Abstract
A significant fraction of the carbohydrates in our diet cannot be broken down by our own digestive enzymes. For simplicity, these ‘non-digestible carbohydrates’ are here referred to simply as ‘fibre’. This diet-derived fibre passes through the stomach and small intestine to reach the large intestine, where it becomes the major energy source for the resident microbiota. Most of the fibre that we eat is fermentable, meaning that it can be broken down by our gut microbiota under the anaerobic conditions that prevail in the large intestine. On the other hand, some fibre is non-fermentable and behaves simply as a ‘bulking agent’, passing right through the gut un-degraded. In addition, carbohydrates produced by our own cells can be accessed by gut micro-organisms as energy sources.
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Notes
- 1.
‘FODMAPS ’ stands for ‘Fermentable oligosaccharides, disaccharides, monosaccharides and polyols’. This is in fact somewhat broader than the current definition of soluble fibre as it includes molecules such as lactose that have fewer than three sugar residues.
- 2.
Previously there was a tendency to distinguish between resistant starches and non-starch plant fibre , with the term fibre limited to ‘non-starch polysaccharides (NSP)’ such as cellulose , xylans, pectins and inulin . This has now been largely abandoned, with resistant starch being regarded as a fibre .
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Flint, H.J. (2020). How Gut Micro-organisms Make Use of Available Carbohydrates. In: Why Gut Microbes Matter. Fascinating Life Sciences. Springer, Cham. https://doi.org/10.1007/978-3-030-43246-1_7
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DOI: https://doi.org/10.1007/978-3-030-43246-1_7
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