Evaluating the effects of intrinsic and isolated arabinoxylans on human gut microbiota and short-chain fatty acids: A systematic review and meta-analysis

Abstract

Background & objective

Dietary fibers can alter the gut microbiota that is linked to the host health, however, the human intervention results showed varying degrees of prebiotic efficacy and the reasons are unclear. This study appraises literature to provide an overview of the complex regulatory mechanisms of intrinsic arabinoxylans-rich foods and isolated arabinoxylans in their interactions with the gut microbiota. The Embase, Scopus, PubMed, and Web of Science databases were searched up to Oct 31, 2023. The GRADE was used to assess evidence quality.

Key findings

A total of 34 human interventional studies involving 1324 participants were included. The isolated arabinoxylans manipulated gut microbiota abundance more selectively than intrinsic arabinoxylans, thereby reducing microbial diversity (SMD: −0.55, 95% CI: −0.94, −0.15) and promoting Bifidobacterium abundance (SMD: 0.32, 95% CI: 0.11, 0.54). The longer-chain arabinoxylans with the high-dose (≥10 g/day) enhanced the production of fecal propionate (SMD: 0.62, 95% CI: 0.04, 1.21), whereas the shorter-chain arabinoxylan-oligosaccharides (≥10 g/day) reduced isobutyrate (SMD: −1.67, 95% CI: −2.34, −1.01) and isovalerate (SMD: −1.29, 95% CI: −1.92, −0.67). The intrinsic arabinoxylans showed greater efficacy in increasing acetate (SMD: 0.51, 95% CI: 0.19, 0.82) and butyrate levels (SMD: 0.34, 95% CI: 0.03, 0.66).

Conclusion

The regulatory effects of arabinoxylans on the gut microbiota, and especially short-chain fatty acids production, depended on their discrete structures, intrinsic properties, and dosages. It highlights a better defining the role of dietary fibers for precise use in manipulations of the human gut microbiota and their metabolic functions relevant to health.