The effect of prebiotic carrot fiber supplementation on Exercise-Induced Gastrointestinal Syndrome in Response to Exertional-Heat Stress of runners.

Abstract

Gastrointestinal (GI) distress is one of the main factors that impact the performance and health of ultramarathon runners. The exercise-induced gastrointestinal syndrome is an observed condition in prolonged sports, and might result in several clinical and performance implications. In order to ameliorate these responses, nutritional strategies have been proposed. Prebiotic supplementation seems to affect the intestinal microbiota, but there are no studies that assess its effect on GI responses to exercise. Considering this, the study aims to determine the effects of prebiotic carrot fiber supplementation on biomarkers of gastrointestinal integrity in response to exertional-heat stress. One week after the initial assessment, participants (n=12) will be allocated in a double-blind randomized and counterbalanced order to complete 2 experimental trials, with at least 1 week washout. Trials included a water control trial (CON) and a prebiotic carrot fiber intervention trial (INT). On INT, participants will be asked to consume a dose of prebiotic carrot fiber two times a day (morning and afternoon), for 7 days before the exertional-heat stress, and one dose immediately before, and every 20 min during 2h running at 60% maximal oxygen uptake in 35°C ambient conditions. A water volume equivalent will be provided on CON. Whole blood samples will be collected pre-, immediately post-, 1 and 2 h postexercise, and analyzed for plasma concentrations of cortisol, intestinal fatty acid protein, soluble CD14, and immunoglobulin M (IgM) by ELISA, and systemic inflammatory cytokines by multiplex. It is expected that prebiotic carrot fiber supplementation will ameliorate markers reflective of intestinal epithelial cell injury and epithelial hyperpermeability, and systemic inflammatory responses.