Fueling Gut Microbes: A Review of the Interaction between Diet, Exercise, and the Gut Microbiota in Athletes

Abstract

The athlete's goal is to optimize their performance. Towards this end, nutrition has been used to improve the health of athletes' brains, bones, muscles, and cardiovascular system. However, recent research suggests that the gut and its resident microbiota may also play a role in athlete health and performance. Therefore, athletes should consider dietary strategies in the context of their potential effects on the gut microbiota, including the impact of sports-centric dietary strategies (e.g., protein supplements, carbohydrate loading) on the gut microbiota as well as the effects of gut-centric dietary strategies (e.g., probiotics, prebiotics) on performance. This review provides an overview of the interaction between diet, exercise, and the gut microbiota, focusing on dietary strategies that may impact both the gut microbiota and athletic performance. Current evidence suggests that the gut microbiota could, in theory, contribute to the effects of dietary intake on athletic performance by influencing microbial metabolite production, gastrointestinal physiology, and immune modulation. Common dietary strategies such as high protein and simple carbohydrate intake, low fiber intake, and food avoidance may adversely impact the gut microbiota and, in turn, performance. Conversely, intake of adequate dietary fiber, a variety of protein sources, and emphasis on unsaturated fats, especially omega-3 (ɷ-3) fatty acids, in addition to consumption of prebiotics, probiotics, and synbiotics, have shown promising results in optimizing athlete health and performance. Ultimately, while this is an emerging and promising area of research, more studies are needed that incorporate, control, and manipulate all 3 of these elements (i.e., diet, exercise, and gut microbiome) to provide recommendations for athletes on how to "fuel their microbes."

Keywords: athletic performance; carbohydrates; gastrointestinal health; microbiome; prebiotics; probiotics; protein.

FIGURE 1

Fueling your microbes for athletic performance. Sport-centric and gut-centric dietary strategies both modulate the composition and function of the gut microbiota, which may then mediate or modulate the effects of these dietary strategies on athletic performance. Human digestive processes produce amino acids and fatty acids from ingested protein and fat, respectively, while nondigestible carbohydrates make it down to the large intestine intact. These components as well as ingested supplements such as probiotics then interact with the gut microbiota, which produces metabolites that influence local gastrointestinal barrier function as well as systemic functions such as glycogen storage, fuel utilization, and muscle function that have the potential to affect athletic performance. BCFA, branched-chain fatty acid; GI, gastrointestinal; FODMAP, fermentable oligo-, di-, monosaccharides and polyols.