Strategies to Manage Gastrointestinal Issues Reported by Endurance Athletes
Many endurance athletes worry that gastro-intestinal (GI) distress will ruin their training and/or competitive efforts. To learn what strategies athletes use to manage their GI concerns, PINES looked to Rachel Scriven, PhD student at the University of the Sunshine Coast in Queensland. Rachel has developed a questionnaire that assesses GI problems in athletes. Here is what she has to say regarding her research.
What is the background to this research?
The background of this research stems from part of my PhD studies
focussing on exercise-associated gastrointestinal symptoms (GIS) in endurance athletes. As many as 4-96% of endurance athletes report exercise-associated GIS that can vary from a mild inconvenience to severely impairing performance, which may lead to exercise cessation and/or withdrawal from activity (Costa, Snipe, et al., 2017). Exercise-associated GIS can develop in the upper- or lower-gastrointestinal regions or other related symptoms, such as nausea and stitch. Exercise-associated GIS develop through the neuro-endocrine- or circulatory-gastrointestinal pathways or through mechanical disruption, which are part of the exercise-induced gastrointestinal syndrome (EIGS) model (Costa, Snipe, et al., 2017; Gaskell et al., 2021). What is not currently known are the strategies endurance athletes implement to prevent or mitigate exercise-associated GIS around endurance exercise.
What was the aim of the study and how did you test this?
The primary aim of the study was to determine the self-reported incidence and severity of exercise-associated GIS in endurance athletes. The secondary aim was to review the typical strategies (dietary and non-dietary) self-selected by endurance athletes to manage their exercise-associated GIS, applying an original validated questionnaire (Scrivin et al., 2021; Scrivin et al., 2020).
What were the major findings of the study?
Endurance athletes reported higher incidence and severity of symptoms during exercise. No associations were found between biological sex, main sport, or level of participation for GIS incidence.
Endurance athletes predominantly categorised GIS severity as mild (≤4.9/10). The only severe symptom ( ≥5/10) of significance was the urge to defecate before (p=0.01) and during (p=0.001) exercise. The qualitative content review indicated popular dietary strategies endurance athletes tried to reduce GIS were dietary fibre reduction (n=42) and dairy avoidance (n=16), and non-dietary strategies included the use of medications (n=13).
The most successful dietary strategies to reduce GIS are fibre reduction, a low FODMAP diet and increasing carbohydrates. Nutritional supplements proposed to reduce or mitigate EIGS or exercise-associated GIS (but not substantially supported by research evidence) such as synbiotics and bovine colostrum were used infrequently or not tried by endurance athletes. The most important sources of information for the management of exercise-associated GIS were Accredited Practicing Dietitians (APD).
What are the practical applications of these findings?/How can sports dietitians use these findings?
Exercise-associated GIS in endurance athletes are commonly reported in endurance and ultra-endurance events. In the current study, the urge to defecate is the most common self-reported GIS, which is severe and may be substantial enough to interfere with exercise workload. Having an awareness that endurance athletes may experience exercise-associated GIS, particularly the urge to defecate, is important to consider when conducting a nutritional assessment or dietary intervention. The most successful strategies endurance athletes implemented to reduce GIS were a low FODMAP diet and a low-fibre high carbohydrate diet. Fibre reduction is supported in the literature as a dietary method to reduce exercise-associated GIS (Costa et al., 2019). A low FODMAP diet has been used successfully to treat irritable bowel syndrome (IBS) in non-athletic populations (National Institute for Health and Care Excellence, 2017). IBS presents with similar symptomatology as exercise-associated GIS.
Endurance athletes in the current study reported a reduction in symptoms when using a low FODMAP diet. If athletes are to implement a low FODMAP diet, qualified Dietitians must oversee this process to ensure nutritional adequacy. Training the gut with consuming carbohydrates (simple sugars) during endurance exercise has been shown to reduce exercise-associated GIS. This is possibly due to maintaining gut blood flow and supporting epithelial integrity, and/or improving gastrointestinal function and tolerance during endurance exercise, with potential performance benefits (Costa, Miall, et al., 2017; Miall et al., 2018; Rehrer et al., 2005; Snipe et al., 2017).
