Protein and Exercise-Induced Gastrointestinal Symptoms

Study Overview
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Brief Summary
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Recommendations for carbohydrate intakes in the pre-exercise meal for endurance athletes are available; however, are lacking protein. Therefore, the purpose of this study is to quantify exercise-induced gastrointestinal symptoms and gut fullness occurring in response to a low protein (control) and a high protein (intervention) pre-exercise meal. The secondary purpose is to quantify blood glucose responses to a high-protein pre-exercise meal as compared to a low-protein control.

Detailed Description
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Context: Proper nutrition is crucial for peak sport performance. Recommendations for carbohydrate intakes in the pre-exercise meal for endurance athletes are available; however, are lacking for protein. Furthermore, a recent position statement regarding nutrient timing for exercise also lacks protein recommendations. The only advice provided is to avoid too much as it may cause gastrointestinal (GI) discomfort. The aforementioned recommendation provides no guidance as to how much is too much nor, to our knowledge, is there any clinical trial data to support the position. Exercise-associated gastrointestinal symptoms are a common cause of withdrawal from competition; thus, athletes need to consider the impact of dietary choices on gastrointestinal (GI) symptoms, as well as performance. Exercise induced GI symptoms can plague all athletes; but the effects seem to be most pronounced in endurance running. The reported prevalence of exercise-induced GI disturbances varies depending on methodology; however a questionnaire administered by the investigator's lab to 440 runners found 41% experienced stomach pain/cramps, 24% had intestinal issues, and over 20% reported bloating, diarrhea and/or gas. Exercise related GI complaints have been broadly related to diet. Research from the investigator's lab has found that many of the top foods that are avoided pre-running, to reduce GI symptoms, are those classified as high in protein (legumes, meat, poultry, fish, milk). These observations are based on self-reported data from experienced runners, and require testing in a clinical setting. Objectives: 1) to quantify exercise induced gastrointestinal symptoms and gut fullness occurring in response to a low protein (control) and high protein (intervention) pre-exercise meal. 2) to quantify blood glucose responses to a high protein pre-exercise meal as compared to a low protein control. Methods: The study is a single blind crossover design. Endurance runners will be ask to standardize their exercise 3-days prior to testing. The participants will be asked to eat a similar meal in the 24-12 hours pre-testing and fast for 12 hours pre-testing. The participants will be assigned to consume a pre-exercise shake with carbohydrate at 0.75g/kg body weight + water at 5ml/kg body weight and either low whey protein control or high whey protein intervention one hour pre-exercise in a randomized fashion. Participants will then complete a 10 km running protocol at 85% of the participant's race pace on a treadmill in an temperature and humidity controlled room. Gastrointestinal symptoms via self-report questionnaire and blood glucose will be measured at fasting, during the one hour digestive period and post-exercise.

Official Title
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Protein and Exercise-Induced Gastrointestinal Symptoms

Conditions
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Gastro-Intestinal Disorder

Intervention / Treatment
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* Dietary Supplement: Whey protein


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: recreational competitive runners, defined as running at least 25 km per week experiences exercise-induced gastrointestinal symptoms while running Exclusion Criteria: individuals with food allergies, gastrointestinal disorders (e.g., celiac disease, irritable bowl syndrome, etc.) adherence to a special diet pregnancy pre-existing medical condition that would prevent them from completing the prescribed exercise blood-borne illness

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 59 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Crossover intervention; all participants will have a low protein and a high protein session.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Low Protein<br>Protein intake at 0.15g/kg body weight | Dietary Supplement: Whey protein<br>* Weight protein provided in a shake with carbohydrate and water<br>|
| Experimental: High Protein<br>Protein intake at 0.4 g/kg body weight | Dietary Supplement: Whey protein<br>* Weight protein provided in a shake with carbohydrate and water<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Self-report exercise induced gastrointestinal symptoms | Quantify exercise induced gastrointestinal symptoms via a 0-9 point Likert scale questionnaire including 6 questions for upper abdominal problems, 7 questions for lower abdominal problems and 5 systemic problems. Likert scale questions are administered at fasting, pre-exercise and post-exercise. Questionnaires are administered in response to a low protein (control) and a high protein pre-exercise meal. | 3 hours per session | 
| Gut fullness | Gut fullness measured using a 100mm visual analogue scale anchored by not full at all and very full at fasting 15, 30 and 60 minutes post-meal and post run. Questionnaires are administered in response to a low protein (control) and a high protein pre-exercise meal. | 3 hours per session | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma glucose levels | Quantify blood glucose levels via a finger prick and blood glucose meter in response to a high protein pre-exercise meal as compared to a low protein control at fasting, 30 minutes post meal, 60 minutes post-meal and post 10 km run. | 3 hours per session | 
| Perceive exertion | Perceived exertion during the 10 km challenge run will be measured via Borg Rating of Perceived Exertion scale post run. | 1 hour per session | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Dietary protein, Runners, Gastrointestinal symptoms