Intestinal MicrobiomePreludiumKPNCT07411482
The Effect of Probiotic Supplementation on the Exercise Performance of Long-distance Runners.
A study testing Box diet in people with Intestinal Microbiome and Probiotic, run by Medical University of Gdansk at 1 site in Poland.
Trial summary
The study is designed as a randomized double-blind placebo-controlled clinical trial with a 4-week probiotics intervention period. The study will be conducted between January 2022 and March 2025 at the Medical University of Gdańsk, Department of Bioenergetics and Physiology of Exercise (Gdańsk, Poland). Read more about this study
- Who is it for?
- Ages 18 to 45 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Intestinal Microbiome, Probiotic, Runners
- What is being tested?
- Box diet
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 27 participants
- Where
- 1 sitePoland
- Study dates
- 1 Dec 2023to Mar 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Endurance-trained adult men (aged ≥ 18 years)
- Long-distance runners with experience in at least three marathons or half-marathons
- Average running speed between 10.549 and 14.065 km/h
- At least 3 years of regular endurance training experience
- Completion of 5 or more training sessions per week
Who cannot join
- Age below 18 years
- Female gender
- Antibiotic therapy within the last 3 months
- Diagnosed inflammatory bowel disease
- Chronic musculoskeletal injuries within the last 6 months
- Heart failure or heart defects
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Impact of the Gut Microbiome on Intestinal Mucosal Function and Exercise Performance in Marathon Runners.
The study is designed as a randomized double-blind placebo-controlled clinical trial with a 4-week probiotics intervention period. The study will be conducted between January 2022 and March 2025 at the Medical University of Gdańsk, Department of Bioenergetics and Physiology of Exercise (Gdańsk, Poland). A total of 40 endurance-trained adult men, specifically long-distance runners with previous experience in marathon races, will be enrolled. Only participants who meet all inclusion criteria and do not meet any exclusion criteria will be included in the study. Participants will be randomly assigned to the probiotic (PRO) or placebo (PL) group in a 1:1 ratio. Athletes will supplement 4 capsules of the study product (probiotic mixture) daily.
To eliminate the effect of diet on the gut microbiome, all athletes will receive an individually balanced box diet designed to provide 100% of energy requirements, protein intake of 1.6 g/kg/day, and at least 8 g/kg/day of carbohydrates. Participants will continue their training programs and perform at least 5 endurance workouts per week. To assess training loads, athletes will report average pulse range, subjective fatigue, and duration of training sessions.
Read more
The investigators will examine whether 4 weeks of probiotic supplementation in conjunction with a personalized diet may have a direct or indirect influence on sport performance. This will be assessed through evaluation of aerobic fitness capacity using treadmill tests. The cardiopulmonary exercise test (CPET) will determine maximum oxygen uptake, minute lung ventilation, and heart rate. Body composition analysis and assessments of blood and fecal samples will also be performed. Blood samples will be analyzed for serum pro-inflammatory cytokines (IL-6 and TNF-α). Collected fecal samples will be subjected to quantitative and qualitative analysis of the intestinal microbiota using next-generation sequencing. The analysis will include intestinal permeability markers (calprotectin, zonulin, IFABP) and bacterial metabolism products such as short-chain fatty acids (SCFA). All assessments and procedures will be carried out both before and immediately after the supplementation period.
All obtained data will undergo statistical analysis. Descriptive statistics will be used for background information and to examine trends in the analyzed parameters, with mean values and 95% confidence intervals. Depending on the distribution of the data, parametric or non-parametric tests will be applied. Statistical significance will be set at p < 0.05.
To the best of the investigators' knowledge, this will be the first intervention study comprehensively assessing the influence of probiotic supplementation in conjunction with a standardized diet on inflammatory response, intestinal permeability, gut microbiome composition, and aerobic capacity of competitive long-distance runners. The collected data will provide evidence regarding the potential influence of probiotic supplementation on parameters of sport performance.
- Conditions
- Intestinal Microbiome, Probiotic, Runners
- Being tested
- probiotics or placebo, Box diet
- Keywords
- Probiotisc, athletes, runners, intestinal mucosal unction
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
probiotics or placeboDietary supplement
The study product is a probiotic mixture Sanprobi Active \& Sport, containing 2,5 x 109 CFU/g per capsule (≥500 million CFU in one capsule) of five strains of lactic acid bacteria (Bifidobacterium lactis W51, Lactobacillus brevis W63, Lactobacillus acidophilus W22, Bifidobacterium bifidum W23 and Lactococcus lactis W5); maize starch, maltodextrin, plant proteins and hydroxypropyl ethylcellulose tablets' coating.
OR PLACEBo identically-looked
Box dietDietary supplement
Also called GroupA
To eliminate the effect of diet on the gut microbiome, all athletes received optimal, individually-balanced box-diet.
| Study group | Role | What they receive |
|---|---|---|
| A | Experimental | Participants who supplement probiotics or placebo Receives: Dietary Supplement: probiotics or placebo; Dietary Supplement: Box diet |
| B | Experimental | Participants who supplement probiotics or placebo Receives: Dietary Supplement: probiotics or placebo; Dietary Supplement: Box diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
The assessment of the impact of probiotic supplementation on maximal oxygen uptake value among athletes.
