Gastrointestinal Symptoms After Sport-Related Concussion: Prevalence and Patterns in a Multi-Cohort Analysis

Background/Objectives: Concussions occur across all sports globally; however, inconsistent symptom recognition continues to challenge diagnosis, management, and recovery. Although concussion effects extend beyond neurological dysfunction, gastrointestinal (GI) symptoms remain insufficiently captured within current assessment frameworks and may influence athletes’ fuelling choices and food tolerance during recovery. This study aimed to describe the prevalence and patterns of GI symptoms reported among athletes with a history of concussion and to explore whether symptom prevalence and burden differed by sex and country. Methods: A total of 401 adult athletes (225 males; mean age 32.4 ± 11.3 years) with a history of concussion were recruited from a multinational cohort (n = 123) and a US community rugby cohort (n = 278). Participants completed online surveys assessing concussion history, post-concussion symptoms (RPQ or SCAT-6), and GI-specific symptoms. Data were stratified by sex and country and analysed descriptively and comparatively. Results: Overall, 62.1% of athletes reported ≥1 GI symptom, with most reporting 1–5 symptoms (79.9%). The most frequent symptoms were nausea/vomiting (74.3%) and loss of/poor appetite (56.6%), followed by diarrhoea, abdominal pain/discomfort, and flatulence. Although GI symptom prevalence was higher in females (65.9% vs. 59.1%), no significant sex differences were observed (all p > 0.05). GI symptom burden varied by country (p < 0.001), with higher prevalence among Irish than US athletes (85.9% vs. 51.2%); however, these analyses were exploratory and unadjusted. RPQ and SCAT captured symptoms across somatic, cognitive, emotional, and sleep domains, however GI symptoms were underrepresented, with nausea/vomiting more frequently reported on RPQ/SCAT items (51.4%) than on GI-specific items (46.1%). Conclusions: GI symptoms were common following concussion, with variation by country and no statistically significant differences by sex. Findings indicate that concussion assessment tools (RPQ/SCAT) underrepresent the breadth of GI symptoms. Greater attention to GI assessment in concussion care is warranted. Incorporating simple GI screening alongside timely nutrition support may represent feasible additions to multidisciplinary, athlete-centred care pathways. Prospective studies are needed to clarify the clinical relevance of these findings and evaluate nutrition-related strategies.