015629)

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Background: The appetite-regulating effects of non-digestible carbohydrates (NDC) have in part previously been attributed to their effects on intestinal transit rates as well as microbial production of short chain fatty acids (SCFA). Increased colonic production of the SCFA propionate has been shown to reduce energy intake and stimulate gut hormone secretion acutely in humans. Objective: We investigated the effect of the propiogenic NDC, L-rhamnose, on gastrointestinal transit times using a combined <sup>13</sup>CO<sub>2</sub>/H<sub>2</sub> breath test. We hypothesised that L-rhamnose would increase plasma propionate leading to a reduction in appetite, independent of changes in gastrointestinal transit times. Design: We used a dual <sup>13</sup>C octanoic acid/lactose <sup>13</sup>C-ureide breath test combined with breath H<sub>2</sub> to measure intestinal transit times following the consumption of 25g/d L-rhamnose, compared with inulin and cellulose, in 10 healthy humans in a randomised cross-over pilot study. Gastric emptying (GE) and oro-caecal transit times (OCTT) were derived from the breath <sup>13</sup>C data and compared with breath H<sub>2</sub>. Plasma SCFA and peptide YY (PYY) were also measured alongside subjective measures of appetite. Results: L-rhamnose significantly slowed GE rates (by 19.5min) but there was no difference in OCTT between treatments. However, breath H<sub>2</sub> indicated fermentation of L-rhamnose before it reached the caecum. OCTT was highly correlated with breath H<sub>2</sub> for inulin but not for L-rhamnose or cellulose. L-rhamnose consumption significantly increased plasma propionate and PYY but did not significantly reduce subjective appetite measures. Conclusions: The NDCs tested had a minimal effect on intestinal transit time. Our data suggest that L-rhamnose is partially fermented in the small intestine and that breath H<sub>2</sub> reflects the site of gastrointestinal fermentation and is only a reliable marker of OCTT for certain NDCs (e.g. inulin). Future studies should focus on investigating the appetite-suppressing potential of L-rhamnose and verifying the findings in a larger cohort.

Item Type:Articles
Additional Information:This article presents independent research funded by Imperial College (IC) and supported by the NIHR CRF and BRC at IC Healthcare NHS Trust. The views expressed are those of the author(s) and not necessarily those of IC, the NHS, the NIHR or the Department of Health. The Division of Diabetes, Endocrinology and Metabolism and Investigative Medicine is funded by grants from the MRC, BBSRC, NIHR, an Integrative Mammalian Biology (IMB) Capacity Building Award, an FP7- HEALTH- 2009- 241592 EuroCHIP grant and is supported by the NIHR Biomedical Research Centre Funding Scheme. GF holds an NIHR Senior Investigator Award, CSB was funded by the United Kingdom Medical Research Council (MR/K01711X/1).
Glasgow Author(s) Enlighten ID:Preston, Professor Tom and Morrison, Dr Douglas
Authors: Byrne, C. S., Preston, T., Brignardello, J., Garcia-Perez, I., Holmes, E., Frost, G., and Morrison, D. J.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Journal of Breath Research
Publisher:Institute of Physics Publishing Ltd.
ISSN (Online):1752-7163
Published Online:17 July 2018
Copyright Holders:Copyright © 2018 IOP Publishing
First Published:First published in Journal of Breath Research 12(4):046006
Publisher Policy:Reproduced under a Creative Commons License

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