Aerobic capacity will be assessed using an incremental treadmill test performed to volitional exhaustion. After a brief standing period on the treadmill to ensure stabilization of the measurement equipment, participants will complete a standardized low-intensity warm-up, followed by a stepwise increase in exercise intensity until exhaustion. Heart rate will be continuously monitored (Polar Electro Oy, Kempele, Finland), and respiratory variables (VO₂, VCO₂, VE, and RER) will be measured breath-by-breath using a calibrated metabolic cart (Oxycon Pro, Jaeger, Germany). Peak oxygen uptake (VO₂peak) will be defined as the highest value recorded during the test.
Measured: Baseline visit (before supplementation period) and after 4 weeks of supplementation period (post-intervention).
Analysis of gut microbiome
Fecal samples will be collected by participants before and after the 4-week intervention period using standardized containers. Samples will be immediately frozen at -80°C and analyzed by an independent laboratory. The intestinal microbiota will be assessed using next-generation sequencing of selected 16S rRNA gene regions. Microbiome composition will be characterized by alpha diversity (Chao1, ACE, Shannon, inverted Simpson) and beta diversity (Bray-Curtis and weighted UniFrac), and analyzed in relation to intestinal permeability markers (calprotectin, zonulin, IFABP) and bacterial metabolites (short-chain fatty acids, SCFA).
Measured: Baseline (pre-intervention) and after 4 weeks of supplementation (post-intervention).
Secondary outcomes (1)
Assessment of inflammatroy state
The blood samples will be collected during sport test at the two points time: PRE and POST intervention, at the same conditions. Blood samples from the arm vein will be drawn by a specialist nurse into appropriate standardized tubes containing clotting activator. Each time up to 4 ml of blood will be collected. Blood samples will be taken indirectly before the start of exercise tests and 30 minutes after the end of the tests. The blood will then be centrifuged at 3000 x g to separate serum. The material will be placed into separately labeled microcentrifuge tubes and stored at -80 ° C for later determinations.
We assess the level of serum pro-inflammatory cytokines (IL-6 and TNF-α) using a commercially available enzyme-linked immunosorbent assay (ELISA) kits.
Measured: Baseline (pre-supplementation) and after 4 weeks of supplementation (post-intervention), with blood samples collected immediately before exercise and 30 minutes after the exercise test.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Feb 2026
- Study start1 Dec 2023
- Primary completionMar 2026 (estimated)
- Study completionMar 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Intestinal MicrobiomeStudies of the same condition, open and under way.
- More trials run by Medical University of GdanskThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- double-blinded placebo controlled trial
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 27 participants (actual)
Sponsor and investigators
- Lead sponsor
- Medical University of Gdansk
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Katarzyna Przewłócka, Medical University of Gdansk
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07411482
- Sponsor's protocol ID
- Runners2023
- Other IDs
- 2021/41/N/NZ4/02364
- Acronym
- PreludiumKP
- Status last verified
- Feb 2026
- First submitted
- 31 Dec 2025
- Last updated
- 13 Feb 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 13 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Impact of the Gut Microbiome on Intestinal Mucosal Function and Exercise Performance in Marathon Runners.
- ClinicalTrials.gov ID
- NCT07411482
- Acronym / sponsor ID
- PreludiumKP / Runners2023
- Conditions
- Intestinal Microbiome, Probiotic, Runners
- Keywords
- Probiotisc, athletes, runners, intestinal mucosal unction
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 27 participants (actual)
- Lead sponsor
- Medical University of GdanskUniversity, hospital or other
- Study start
- 1 Dec 2023 (actual)
- Primary completion
- Mar 2026 (estimated)
- Study completion
- Mar 2026 (estimated)
- First posted
- 13 Feb 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The study is designed as a randomized double-blind placebo-controlled clinical trial with a 4-week probiotics intervention period. The study will be conducted between January 2022 and March 2025 at the Medical University of Gdańsk, Department of Bioenergetics and Physiology of Exercise (Gdańsk, Poland). A total of 40 endurance-trained adult men, specifically long-distance runners with previous experience in marathon races, will be enrolled. Only participants who meet all inclusion criteria and do not meet any exclusion criteria will be included in the study. Participants will be randomly assigned to the probiotic (PRO) or placebo (PL) group in a 1:1 ratio. Athletes will supplement 4 capsules of the study product (probiotic mixture) daily.
To eliminate the effect of diet on the gut microbiome, all athletes will receive an individually balanced box diet designed to provide 100% of energy requirements, protein intake of 1.6 g/kg/day, and at least 8 g/kg/day of carbohydrates. Participants will continue their training programs and perform at least 5 endurance workouts per week. To assess training loads, athletes will report average pulse range, subjective fatigue, and duration of training sessions.
