DuPont Nutrition, an ingredients supplier for food, pharma, and dietary supplement manufacturers, recently published a review they supported examining the effects of probiotics on athletic performance, as told by a collection of clinical trials examining the mechanisms by which the gut microbiota appears to benefit muscle growth, athletic performance, and positive physiological responses during post-exercise recovery periods.
 
While nutritional habits of athletes are highly research, DuPont suggests that the role that the makeup of their intestinal microbiota is proportionally under-examined. Evidence from pre-clinical trials examining the performances of athletes and non-athletes alike show, however, that a gut-muscle axis exists, and that strain specific solutions could reduce gastrointestinal and respiratory symptoms to help them train and compete at their best.
 
“Our gut bacteria play a key role in our overall health. It’s not surprising, then, that it would also play a role in determining our physical ability,” Dr. Maija Marttinen, lead author of the review and scientist at DuPont Nutrition and Biosciences, said. “What is so exciting about this field of research is that with the growing number of published studies, we are able to delve deeper into the existing evidence and evaluate exactly what is happening in terms of gut bacteria and athletic performance.”
 
“We are always looking to conduct, gather, and analyze all the evidence of the benefits of probiotic supplementation,” Dr. Johanna Maukonen, global health and nutrition science R&D lead for Dupont said. “As leaders in the field of human health, it’s important to continue to push for more high-quality clinical studies to continue to uncover the roles gut microbiota and probiotics play in physical performance and the exact modes of actions behind their potential benefits.”

According to the authors of the study, the typical healthy adult gut is characterized by a high degree of diversity in microbes, which favors health-promoting species known to release beneficial enzymes and other endogenous chemicals that play a role in promoting health benefits to the immune system, mood, and other conditions. Exercise, likewise, is known to benefit the structure and function of the body in areas of cardiovascular health, immunity, metabolism, and mental health, and examinations of the plausible connection between gut health and physical fitness are underway but in their early stages. Evidence shows that gut microbiota are altered through exercise, with changes induced which are not present in sedentary people, perhaps in part because athletes are known to have a different dietary intake on average than a sedentary person – one clinical trial has shown that those who engage in at least 150 minutes of moderate-intensity exercise per week have greater concentrations of Akkermansai muciniphila, Faecalibacterium prausnitzii, and Roseburia hominis, three strains which are believed to modulate the inflammatory response. A study cohort of children between the ages of 7-18 in the American Gut Project also showed that physical activity, BMI, and diet were all associated with pronounced changes in the gut microbiota.
 
Smaller studies examining exercise interventions independently of diet, which tended to have smaller populations and less statistical significance, do show that sedentary people are able to alter the composition of the gut microbiome in a way that appears to be independent of dietary intake, which the authors theorize could be caused by changes in the maximum rates of oxygen consumption these study participants expanded.
 
One of the most challenging approaches to investigating the role the gut in physical performance is a study which involves metrics of physical performance as changed by a probiotic intervention, instead of looking at positive associations through the lens of an observational study, the authors said. Nonetheless, in vitro trials using animals have demonstrated that both muscle mass and endurance were reduced in mice who were either modeled to be germ free, or free of specific pathogens. Additionally, it has been shown that antibiotic treatment, which dramatically alters gut microbiota, reduces the endurance seen in mice, as does a reduction in the intakes of fermentable fibers. While germ-free animals are a more extreme model, they may establish a cause-effect relationship which manifests more subtly in humans.
 
Also in the review, the researchers theorize that the effects of probiotics on making one’s metabolism more ergogenic, and allowing the gut to synthesize more compounds known to benefit mood and muscle recovery likely play a role in the overall performance of athletes in the long-term.