The association between gastrointestinal injury, -complaints, and food intake in 60 km ultramarathon runners

Purpose We aimed to assess the association between gastrointestinal (GI) injury, -complaints, and food intake in 60 km ultramarathon runners. Methods Thirty-three ultramarathon runners provided pre- and post-race blood samples for assessment of GI injury by intestinal fatty-acid binding protein (I-FABP), and inflammatory response by IL-6, IL-8, TNF-α, and CRP. GI complaints and nutritional intake were reported by a post-race questionnaire. Results GI complaints were reported by 73% of the runners, of which 20% reported one or two severe complaints. IL-6, IL8, TNF-α, and CRP increased significantly from pre- to post-race (P<0.001 for all biomarkers), while I-FABP did not (1375 [IQR: 1264-2073] to 1726 [IQR: 985-3287] pg/mL; P=0.330). The 'GI-complaints score', as the integral of the number and severity of GI complaints, did not correlate with ∆I-FABP (rs:-0.050; P=0.790) or energy intake (rs:-0.211; P=0.260). However, there was a significant negative correlation between energy intake and ∆I-FABP (rs:-0.388; P=0.031). Conclusion GI complaints were neither associated with food intake nor GI injury as assessed by plasma I-FABP response. Energy intake, however, was inversely related to the I-FABP response to exercise. This finding suggests that substantial energy intakes during exercise may prevent exercise-induced GI injury as assessed by the I-FABP response. Novelty bullets • No association between gastrointestinal complaints and gastrointestinal injury (I-FABP response) or food intake was present. • There was an inverse correlation between energy intake and plasma I-FABP response, suggesting that higher energy intakes may prevent gastrointestinal injury as assessed by the I-FABP response.