The investigators will examine whether 4 weeks of probiotic supplementation in conjunction with a personalized diet may have a direct or indirect influence on sport performance. This will be assessed through evaluation of aerobic fitness capacity using treadmill tests. The cardiopulmonary exercise test (CPET) will determine maximum oxygen uptake, minute lung ventilation, and heart rate. Body composition analysis and assessments of blood and fecal samples will also be performed. Blood samples will be analyzed for serum pro-inflammatory cytokines (IL-6 and TNF-α). Collected fecal samples will be subjected to quantitative and qualitative analysis of the intestinal microbiota using next-generation sequencing. The analysis will include intestinal permeability markers (calprotectin, zonulin, IFABP) and bacterial metabolism products such as short-chain fatty acids (SCFA). All assessments and procedures will be carried out both before and immediately after the supplementation period.
All obtained data will undergo statistical analysis. Descriptive statistics will be used for background information and to examine trends in the analyzed parameters, with mean values and 95% confidence intervals. Depending on the distribution of the data, parametric or non-parametric tests will be applied. Statistical significance will be set at p < 0.05.
To the best of the investigators' knowledge, this will be the first intervention study comprehensively assessing the influence of probiotic supplementation in conjunction with a standardized diet on inflammatory response, intestinal permeability, gut microbiome composition, and aerobic capacity of competitive long-distance runners. The collected data will provide evidence regarding the potential influence of probiotic supplementation on parameters of sport performance.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- double-blinded placebo controlled trial
| Arm | Type | Receives |
|---|---|---|
| A | Experimental | Dietary Supplement: probiotics or placebo, Dietary Supplement: Box dietParticipants who supplement probiotics or placebo |
| B | Experimental | Dietary Supplement: probiotics or placebo, Dietary Supplement: Box dietParticipants who supplement probiotics or placebo |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Endurance-trained adult men (aged ≥ 18 years)
- Long-distance runners with experience in at least three marathons or half-marathons
- Average running speed between 10.549 and 14.065 km/h
- At least 3 years of regular endurance training experience
- Completion of 5 or more training sessions per week
Key exclusion criteria (6 listed)
- Age below 18 years
- Female gender
- Antibiotic therapy within the last 3 months
- Diagnosed inflammatory bowel disease
- Chronic musculoskeletal injuries within the last 6 months
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| probiotics or placeboThe study product is a probiotic mixture Sanprobi Active \& Sport, containing 2,5 x 109 CFU/g per capsule (≥500 million CFU in one capsule) of five strains of lactic acid bacteria (Bifidobacterium lactis W51, Lactobacillus brevis W63, Lactobacillus acidophilus W22, Bifidobacterium bifidum W23 and Lactococcus lactis W5); maize starch, maltodextrin, plant proteins and hydroxypropyl ethylcellulose tablets' coating. OR PLACEBo identically-looked | Dietary supplement | A, B |
| Box dietAlso: GroupATo eliminate the effect of diet on the gut microbiome, all athletes received optimal, individually-balanced box-diet. | Dietary supplement | A, B |
Primary outcome
The assessment of the impact of probiotic supplementation on maximal oxygen uptake value among athletes.
Time frame: Baseline visit (before supplementation period) and after 4 weeks of supplementation period (post-intervention).
Aerobic capacity will be assessed using an incremental treadmill test performed to volitional exhaustion. After a brief standing period on the treadmill to ensure stabilization of the measurement equipment, participants will complete a standardized low-intensity warm-up, followed by a stepwise increase in exercise intensity until exhaustion. Heart rate will be continuously monitored (Polar Electro Oy, Kempele, Finland), and respiratory variables (VO₂, VCO₂, VE, and RER) will be measured breath-by-breath using a calibrated metabolic cart (Oxycon Pro, Jaeger, Germany). Peak oxygen uptake (VO₂peak) will be defined as the highest value recorded during the test.
Analysis of gut microbiome
Time frame: Baseline (pre-intervention) and after 4 weeks of supplementation (post-intervention).
Fecal samples will be collected by participants before and after the 4-week intervention period using standardized containers. Samples will be immediately frozen at -80°C and analyzed by an independent laboratory. The intestinal microbiota will be assessed using next-generation sequencing of selected 16S rRNA gene regions. Microbiome composition will be characterized by alpha diversity (Chao1, ACE, Shannon, inverted Simpson) and beta diversity (Bray-Curtis and weighted UniFrac), and analyzed in relation to intestinal permeability markers (calprotectin, zonulin, IFABP) and bacterial metabolites (short-chain fatty acids, SCFA).
1 secondary outcome
Assessment of inflammatroy state
Time frame: Baseline (pre-supplementation) and after 4 weeks of supplementation (post-intervention), with blood samples collected immediately before exercise and 30 minutes after the exercise test.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Feb 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Box diet in people with Intestinal Microbiome and Probiotic, run by Medical University of Gdansk at 1 site in Poland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 13 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Poland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The assessment of the impact of probiotic supplementation on maximal oxygen uptake value among athletes. (time frame: Baseline visit (before supplementation period) and after 4 weeks of supplementation period (post-intervention).). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Feb 2026.