Sport Supplements and the Athlete’s Gut: A Review

Abstract

Vigorous or prolonged exercise poses a challenge to gastrointestinal system functioning and is associated with digestive symptoms. This narrative review addresses 1) the potential of dietary supplements to enhance gut function and reduce exercise-associated gastrointestinal symptoms and 2) strategies for reducing gastrointestinal-related side effects resulting from popular sports supplements. Several supplements, including probiotics, glutamine, and bovine colostrum, have been shown to reduce markers of gastrointestinal damage and permeability with exercise. Yet, the clinical ramifications of these findings are uncertain, as improvements in symptoms have not been consistently observed. Among these supplements, probiotics modestly reduced exercise-associated gastrointestinal symptoms in a few studies, suggesting they are the most evidenced-based choice for athletes looking to manage such symptoms through supplementation. Carbohydrate, caffeine, and sodium bicarbonate are evidence-based supplements that can trigger gastrointestinal symptoms. Using glucose-fructose mixtures is beneficial when carbohydrate ingestion is high (>50 g/h) during exercise, and undertaking multiple gut training sessions prior to competition may also be helpful. Approaches for preventing caffeine-induced gastrointestinal disturbances include using low-to-moderate doses (<500 mg) and avoiding/minimizing exacerbating factors (stress, anxiety, other stimulants, fasting). Adverse gastrointestinal effects of sodium bicarbonate can be avoided by using enteric-coated formulations, low doses (0.2 g/kg), or multi-day loading protocols.

Occurrence and Impacts of Gastrointestinal Symptoms in Team-Sport Athletes: A Preliminary Survey

“…It is well recognized that gastrointestinal (GI) symptoms are prevalent among individuals partaking in endurance exercise, although estimates vary with factors such as exercise intensity, age, sex, training experience, nutritional intake, supplement use, and psychological state. [1][2][3][4][5] Using a prospective design, Wilson 6 found that male and female runners experienced at least one GI symptom on 84% and 78% of their runs, respectively, over a 30-day period, and moderate-to-severe symptoms ($5 on a 0-10-scale) were experienced on 14% to 22% of runs. Competition-related GI symptoms are also commonplace, with $90% of ultra-endurance race (100-mile runs, 70.3-mile triathlons, etc.)…”

Competitive season effects on polyunsaturated fatty acid content in erythrocyte membranes of female football players

“…), we observed a hypoactivity in the conversion from LA to DGLA. Moreover, this deficit might be connected to an alteration of the immune system [ 58 , 59 ] and intestinal health, including intestinal permeability, expected to be disrupted when increasing training loads [ 60 ], which in turn is related to the inflammatory status [ 61 ] as explained previously, being DGLA a precursor of AA.…”

Different Approaches to Ergogenic, Pre-, and Probiotic Supplementation in Sports with Different Metabolism Characteristics: A Mini Review

“…However, it was found that NaHCO 3 at doses over 0.2 g/kg b.w. can acutely trigger adverse gastrointestinal symptoms [ 30 ]. These symptoms include diarrhea, which not only leads to dehydration but also microbiota disturbances.…”