Impact of a Probiotic-based Formula on Digestive Symptoms and Mood in Ultra Marathon Runners

Evaluation of the Impact of a Probiotic-based Formula on Digestive Symptoms, General Symptoms and Mood in Ultra Runners

Randomized, prospective, double-blind, placebo-controlled study in ultramarathon runners to evaluate the effects of suplementation with i3.1 probiotic formulation on the relief of common digestive symptoms associated to intense physical exercise. Secondary study outcomes aim to evaluate the effect of the probiotic formulation on fatigue, discomfort and muscle pain, as well as anxiety and mood.

Gastrointestinal symptoms (GIS) are a common feature of intense exercise, especially in ultra-endurance events. The main objective of this study is to evaluate the impact of a 3-strain probiotic formulation comprising Lactiplantibacillus plantarum and Pediococcus acidilactici on digestive symptoms in a maximum of 300 runners registered in an organized ultra-marathon event. A randomized, prospective, double-blind, placebo-controlled study will be conducted. Once recruited, participants will be allocated to recieve either the probiotic or placebo (at a ratio 2:1) for 4 weeks prior to race day. During follow-up, study participants will fulfill several questionnaires at specific time points (baseline, week -3, -2, -1, -24 h previous to the race, as well as 24 h and 7 days after the race). This will be documented through a specifically designed, web-based platform. Digestive symptoms will be evaluated through validated questionnaires: modified from Pfeiffer et al (2012; main outcome) and the Gastrointestinal Symptoms Rating Scale (GSRS). Secondary objectives will comprise anxiety, mood, other symptoms (muscle pain, fatigue, respiratory symptoms), and performance in the ultra-marathon.

Inclusion Criteria:

• Age >18 years
• Correctly registered in the Salomon Ultra Pirineu 100K® 2023 race
• Stable medication planned during the study period
• Willing to provide informed consent and follow study procedures
• Have signed the consent provided by the organization of the Salomon Ultra Pirineu 100K® 2023 race

Exclusion Criteria:

• Respiratory, gastrointestinal or systemic infection that has caused fever or fatigue in the 15 days prior to the study entry
• Having taken probiotic-based supplements or dairy products with probiotics (including "Actimel" or yogurts with "bifidus") daily in the 15 days prior to the study start
• Taking oral or parenteral antibiotics in the 15 days prior to the study start
• History of gastrointestinal surgery within 6 months prior to the study start
• History of cardiovascular event: angina, heart failure, myocardial infarction
• Diabetes mellitus type 1 or 2
• Pregnancy or lactation, or women planning to conceive during the study period
• Chronic gastrointestinal disease: inflammatory bowel disease (Crohn's disease, ulcerative colitis), pancreatitis, short bowel syndrome
• Gastrointestinal disease or disorders: inflammatory bowel disease (ulcerative colitis, Crohn's disease), irritable bowel syndrome, chronic diarrhea or constipation
• Diagnosis of severe kidney disease (chronic kidney failure) or liver disease (hepatitis, cholestasis, liver failure)