Gut microbiota modulation with long-chain corn bran arabinoxylan in overweight individuals is linked to individualized temporal increase in fecal propionate

Abstract

Variability in the health effects of dietary fibers (DFs) might arise from inter-individual differences in the microbiome’s ability to ferment these substrates into beneficial metabolites. However, our understanding of what drives this individuality is vastly incomplete. Here, we report results from a parallel-arm, randomized controlled trial aimed to characterize the effects of a long-chain, complex arabinoxylan (AX) isolated from corn bran on gut microbiota composition and short-chain fatty acid (SCFA) production as compared to microcrystalline cellulose (non-fermentable control). AX resulted in a global shift in the fecal bacterial community and the promotion of specific taxa, including OTUs related to Bifidobacterium longum, Blautia obeum, and Prevotella copri. AX further increased fecal propionate concentration (overall effect p=0.015, Friedman’s test), an effect that showed two distinct temporal responses that allowed grouping of participants. The two groups showed significant differences in compositional shifts of the microbiome (p≤0.025, PERMANOVA), and multiple linear regression analyses revealed that the propionate response was predictable through shifts, and to a lesser degree, baseline composition of the microbiota. Pre-treatment dietary history was unable to predict the response. This study showed that individualized metabolic effects of DF on the gut microbiota are linked to both compositional shifts and its baseline composition, providing preliminary evidence that such responses might be predictable.