Protein and Exercise-Induced Gastrointestinal Symptoms

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.

Study Overview

• Status: Completed
• Conditions: Gastro-Intestinal Disorder
• Intervention / Treatment: Dietary supplement: Whey protein

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 13
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jill A Parnell, PhD; Phone Number: 4034408672; Email: jparnell@mtroyal.ca
• Study Contact Backup: Name: Robyn F Madden, PhD; Phone Number: 4033633080; Email: rmadden@mtroyal.ca

Study Locations

• Canada
  • Alberta
    • Calgary, Alberta, Canada, T3E 6K6
      • Mount Royal University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Low Protein; Protein intake at 0.15g/kg body weight	Dietary supplement: Whey protein; Weight protein provided in a shake with carbohydrate and water
Experimental: High Protein; Protein intake at 0.4 g/kg body weight	Dietary supplement: Whey protein; Weight protein provided in a shake with carbohydrate and water

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: Mount Royal University
• Investigators: Principal Investigator: Jill A Parnell, PhD, Mount Royal University

Publications and helpful links

General Publications

• Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Acad Nutr Diet. 2016 Mar;116(3):501-528. doi: 10.1016/j.jand.2015.12.006. Erratum In: J Acad Nutr Diet. 2017 Jan;117(1):146.
• Briggs MA, Harper LD, McNamee G, Cockburn E, Rumbold PLS, Stevenson EJ, Russell M. The effects of an increased calorie breakfast consumed prior to simulated match-play in Academy soccer players. Eur J Sport Sci. 2017 Aug;17(7):858-866. doi: 10.1080/17461391.2017.1301560. Epub 2017 Mar 21.
• Costa RJS, Snipe RMJ, Kitic CM, Gibson PR. Systematic review: exercise-induced gastrointestinal syndrome-implications for health and intestinal disease. Aliment Pharmacol Ther. 2017 Aug;46(3):246-265. doi: 10.1111/apt.14157. Epub 2017 Jun 7.
• Kerksick CM, Arent S, Schoenfeld BJ, Stout JR, Campbell B, Wilborn CD, Taylor L, Kalman D, Smith-Ryan AE, Kreider RB, Willoughby D, Arciero PJ, VanDusseldorp TA, Ormsbee MJ, Wildman R, Greenwood M, Ziegenfuss TN, Aragon AA, Antonio J. International society of sports nutrition position stand: nutrient timing. J Int Soc Sports Nutr. 2017 Aug 29;14:33. doi: 10.1186/s12970-017-0189-4. eCollection 2017.
• Parnell JA, Wagner-Jones K, Madden RF, Erdman KA. Dietary restrictions in endurance runners to mitigate exercise-induced gastrointestinal symptoms. J Int Soc Sports Nutr. 2020 Jun 10;17(1):32. doi: 10.1186/s12970-020-00361-w.
• Pfeiffer B, Stellingwerff T, Hodgson AB, Randell R, Pottgen K, Res P, Jeukendrup AE. Nutritional intake and gastrointestinal problems during competitive endurance events. Med Sci Sports Exerc. 2012 Feb;44(2):344-51. doi: 10.1249/MSS.0b013e31822dc809.

Study record dates

Study Major Dates

• Study Start (Actual): March 13, 2019
• Primary Completion (Actual): December 21, 2023
• Study Completion (Actual): December 21, 2023

Study Registration Dates

• First Submitted: March 22, 2023
• First Submitted That Met QC Criteria: May 10, 2023
• First Posted (Actual): May 11, 2023

Study Record Updates

• Last Update Posted (Actual): March 21, 2024
• Last Update Submitted That Met QC Criteria: March 20, 2024
• Last Verified: March 1, 2024

More Information

Terms related to this study

• Keywords: Runners; Dietary protein; Gastrointestinal symptoms
• Additional Relevant MeSH Terms: Gastrointestinal Diseases; Digestive System Diseases; Intestinal Diseases
• Other Study ID Numbers: MountRoyalU

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No