The athletic gut microbiota

Abstract

The microorganisms in the gastrointestinal tract play a significant role in nutrient uptake, vitamin synthesis, energy harvest, inflammatory modulation, and host immune response, collectively contributing to human health. Important factors such as age, birth method, antibiotic use, and diet have been established as formative factors that shape the gut microbiota. Yet, less described is the role that exercise plays, particularly how associated factors and stressors, such as sport/exercise-specific diet, environment, and their interactions, may influence the gut microbiota. In particular, high-level athletes offer remarkable physiology and metabolism (including muscular strength/power, aerobic capacity, energy expenditure, and heat production) compared to sedentary individuals, and provide unique insight in gut microbiota research. In addition, the gut microbiota with its ability to harvest energy, modulate the immune system, and influence gastrointestinal health, likely plays an important role in athlete health, wellbeing, and sports performance. Therefore, understanding the mechanisms in which the gut microbiota could play in the role of influencing athletic performance is of considerable interest to athletes who work to improve their results in competition as well as reduce recovery time during training. Ultimately this research is expected to extend beyond athletics as understanding optimal fitness has applications for overall health and wellness in larger communities. Therefore, the purpose of this narrative review is to summarize current knowledge of the athletic gut microbiota and the factors that shape it. Exercise, associated dietary factors, and the athletic classification promote a more “health-associated” gut microbiota. Such features include a higher abundance of health-promoting bacterial species, increased microbial diversity, functional metabolic capacity, and microbial-associated metabolites, stimulation of bacterial abundance that can modulate mucosal immunity, and improved gastrointestinal barrier function.

Keywords:

• Athletes
• Gut microbiome
• Microbial ecology
• Gut health
• Sports nutrition
• Sport performance
• Exercise
• Physical activity
• Metagenome
• Short-chain fatty acids

Acknowledgments

The authors would like to thank the participants and researchers who contributed works cited in this paper.

Authors’ contributions

AEM and RJ conceptualized and designed this review. AEM, RJ, KCC, and CMK prepared and compiled the first draft for review and editing. All other co-authors critically evaluated and revised the first draft and articles for inclusion. AEM completed the final draft of the manuscript which was reviewed, edited, and approved by all co-authors. The author(s) read and approved the final manuscript.

Funding

The publication fee was sponsored by Increnovo LLC. The authors received no remuneration for writing and/or reviewing this review.

Availability of data and materials

Not applicable.

Ethics approval

Not applicable.

Consent for publication

Not applicable.

Competing interests

KB, LB, and SDW declare no competing interests. RJ has received grants to evaluate the efficacy and safety of probiotics, serves on scientific advisory boards, and has served as an expert witness, legal and scientific consultant. AEM and KCC are employed by Isagenix, a company selling branded probiotics products. CMK has previously received external funding to conduct research studies involving nutritional supplements and is currently conducting studies involving prebiotics and probiotics. MP has received grants to evaluate the efficacy and safety of probiotics and has served as a scientific consultant. JRT reports no conflicts of interest regarding the material or paper presented. JRT has previously received grants to evaluate the efficacy of various nutritional supplements including probiotics. NPW reports no conflicts of interested regarding the paper presented and has been the recipient of external funding to conduct research on nutritional supplements on the microbiome in athletes. MG reports no conflicts of interest regarding the material or paper presented. MG has previously received external funding to conduct research studies involving nutritional supplements including probiotics. DBP reports no conflicts of interest regarding the material or paper presented, and has received grants to evaluate the effectiveness of probiotic supplementation in athletes. BIC has conducted industry sponsored studies at his university and occasionally serves as a scientific and legal consultant related to exercise and nutrition intervention studies. He also serves on the scientific advisory board of Dymatize (Post Holdings). RBK reports no conflicts of interest related to the material presented in this paper. He has conducted industry sponsored studies at the universities he has been affiliated with and occasionally serves as a scientific and legal consultant related to exercise and nutrition intervention studies. CJW is employed by Jamieson Labs, a company selling branded probiotics products. MPA is employed by Biolab research Srl, performing research & development activities for Probiotical SpA, a leading probiotic supplier. DSK reports he works for a contract research organization that has received funding from the probiotic industry for clinical trials and serves on the Scientific Advisory Board for Dymatize (Post Holdings). JS is a co-founder of Fitbiomics, a company identifying, researching and commercializing new probiotic strains. JAT is employed by the International Probiotic Association and further consults within the probiotic and microbiome industries. PJA reports no conflicts of interest related to the material presented in this paper. He serves on the Scientific Advisory Board for Dymatize (Post Holdings), and Isagenix International LLC and has conducted industry sponsored studies involving nutritional supplements. SMA reports no conflicts of interest related to the material presented in this paper. He serves on the Scientific Advisory Board for Dymatize (Post Holdings) and has conducted industry sponsored studies involving nutritional supplements. JA is the CEO of the International Society of Sports Nutrition and reports no conflicts of interest with the material presented.

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