Elucidating the role of the gut microbiota in the physiological effects of dietary fiber

Posted on 14.05.2022 - 05:10
Abstract Background Dietary fiber is an integral part of a healthy diet, but questions remain about the mechanisms that underlie effects and the causal contributions of the gut microbiota. Here, we performed a 6-week exploratory trial in adults with excess weight (BMI: 25–35 kg/m2) to compare the effects of a high-dose (females: 25 g/day; males: 35 g/day) supplement of fermentable corn bran arabinoxylan (AX; n = 15) with that of microbiota-non-accessible microcrystalline cellulose (MCC; n = 16). Obesity-related surrogate endpoints and biomarkers of host-microbiome interactions implicated in the pathophysiology of obesity (trimethylamine N-oxide, gut hormones, cytokines, and measures of intestinal barrier integrity) were assessed. We then determined whether clinical outcomes could be predicted by fecal microbiota features or mechanistic biomarkers. Results AX enhanced satiety after a meal and decreased homeostatic model assessment of insulin resistance (HOMA-IR), while MCC reduced tumor necrosis factor-α and fecal calprotectin. Machine learning models determined that effects on satiety could be predicted by fecal bacterial taxa that utilized AX, as identified by bioorthogonal non-canonical amino acid tagging. Reductions in HOMA-IR and calprotectin were associated with shifts in fecal bile acids, but correlations were negative, suggesting that the benefits of fiber may not be mediated by their effects on bile acid pools. Biomarkers of host-microbiome interactions often linked to bacterial metabolites derived from fiber fermentation (short-chain fatty acids) were not affected by AX supplementation when compared to non-accessible MCC. Conclusion This study demonstrates the efficacy of purified dietary fibers when used as supplements and suggests that satietogenic effects of AX may be linked to bacterial taxa that ferment the fiber or utilize breakdown products. Other effects are likely microbiome independent. The findings provide a basis for fiber-type specific therapeutic applications and their personalization. Trial registration Clinicaltrials.gov, NCT02322112 , registered on July 3, 2015. Video Abstract


Deehan, Edward C.; Zhang, Zhengxiao; Riva, Alessandra; Armet, Anissa M.; Perez-Muñoz, Maria Elisa; Nguyen, Nguyen K.; et al. (2022): Elucidating the role of the gut microbiota in the physiological effects of dietary fiber. figshare. Collection. https://doi.org/10.6084/m9.figshare.c.5995839.v1
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Edward C. Deehan
Zhengxiao Zhang
Alessandra Riva
Anissa M. Armet
Maria Elisa Perez-Muñoz
Nguyen K. Nguyen
Jacqueline A. Krysa
Benjamin Seethaler
Yuan-Yuan Zhao
Janis Cole
Fuyong Li
Bela Hausmann
Andreas Spittler
Julie-Anne Nazare
Nathalie M. Delzenne
Jonathan M. Curtis
Wendy V. Wismer
Spencer D. Proctor
Jeffrey A. Bakal
Stephan C. Bischoff
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