Nutritional strategies for minimizing gastrointestinal symptoms during endurance exercise: systematic review of the literature.

Background: The gastrointestinal (GI) tract plays a critical role in achieving peak athletic performance either during training or in competitions. Despite its significance, the GI tract's role in the training process of athletes is often neglected, resulting in frequent GI symptoms. These disturbances are particularly prevalent in endurance sports, where GI function is commonly compromised, leading to adverse effects on performance. In this review, we examine potential nutritional causes of the GI symptoms and provide possible solutions to mitigate them, aiming to enhance athletes' overall performance and well-being.

Methods: PRISMA methodology was used to search through PubMed Database from January 2023 to March 2023. The selected studies were comprised of randomized controlled trials, crossover trials and case studies.

Results: Twenty-nine studies met the inclusion criteria for this systematic review. The studies were categorized into five distinct areas of research on GI symptoms in endurance exercise: gut training protocols, effects of different carbohydrate solutions and mixtures, low FODMAP diet, hydrogel CHO technology, and probiotic supplementation.Gut training protocols seem promising in improving GI symptoms over time. Optimizing carbohydrate intake during exercise according to current recommendations has been associated with lower incidence and severity of GI symptoms as well. The low FODMAP diet also shows potential to reduce GI symptoms, although its restrictive nature could negatively affect athletes in other ways. Hydrogel carbohydrate products, at present, do not demonstrate any benefits over standard carbohydrate products. Probiotic supplementation shows mixed evidence regarding its effectiveness in alleviating and reducing GI symptoms during endurance exercise.

Conclusion: We have acknowledged that the onset of GI symptoms is very complex, and that onset is influenced by a huge variety of factors. It should be emphasized that the elimination of GI symptoms in each athlete must be approached individually and thoughtfully.