Nutritional indicators for gastrointestinal symptoms in female runners: the ‘Marikenloop study’

OBJECTIVES Among runners the reported prevalence of exercise-induced gastrointestinal (GI) symptoms is high (25%-83%). We aimed to investigate the prevalence of GI symptoms in women during a 5-10 km run in general and to explore the association between nutritional intakes and GI symptoms. SETTING As part of the Marikenloop-study (a cohort study to identify predictor variables of running injuries), a cross-sectional questionnaire was distributed in interested runners of the '2013 Marikenloop'. PARTICIPANTS 433 female runners filled in the questionnaire. PRIMARY AND SECONDARY OUTCOME MEASURES The primary outcome measure was the frequency of running-related GI symptoms during running in general and during the last (training) run. Furthermore, dietary intake was determined before and during this run. Secondary outcome measures were several demographic and anthropometric variables. RESULTS During running in general, 40% of the participants suffered from GI symptoms and during their last run, 49%. The GI symptoms side ache, flatulence, urge to defecate and regurgitation and/or belching were most commonly reported. Lower age (OR=0.98, 95% CI 0.96 to 1.00), minor running experience (OR=3.1, 95% CI 1.7 to 5.7), higher body mass index (OR=1.1, 95% CI 1.0 to 1.2), consuming carbohydrate-containing drinks during running (OR=10.5, 95% CI 1.4 to 80.3) and experiencing GI symptoms during running in general OR=5.0, 95% CI 3.2 to 7.8) significantly contributed to GI symptoms during the last run in the logistic regression analysis. In contrast, time of eating and carbohydrate-containing drinks consumed prior to the run were not related to GI symptoms. CONCLUSIONS In conclusion, the current study confirms the high prevalence of GI symptoms in female runners. Several predictor variables contributed to the GI symptoms but more research is needed to specify the effects of prerunning eating and carbohydrate-containing drinks on GI symptoms during running. TRIAL REGISTRATION NUMBER Marikenloop study 2013: 50-50310-98-156 (ZonMw).