Is there a relationship between eating behaviours and lower gastro-intestinal (GI) symptoms in female runners? An exploratory study

By Sarah Kekus


Current literature suggests that GI disturbances are common complaints amongst runners. Studies of both the general population and the running community have found that women report more GI symptoms than men; diverse theories for gender-related differences have been proposed, with psychosocial factors and fluctuating female sex hormones being frequently explored. Looking specifically at female runners, it is thought that over 80% have abnormal menstrual cycles and several studies have explored the impact of chronic energy insufficiency on menstrual status.
Against this backdrop, specific dietary behaviours, including calorie restriction, have been investigated amongst a group of female runners. The main aim of this study was to ascertain if dietary behaviours amongst this group are contributing to their GI symptoms. Key objectives were to recruit a group of symptomatic female runners, capture information on their dietary practices as well as the nature/severity of the symptoms they experience and evaluate the data.

The online survey tool, Survey Monkey was used to capture the data and 67 participants were recruited by email from across the UK, with running clubs specifically targeted. Only women aged between 20-50, who had experienced GI discomfort within the two months prior to completing the questionnaire, were included. Forty-nine questionnaires were complete with all inclusion/exclusion criteria having been met. The responses were evaluated using both qualitative thematic analysis and quantitative analysis. Using just statistical analysis was deemed inadequate, due to the small number of participants, whereas using qualitative analysis enabled the capturing of rich contextual data appropriate to the research question. Stool type was used to establish four main symptom categories; this enabled dietary behaviours to be examined in relation to each category.

The findings suggest that a low intake of dietary protein is associated with an increased incidence of diarrhoea and bloody stools. A low intake of vegetables, a high intake of fruit and calorie restriction combined with high mileage were also found to correlate with an increased incidence of GI symptoms.

Consistent with other studies, the findings suggest that sub optimal hydration and/or a high usage of sports gels also increase the likelihood of GI disturbance. A finding specific to this study is that a high percentage of total calorie intake from sugar correlates with a significantly increased incidence of diarrhoea and bloody stools.

This study concludes that cognitive dietary restraints play a role in the development of GI symptoms amongst female runners. Further exploration of the potential effects of low levels of ovarian hormones (as a result of chronic energy deficiency) on GI symptoms is recommended. In addition, further studies of dietary behaviours amongst men and asymptomatic women are recommended in order to fully appreciate how relevant these finding are.