by Susan J. Hewlings Ph.D., R.D.
Recent research has revealed that the balance of the bacteria in the gastrointestinal tracts affects a lot more than just the gut health of the host. The gut microorganisms have fundamental roles in many aspects of human biology, including metabolism, endocrine, neuronal and immune function.1 An imbalance in the microflora, called dysbiosis, is associated with increased susceptibility to infections as well as to non-communicable diseases like obesity, metabolic syndromes (e.g., diabetes and cardiovascular diseases), allergy and other inflammatory diseases.2 Recent findings have shown altered intestinal microbial communities and dysbiosis of the gut microbiota in circadian-disrupted mice and jet-lagged humans, indicating that stress and sleep disturbance can alter microbial balance.3 In addition, emerging evidence suggests a link between gut microbiota and the brain, thus suggesting that these microbes may play a role in neurological function as well as in perception, behavior and emotional responses of the host, all of which can significantly impact athletic performance.
The gut microbiome and its influence on host behavior, intestinal barrier and immune function are believed to be a critical aspect of the brain-gut axis.1 This has important implications for athletes, as fatigue, mood disturbances, under performance and gastrointestinal distress associated with over training are common among athletes during training and competition. This is not to dismiss that exercise that does not result in overtraining also induces a level of “stress" to homeostatic mechanisms that ultimately result in training adaptations. Associated with these can be a stress-related release of catabolic hormones, inflammatory cytokines and microbial molecules all of which can influence microbial balance.
It has been suggested that gut microbiota might have a key role in controlling the oxidative stress and inflammatory responses as well as improving metabolism and energy expenditure during intense exercise.4 The exact connection between exercise-induced stress, the associated adaptations, over training, the gut microbiota and performance have not been clearly identified. What is clear is that it may be possible to design diet and supplemental strategies to optimize microbial balance and optimize performance through the gut-brain axis.1,2 For example, change in diet can significantly influence the composition of the gut microbiota composition in just 24 hours.5
The use of probiotics to modify the microbiota has also been identified as an important therapeutic tool to improve athletes' overall general health, performance, and energy availability while controlling inflammation and redox levels.4 Therefore, any discussion of the cognitive aspect of sports nutrition must include a review of the literature related to exercise-induced stress and its influence on the microbiota via the gut brain axis, as well as its impact on an athlete’s health and performance.
|For more, check out the Sports Ingredient Marketplace session on Ingredients for the Mental Game, scheduled for Tuesday, April 18, during Ingredient Marketplace in Orlando. The Sports education was developed in conjunction with the International Society for Sports Nutrition (ISSN) and is sponsored by International Dehydrated Foods (IDF), CHiKPRO™ and OptiMSM®.|
Susan Hewlings, Ph.D., RD, is the co-founder of Substantiation Sciences, a professor at Central Michigan University and chief science director for IgY Nutrition. Dr. Hewlings specializes in substantiation from study design to publication. She has over 15 years of experience in the industry and has published in multiple peer reviewed journals, text books and trade publications. She received her doctorate in nutrition, her master’s in exercise physiology and her bachelor’s in nutrition from Florida State University.
- Clark A and Mach N. “Exercise-induced stress behavior, gut-microbiota-brain axis and diet: a systematic review for athletes.” J Int Soc Sport Nutr. 2016;13:43.
- Sirisinha, S. “The potential impact of gut microbiota on your health: Current status and future challenges.” Asian Pac J Allergy Immunol. 2016 Dec;34(4):249-264.
- Reynolds, AC et al. “The shift work and health research agenda: Considering changes in gut microbiota as a pathway linking shift work, sleep loss and circadian misalignment, and metabolic disease.” Sleep Med Rev. 2016 Jul 11. Online ahead of print.
- Mach N and Fuster-Botella D “Endurance exercise and gut microbiota: A review.” J Sport Health Sci 2016; 1-19.
- David LA et al. “Diet rapidly and reproducibly alters the human gut microbiome.” Nature. 2014;505:559–63.