Read the full study here: Scrivin et al., (2021). Strategies reported amongst endurance athletes to manage exercise-associated gastrointestinal symptoms. Nutrition and Dietetics. https://onlinelibrary.wiley.com/doi/10.1111/1747-0080.12710
Author
Rachel Scriven, is a Registered Dietitian and Advanced Accredited Sports Dietitian in New Zealand with over 22 years of experience practicing in different settings from hospitals, community, government, sporting teams and private practice. She is currently a PhD student at the University of the Sunshine Coast in Queensland.
References
Costa, R. J. S., Hoffman, M. D., & Stellingwerff, T. (2019). Considerations for ultra-endurance activities: Part 1- nutrition. Res Sports Med, 27(2), 166-181. https://doi.org/10.1080/15438627.2018.1502188
Costa, R. J. S., Miall, A., Khoo, A., Rauch, C., Snipe, R., Camoes-Costa, V., & Gibson, P. (2017). Gut-training: the impact of two weeks repetitive gut-challenge during exercise on gastrointestinal status, glucose availability, fuel kinetics, and running performance. Appl Physiol Nutr Metab, 42(5), 547-557. https://doi.org/10.1139/apnm-2016-0453
Costa, R. J. S., Snipe, R. M. J., Kitic, C. M., & Gibson, P. R. (2017). Systematic review: Exercise-induced gastrointestinal syndrome-implications for health and intestinal disease. Aliment Pharmacol Ther, 46(3), 246-265. https://doi.org/10.1111/apt.14157
Gaskell, S. K., Rauch, C., & Costa, R. J. S. (2021). Gastrointestinal assessment and management procedures for exercise-associated symptoms. Aspetar Sp Med J, 10(22), 36-44.
Miall, A., Khoo, A., Rauch, C., Snipe, R. M. J., Camões‐Costa, V. L., Gibson, P. R., & Costa, R. J. S. (2018). Two weeks of repetitive gut‐challenge reduce exercise‐associated gastrointestinal symptoms and malabsorption. Scand J Med Sci Sports, 28(2), 630-640. https://doi.org/10.1111/sms.12912
National Institute for Health and Care Excellence. (2017). Irritable bowel syndrome in adults: diagnosis and management (Clinical guideline). www.nice.org.uk/guidance/cg61
Rehrer, N. J., Goes, E., DuGardeyn, C., Reynaert, H., & DeMeirleir, K. (2005). Effect of carbohydrate on portal vein blood flow during exercise. Int J Sports Med, 26(3), 171-176. https://doi.org/10.1055/s-2004-820957
Scrivin, R. A., Costa, R. J. S., Pelly, F. E., Lis, D., & Slater, G. J. (2021). Development and validation of a questionnaire investigating endurance athletes practices to manage gastrointestinal symptoms around exercise. Nutrition & Dietetics, 78(3), 286-295. https://doi.org/10.1111/1747-0080.12674
Scrivin, R. A., Slater, G. J., Costa, R. J., Pelly, F. E., & Lis, D. (2020). Endurance athletes sports nutrition beliefs, knowledge, information sources, and intended practices to manage gastrointestinal symptoms around exercise – Questionnaire. Qualtrics Core XM survey software. https://uniofsunshinecoast.syd1.qualtrics.com/jfe/form/SV_41wz4wGHK7ZbpB3
Snipe, R. M. J., Khoo, A., Kitic, C. M., Gibson, P. R., & Costa, R. J. S. (2017). Carbohydrate and protein intake during exertional heat stress ameliorates intestinal epithelial injury and small intestine permeability. Appl Physiol Nutr Metab, 42(12), 1283-1292. https://doi.org/10.1139/apnm-2017-0361
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