Synbiotic Supplementation in Cyclists

The Effect of a Synbiotic Formulation on Endurance Exercise Performance in Trained Cyclists: A Randomized, Double-Blinded, Placebo-Controlled, Parallel Trial

The goal of this clinical trial is to assess the efficacy of a synbiotic blend on exercise performance and other exercise parameters in trained adult cyclists. It is hypothesized that those taking the synbiotic blend will have improved endurance exercise performance.

The primary objective is to assess the impact of a synbiotic on 20km distance trial performance in 36 cyclists. Secondary objectives include assessing the impact of the synbiotic on exercise metabolism, body composition, gastrointestinal and immune health.

Study Overview

• Status: Completed
• Conditions: Exercise Endurance
• Intervention / Treatment: Dietary supplement: Synbiotic; Dietary supplement: Placebo

Detailed Description

The goal of this randomized double-blinded clinical trial is to evaluate the potential beneficial effects of a synbiotic formulation on exercise performance in trained adult cyclists. The main questions it aims to answer are related to the Synbiotic effects on:

• Cycling performance
• Exercise metabolism
• Gastrointestinal health
• Immune system
• Body composition
• Fecal Short Chain Fatty Acids (SCFAs)
• Fecal microbiome composition

Participants will be recruited and, if consenting and eligible, will undergo the initial pre-testing phase for baseline assessment (4 on-site visits). Then, they will be randomized to receive the synbiotic or placebo and instructed to consume one sachet daily for 42 consecutive days. After 4-5 weeks of intervention (Day 33), post-testing phase will start, and participants will be asked to return to the site to perform post testing assessments (over 4 on-site visits). Study visits will occur as follows, V1 (Day -9), V2 (Day -6), V3 (Day -3), V4 (Day 0), V5 (Day 33), V6 (Day 36), V7 (Day 39), and V8 (Day 42).

Researchers will compare the assessed outcomes to baseline in each group and evaluate the difference between groups following the synbiotic consumption to highlight any statistically and clinically relevant observations.

• Study Type: Interventional
• Enrollment (Actual): 22
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Alberta
    • Calgary, Alberta, Canada, T2N 1N4
      • University of Calgary

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Male or female between the ages of 18-45
• Currently cycling for at least 3 hours per week for the past 3 months
• Free of any contraindications to exercise and any medical condition that could interfere with or influence metabolic or cardiovascular responses to exercise
• Have a resting heart rate <100 bpm and resting systolic and diastolic blood pressures <160 mmHg and <90 mmHg, respectively.

Exclusion Criteria:

• Use of antibiotics or probiotic products within 4 weeks prior to study enrollment (note: participants will be eligible after a 2-week washout period)
• Current laxative use
• Are a smoker or use tobacco products
• Consume >21 units of alcohol per week
• Have donated blood in the previous 3 months
• Have a BMI ≥30kg/m2
• Are pregnant or lactating or planning to become pregnant for the duration of the study
• Are dieting for weight loss or are following a low carbohydrate diet
• Have participated in another clinical trial within the 30 days preceding study enrollment
• Are taking medications known to affect cardiovascular or metabolic responses to exercise
• Have a medical condition that could interfere with study intervention and assessment
• Have current musculoskeletal injuries that limit exercise capacity
• Are non-English speaking

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Synbiotic; Participants receive the synbiotic for 6 weeks.	Dietary supplement: Synbiotic; Combination of a probiotic and prebiotic. Daily administration in a single dose in powder form.
Placebo Comparator: Placebo; Participants receive the placebo for 6 weeks.	Dietary supplement: Placebo; Placebo. Daily administration in a single dose in powder form.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in endurance exercise performance measured during a 20km cycling distance trial	Assessed as time (minutes) to complete 20km cycling distance	42 Days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in maximal oxygen consumption (V̇O2max) measured during a Step-Ramp-Step Test	Assessed as mL·kg-1·min-1 measured through expired air collection	36 Days
Change in peak power output (PPO) measured during a Step-Ramp-Step Test	Assessed as highest power output in Watts	36 Days
Change in power output corresponding to the gas exchange threshold (GET) and respiratory compensation point (RCP)	Assessed as power output in Watts at GET and RCP	36 Days
Change in time to exhaustion measured during a cycling session at 85% of the peak power output	Assessed as time (minutes) to reach volitional exhaustion.	39 Days
Change in fat and carbohydrate oxidation measured during exercise sessions	Assessed with the nonprotein respiratory quotient equation using expired air variables (VO2 and VCO2)	36, 39 and 42 Days
Change in blood lactate concentration measured via pinprick capillary blood test	Assessed as mmol/L in capillary blood	36, 39 and 42 Days
Change in body composition measured by dual energy X-ray absorptiometry (DXA)	Assessed as percent fat and muscle mass (%) with a DXA scan	33 Days
Change in intestinal permeability markers measured in serum	Assessed in serum as pg/ml (Zonulin, Irisin, and Claudin2)	33 Days
Change in cytokines	Assessed in serum as fg/ml (IFN-γ, IL-10, IL-12p70, IL-17, IL-1β, IL-2, IL-4, IL-6, TNF-α)	33 Days
Change in gastrointestinal symptoms measured by self-report	Assessed via subjective ratings on a Patient-Reported Outcomes Measurement Information System® (PROMIS®)-GI scale	33 Days
Change in fecal SCFA concentration measured by gas chromatography	Assessed as µmol/L of fecal SCFAs (acetate, butyrate, propionate, and total SCFAs)	33 Days
Synbiotic strains quantification measured by qPCR in fecal matter	Assessed as 16S rRNA gene copies determined with qPCR	33 Days from Day 0
Change in fecal microbiota composition	Assessed as relative abundance of the 16S rRNA amplicon obtained via sequencing	33 Days
Incidence of adverse events	Assessed as the number of adverse events and serious adverse events reported	42 Days

Collaborators and Investigators

• Sponsor: University of Calgary
• Collaborators: Lallemand Health Solutions
• Investigators: Principal Investigator: Raylene A Reimer, PhD, RD, University of Calgary

Study record dates

Study Major Dates

• Study Start (Actual): July 15, 2024
• Primary Completion (Actual): December 23, 2024
• Study Completion (Actual): December 23, 2024

Study Registration Dates

• First Submitted: February 26, 2024
• First Submitted That Met QC Criteria: March 1, 2024
• First Posted (Actual): March 8, 2024

Study Record Updates

• Last Update Posted (Actual): May 1, 2026
• Last Update Submitted That Met QC Criteria: April 27, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Exercise; Prebiotic; Gut microbiota; Probiotic; Athlete; Metabolism; Synbiotic; Cyclists
• Additional Relevant MeSH Terms: Behavior; Motor Activity; Dietary Supplements; Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Prebiotics; Probiotics; Synbiotics
• Other Study ID Numbers: REB23-1161

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No