Relative abundance of the Prevotella genus within the human gut microbiota of elderly volunteers determines the inter-individual responses to dietary supplementation with wheat bran arabinoxylan-oligosaccharides

Abstract

Background The human colon is colonised by a dense microbial community whose species composition and metabolism are linked to health and disease. The main energy sources for colonic bacteria are dietary polysaccharides and oligosaccharides. These play a major role in modulating gut microbial composition and metabolism, which in turn can impact on health outcomes. Results We investigated the influence of wheat bran arabinoxylan oligosaccharides (AXOS) and maltodextrin supplements in modulating the composition of the colonic microbiota and metabolites in healthy adults over the age of 60. Male and female volunteers, (n = 21, mean BMI 25.2 ± 0.7 kg/m2) participated in the double-blind, cross over supplement study. Faecal samples were collected for analysis of microbiota, short chain fatty acids levels and calprotectin. Blood samples were collected to measure glucose, cholesterol and triglycerides levels. There was no change in these markers nor in calprotectin levels in response to the supplements. Both supplements were well-tolerated by the volunteers. Microbiota analysis across the whole volunteer cohort revealed a significant increase in the proportional abundance of faecal Bifidobacterium species (P ≤ 0.01) in response to AXOS, but not maltodextrin, supplementation. There was considerable inter-individual variation in the other bacterial taxa that responded, with a clear stratification of volunteers as either Prevotella-plus (n = 8; > 0.1% proportional abundance) or Prevotella-minus (n = 13; ≤0.1% proportional abundance) subjects founded on baseline sample profiles. There was a significant increase in the proportional abundance of both faecal Bifidobacterium (P ≤ 0.01) and Prevotella species (P ≤ 0.01) in Prevotella-plus volunteers during AXOS supplementation, while Prevotella and Bacteroides relative abundances showed an inverse relationship. Proportional abundance of 26 OTUs, including bifidobacteria and Anaerostipes hadrus, differed significantly between baseline samples of Prevotella-plus compared to Prevotella-minus individuals. Conclusions The wheat bran AXOS supplementation was bifidogenic and resulted in changes in human gut microbiota composition that depended on the initial microbiota profile, specifically the presence or absence of Prevotella spp. as a major component of the microbiota. Our data therefore suggest that initial profiling of individuals through gut microbiota analysis should be considered important when contemplating nutritional interventions that rely on prebiotics. Trial registration Clinical trial registration number: NCT02693782. Registered 29 February 2016 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02693782?term=NCT02693782&rank=1

In vitro Colon Fermentation of Soluble Arabinoxylan Is Modified Through Milling and Extrusion

“…This can be the result of cross-feeding reactions between bifidobacteria- and butyrate-producing WBAX responding to Faecalibacterium and Lachnospiraceae taxa ( 23 , 64 ). In CM 1, WBAX promoted propionate production and the growth of Prevotella , which corresponds with a recent study in healthy elderly that identified the Prevotella genus as a driving factor in microbiota response to wheat bran AX ( 65 ). The bloom of Prevotella also explained the succinate accumulation especially observed in native WBAX in CM 1, as some Prevotella species appear to produce succinate preferentially over propionate ( 66 ).…”

“…Several other in vitro studies with other types of wheat bran or AX extracts observed this individual microbiota response as well ( 26 , 69 , 72 ). In addition, data from human intervention studies often show very individual responses in microbiota change upon AX supplementation ( 24 , 65 ), and their outcome is hard to predict due to the complex cross-feeding and ecological interactions occurring within the microbiota. The current setup is, therefore, a first step in gaining knowledge on the impact of processing-induced changes in soluble AX on fermentation kinetics and affected bacterial taxa but, obviously, there is a need for further investigation and validation with more individual microbiota in vivo .…”

Effect of Different Functional Food Supplements on the Gut Microbiota of Prediabetic Indonesian Individuals during Weight Loss

“…It is well-known and has recently been confirmed that the gut microbiota is highly individual-specific [32]. This interindividual difference may also be the reason why a dietary intervention may show an effect or not [33]. We studied the differences in β-diversity between individuals (Figure 4a) in more detail and, when studying the first two principal coordinate axes, we observed that the differences in β-diversity between the samples were either large (usually the consequence of a single intervention; Figure 4b) or very small (Figure 4c).…”

From taxonomy to metabolic output: what factors define gut microbiome health?

“…For example, Chung et al . 158 recently demonstrated that supplementation with wheat bran arabinoxylan oligosaccharides in healthy adults induced variable microbiome changes dependent on the baseline relative abundance of Prevotella . In a different study, Baxter et al .…”