Location: Obesity and Metabolism ResearchTitle: Does exercise alter gut microbial composition? A systematic review
|MITCHELL, CASSIE - Virginia Tech|
|DAVY, BRENDA - Virginia Tech|
|HULVER, MATTHEW - Virginia Tech|
|NEILSON, ANDREW - Virginia Tech|
|DAVY, KEVIN - Virginia Tech|
Submitted to: Medicine and Science in Sports and Exercise
Publication Type: Review Article
Publication Acceptance Date: 8/14/2018
Publication Date: 1/1/2019
Citation: Mitchell, C.M., Davy, B.M., Hulver, M.W., Neilson, A.P., Bennett, B.J., Davy, K.P. 2019. Does exercise alter gut microbial composition? A systematic review. Medicine and Science in Sports and Exercise. 51(1):160-167. https://doi.org/10.1249/MSS.0000000000001760.
Interpretive Summary: Chronic diseases are largely preventable by adoption of healthy lifestyle behaviors, such as regular physical activity (PA) and healthy dietary intake patterns. In contrast, sedentary behaviors, physical inactivity, and consumption of a western diet (e.g. high-fat, high-sugar) have been associated with aging and the development chronic diseases. Exercise and PA confer a wide range of health benefits, such as improved cardiorespiratory fitness, lower body mass index (BMI), and lower risk for chronic disease. Many mechanisms by which consumption of a western diet contribute to disease development and progression have been identified, including the dysbiosis of the gut microbiome. However, little information is available on other lifestyle behaviors (e.g. exercise and PA) that may shape the gut microbial composition. To date, there have been no systematic reviews evaluating the independent effects exercise and/or PA on the gut microbiome composition, although multiple narrative reviews have been written on the independent effects of exercise on the gut microbiome. Therefore, the objectives of this systematic review were to identify research articles that evaluated the effect of exercise or PA on the gut microbiome, and to summarize translational findings to inform future research.
Technical Abstract: Purpose: The objectives of this systematic review of literature were to evaluate and summarize research in mammals that have investigated the effects of exercise or physical activity (PA) on gut microbial composition. Methods: This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Databases for this review included: PubMed; PubMed Central; Medline; Cumulative Index of Nursing and Allied Health Literature (CINAHL); Web of Science; Commonwealth Agricultural Bureaux (CAB) Direct; Health Source: Nursing Academic Edition; Clinicaltrials.gov; PROSPERO; and The Cochrane Library. Results: Database searches yielded 85 articles. Of those, 25 met inclusion criteria: 17 rodent, 1 canine, 2 equine, and 5 human investigations. All rodent and equine studies included control groups; whereas, only one human study included a control group. Remaining investigations were cross-sectional or longitudinal. All rodent investigations controlled for dietary intake, and one human investigation implemented 3-d dietary control measures. Thirteen studies utilized forced exercise, and 11 assessed voluntary or habitual exercise or PA patterns. Diversification within the Firmicutes phylum was consistently observed in exercise groups across studies. There were no consistent trends within Bacteroidetes, Actinobacteria, or Proteobacteria. The potential interactions between dietary composition and exercise and their respective influences on the intestinal microbiome were not well characterized. Conclusion: Exercise appeared to influence gut microbiome composition in rodent models independent of diet, and was associated with an increased butyrate-producing bacteria in the gut microbiome of humans. Overall quality of evidence in humans was low, and risk of bias was unclear. Future investigations should standardize reporting outcomes and control for diet, exercise duration, mode, and intensity, to further determine the relationship between exercise, gut microbiome composition, and health.