Elucidating the role of the gut microbiota in the physiological effects of dietary fiber
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,
Dan Knights,
Catherine J. Field,
David Berry,
Carla M. Prado,
Jens Walter
Affiliations
Edward C. Deehan
Department of Agricultural, Food and Nutritional Science, University of Alberta
Zhengxiao Zhang
Department of Medicine, University of Alberta
Alessandra Riva
Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna
Anissa M. Armet
Department of Agricultural, Food and Nutritional Science, University of Alberta
Maria Elisa Perez-Muñoz
Department of Agricultural, Food and Nutritional Science, University of Alberta
Nguyen K. Nguyen
Department of Agricultural, Food and Nutritional Science, University of Alberta
Jacqueline A. Krysa
Department of Agricultural, Food and Nutritional Science, University of Alberta
Benjamin Seethaler
Institute of Nutritional Medicine, University of Hohenheim
Yuan-Yuan Zhao
Department of Agricultural, Food and Nutritional Science, University of Alberta
Janis Cole
Department of Agricultural, Food and Nutritional Science, University of Alberta
Fuyong Li
Department of Agricultural, Food and Nutritional Science, University of Alberta
Bela Hausmann
Joint Microbiome Facility of the Medical University of Vienna and University of Vienna
Andreas Spittler
Core Facility Flow Cytometry and Department of Surgery, Research Lab, Medical University of Vienna
Julie-Anne Nazare
Centre de Recherche en Nutrition Humaine Rhône-Alpes, Univ-Lyon, CarMeN Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Hospices Civils de Lyon, F-CRIN/FORCE Network
Nathalie M. Delzenne
Metabolism and Nutrition Research Group, Louvain Drug Research Institute, Université Catholique de Louvain
Jonathan M. Curtis
Department of Agricultural, Food and Nutritional Science, University of Alberta
Wendy V. Wismer
Department of Agricultural, Food and Nutritional Science, University of Alberta
Spencer D. Proctor
Department of Agricultural, Food and Nutritional Science, University of Alberta
Jeffrey A. Bakal
Patient Health Outcomes Research and Clinical Effectiveness Unit, Division of General Internal Medicine, University of Alberta
Stephan C. Bischoff
Institute of Nutritional Medicine, University of Hohenheim
Dan Knights
Department of Computer Science and Engineering, University of Minnesota
Catherine J. Field
Department of Agricultural, Food and Nutritional Science, University of Alberta
David Berry
Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna
Carla M. Prado
Department of Agricultural, Food and Nutritional Science, University of Alberta
Jens Walter
Department of Agricultural, Food and Nutritional Science, University of Alberta
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
