Effect of a short-term low fermentable oligosaccharide, disaccharide, monosaccharide and polyol (FODMAP) diet on exercise-related gastrointestinal symptoms
Melanie Wiffin, Lee Smith, Jose Antonio, James Johnstone, Liam Beasley, Justin Roberts
Journal of the International Society of Sports Nutrition
Research has demonstrated that low fermentable oligosaccharide, disaccharide, monosaccharide and polyol (FODMAP) diets improve gastrointestinal (GI) symptoms in irritable bowel syndrome sufferers. Exercise-related GI issues are a common cause of underperformance, with current evidence focusing on the use of FODMAP approaches with recreationally competitive or highly trained athletes. However, there is a paucity of research exploring the potential benefit of FODMAP strategies to support healthy,
... recreational athletes who experience GI issues during training. This study therefore aimed to assess whether a short-term LOW FODMAP diet improved exercise-related GI symptoms and the perceived ability to exercise in recreational runners. Methods: Sixteen healthy volunteers were randomly assigned in a crossover design manner to either a LOW FODMAP (16.06 ± 1.79 g·d − 1 ) or HIGH FODMAP (38.65 ± 6.66 g·d − 1 ) diet for 7 days, with a one week washout period followed by a further 7 days on the alternate diet. Participants rated their gastrointestinal symptoms on an adapted version of the Irritable Bowel Syndrome-Severity Scoring System (IBS-SSS) questionnaire before and at the end of each dietary period. Perceived ability to exercise (frequency, intensity and duration) in relation to each dietary period was also rated using a visual analogue scale. Resting blood samples were collected prior to and on completion of each diet to determine plasma intestinal fatty acid binding protein (I-FABP) as a marker of acute GI injury. Results: Overall IBS-SSS score significantly reduced in the LOW FODMAP condition from 81.1 ± 16.4 to 31.3 ± 9.2 (arbitrary units; P = 0.004). Perceived exercise frequency (z = 2.309, P = 0.02) and intensity (z = 2.687, P = 0.007) was significantly improved following a short-term LOW FODMAP approach compared to HIGH FODMAP . No significant differences were reported between dietary conditions for plasma I-FABP (P > 0.05). Conclusions: A short-term LOW FODMAP diet under free-living conditions reduced exercise-related GI symptoms and improved the perceived ability to exercise in otherwise healthy, recreational runners. These findings may be explained by a reduction in indigestible carbohydrates available for fermentation in the gut. The therapeutic benefits of LOW FODMAP diets in recreational and trained athletes during sustained training periods warrants further investigation.