When thinking about athletic performance, the spotlight might usually fall on macronutrients and ingredients designed to enhance muscle tone, endurance, and recovery. However, we may also want to consider the connection between exercise and gut health. More specifically, recent research suggests that short-chain fatty acids (SCFAs), produced in the gastrointestinal tract, may play an important role in athletic performance.
What are SCFAs?
SCFAs, also known as postbiotics, are metabolites from the fermentation of dietary fibers and resistant starch by anaerobic bacteria in the GI tract. They are saturated aliphatic organic acids, consisting of one to six carbon atoms, with acetate (two carbons), propionate (three carbons), and butyrate (four carbons) being the most abundant. In the large intestine, the majority of the SCFAs are rapidly absorbed by the epithelial cells lining the colon and used to maintain intestinal barrier function.
SCFAs provide a connection between the microbiome, redox signaling, and host metabolism, and may play a supportive role in human health, due to their metabolic and signaling properties. Their functions have been attributed to their aliphatic tail length and the activation of specific membrane receptors. SCFAs may promote healthy oxidative and mitochondrial stress responses, healthy inflammatory responses, brain and metabolic health, and overall healthy aging.
The role of polyphenols in SCFA production
Polyphenols are compounds primarily found in fruit, vegetables, and spices. They have been shown to support antioxidant status, blood sugar metabolism, and healthy inflammatory and immune responses. Depending on the number of phenol rings and on the structural elements that bind these rings together, polyphenols can be categorized into several groups: flavonoids (e.g., quercetin), phenolic acids (e.g., curcumin and caffeic acid), lignans (e.g., sesamin and pinoresinol), and stilbenes (e.g., resveratrol). Due to their partial digestion by the host and the capacity to be fermented by intestinal microorganisms, polyphenols can be categorized as prebiotics.
Polyphenols play an important role in the GI microbiome composition and support the production of SCFAs. A systematic review of the prebiotic effects of polyphenols found that their consumption promotes certain beneficial commensal species, such as Lactobacillus, Bifidobacterium, Akkermansia, Roseburia, and Faecalibacterium and the production of SCFAs, including butyrate. Another review article came to similar conclusions regarding the role of polyphenols in promoting beneficial bacteria and increasing the production of their valuable metabolites, such as SCFAs.
The role of SCFAs in athletic performance
Recent research suggests that SCFAs may play a role in athletic performance and exercise recovery by supporting healthy inflammatory and immune responses and nutrient metabolism. Healthy inflammatory responses may promote faster muscle repair, which may be particularly relevant for athletes who need to recover quickly and limit muscle soreness after intense exercise.
SCFAs may also support energy availability during exercise and metabolic processes within the skeletal muscle. They can leave the gut via the portal vein and be taken up by the liver, where they can be used for lipid or carbohydrate synthesis. This can support energy demands during exercise by providing additional substrates for activated skeletal muscles. Thus, by supporting energy availability, SCFAs may promote endurance and performance during physical activity.
Furthermore, animal models have demonstrated that SCFAs may support exercise endurance and glycogen storage capacity in skeletal muscle. SCFAs may also promote muscle mass and mitigate muscle atrophy in aging mice by promoting metabolic signaling and healthy inflammatory responses. Interestingly, SCFAs have been shown to have certain effects on skeletal muscle metabolism that are similar to those observed by regular aerobic exercise training. Specifically, in animal models and cell lines, SCFAs have been shown to promote lipid metabolism and oxidation, glucose metabolism, and glycogen synthesis.
A healthy gut is essential for optimal nutrient absorption. By maintaining the integrity of the gut lining, SCFAs support efficient nutrient absorption and overall gut health, which may be particularly important for endurance athletes during long events. Further research in the form of human randomized controlled trials is warranted to fully investigate the effect of SCFAs on athletic performance. However, currently available research provides intriguing evidence for the supportive role that polyphenol consumption and SCFA production may play in elevating your exercise routine.
Learn more about SCFAs, polyphenols, and gut health:
How Polyphenols Promote a Healthy Gut Microbiome
Recent Review Explores Role of Probiotics in Sarcopenia and Gut-Muscle Axis
The Latest on Red Grape and Gut Microbial Health
Recent Review Explores Biochemical Relationship Between Gut Metabolites and Metabolic Health
By Antonia Toupet, PhD
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