Effects of Arabinoxylan and Resistant Starch on Intestinal Microbiota and Short-Chain Fatty Acids in Subjects with Metabolic Syndrome: A Randomised Crossover Study

Abstract

Recently, the intestinal microbiota has been emphasised as an important contributor to the development of metabolic syndrome. Dietary fibre may exert beneficial effects through modulation of the intestinal microbiota and metabolic end products. We investigated the effects of a diet enriched with two different dietary fibres, arabinoxylan and resistant starch type 2, on the gut microbiome and faecal short-chain fatty acids. Nineteen adults with metabolic syndrome completed this randomised crossover study with two 4-week interventions of a diet enriched with arabinoxylan and resistant starch and a low-fibre Western-style diet. Faecal samples were collected before and at the end of the interventions for fermentative end-product analysis and 16S ribosomal RNA bacterial gene amplification for identification of bacterial taxa. Faecal carbohydrate residues were used to verify compliance. The diet enriched with arabinoxylan and resistant starch resulted in significant reductions in the total species diversity of the faecal-associated intestinal microbiota but also increased the heterogeneity of bacterial communities both between and within subjects. The proportion of Bifidobacterium was increased by arabinoxylan and resistant starch consumption (P<0.001), whereas the proportions of certain bacterial genera associated with dysbiotic intestinal communities were reduced. Furthermore, the total short-chain fatty acids (P<0.01), acetate (P<0.01) and butyrate concentrations (P<0.01) were higher by the end of the diet enriched with arabinoxylan and resistant starch compared with those resulting from the Western-style diet. The concentrations of isobutyrate (P = 0.05) and isovalerate (P = 0.03) decreased in response to the arabinoxylan and resistant starch enriched diet, indicating reduced protein fermentation. In conclusion, arabinoxylan and resistant starch intake changes the microbiome and short-chain fatty acid compositions, with potential beneficial effects on colonic health and metabolic syndrome.Trial RegistrationClinicalTrials.gov NCT01618526

Microbiota, metabolome, and immune alterations in obese mice fed a high‐fat diet containing type 2 resistant starch

“…Moreover, the finding that few intestinal metabolites and host responses were correlated with individual bacterial taxa indicates that there is either a redundancy in metabolic (11 of 14) 1700184 and biosynthetic responses to RS among bacterial species, or alternatively, that there are complex community-level, metabolic interactions in the intestine that are not related to individual, dominant bacterial genera. This outcome is consistent with human studies on fermentable fibers [54,63]. Responses of the gut microbiota to such dietary interventions are likely ultimately dependent on the baseline composition and the redundancy of metabolic pathways in multiple bacterial taxa.…”

“…There was also no change in SCFA receptor and transporter gene expression in the colon and cecum. These results differ from human and pig studies in which increases in intestinal SCFA were found with either RS or prebiotic fiber consumption [14,53,54], but are in agreement with a recent study showing no difference in cecal SCFA levels between HF-RS and control HF fed mice [55]. Although butyrate and propionate are generally regarded as beneficial intestinal metabolites, it should also be noted that obese individuals tend to have elevated intestinal SCFA [56,57].…”

Metagenomic Insights into the Degradation of Resistant Starch by Human Gut Microbiota

“…Higher substrate fluxes via that route are indeed most likely during high doses of RS2, which is supported by the proteomics results (Data Set S5); however, increases in gene abundances are not determinative, as most gut bacteria are equipped with that pathway (21). Pathways for propionate synthesis, namely, the succinate pathway, primarily used by Bacteroides, and the propanediol route (found in specific Firmicutes) (28), did not significantly change, which is supported by previous work that revealed only acetate and butyrate to be elevated upon RS2 treatment (12,22).…”

Functional and health-endorsing properties of wheat and barley cell wall’s non-starch polysaccharides

“…They include: a) water extractable arabinoxylans donate electrons or hydrogen atoms to neutralize dietary-free radicals (implicated in the initiation and/or development of chronic diseases) as they traverse through the gastrointestinal tract; and b) arabinoxylans noncompetitively inhibit intestinal α-glucosidase and glucose transporter thereby attenuating postprandial blood glucose levels. [129,130] Ferulic acid and feruloylated arabinoxylan mono-/oligosaccharides have potential for use in diabetes management. [131] Arabinoxylan added to wheat bread can have beneficial effects on glycemic control in type II diabetes.…”