Respiratory Tract Infections (RTI)NCT06970964
Fermented Milk Drink With Lacticaseibacillus Paracasei Strain Shirota Helps Triathletes With Cold-Like Symptoms Before and After a Race
A study of Respiratory Tract Infections (RTI) and Mucosal Immunity, run by Federal University of São Paulo at 1 site in Brazil.
Trial summary
This study aims to evaluate whether a fermented milk drink containing the probiotic strain Lacticaseibacillus paracasei strain Shirota (LCS), commonly found in Yakult®, can help reduce upper respiratory symptoms in triathletes before and after competition. Read more about this study
- Who is it for?
- Ages 20 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Respiratory Tract Infections (RTI), Mucosal Immunity, Systemic Inflammation
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 80 participants
- Where
- 1 siteBrazil
- Study dates
- 13 Aug 2025to 5 Nov 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 20 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Aged between 20 and 60 years.
- Amateur triathletes with regular endurance training and prior competition experience.
- In good general health, with no history of chronic diseases or conditions affecting immune or inflammatory responses.
- Willing and able to comply with all study procedures, including sample collections and completion of validated questionnaires at five time points.
- Agree to consume a daily dose of fermented milk containing Lacticaseibacillus paracasei strain Shirota (LcS) or placebo from 30 days before until 14 days after the competition.
- No use of probiotics, antibiotics, or immunomodulatory supplements in the 30 days prior to enrollment
Who cannot join
- Known allergy or intolerance to dairy products, including lactose.
- Use of probiotics or antibiotics within 30 days prior to enrollment.
- Current use of any pharmacological treatment.
- History of chronic rhinopathy.
- Diagnosis of autoimmune disease.
- History of recurrent infections not involving the upper airway.
- Presence of major medical conditions or chronic diseases, including but not limited to respiratory or gastrointestinal disorders.
- Incomplete or missing data necessary for determining eligibility or for study outcomes.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Multi-Center, Double-Blind, Randomized, Parallel Group Study to Evaluate the Effect of Fermented Milk Containing Lacticaseibacillus Paracasei Strain Shirota (LCS) on the Upper Airway Symptoms of Triathletes Both Before and After a Competition
This study aims to evaluate whether a fermented milk drink containing the probiotic strain Lacticaseibacillus paracasei strain Shirota (LCS), commonly found in Yakult®, can help reduce upper respiratory symptoms in triathletes before and after competition.
Athletes often experience cold-like symptoms due to physical stress, intense training, and immune system challenges. The study investigates whether daily consumption of this probiotic drink can help improve immune response and reduce the incidence or severity of symptoms such as sore throat, nasal congestion, or coughing.
Read more
This is a randomized, double-blind, placebo-controlled, parallel-group study involving healthy adult triathletes. Participants will be randomly assigned to receive either the probiotic drink or a placebo for a specific period before and after a triathlon event. Symptoms and health markers will be tracked through questionnaires and biological samples.
The goal is to explore whether probiotic supplementation can provide practical, non-pharmacological support for athletes' immune health and well-being during intense physical activity.
Read the detailed description
Background:
Endurance athletes are frequently exposed to high physical stress, which may lead to temporary immune suppression and increased susceptibility to upper respiratory tract infections (URTIs). Previous studies suggest that probiotics may play a role in supporting the immune system.
Objective:
To assess the efficacy of a fermented milk drink containing Lacticaseibacillus paracasei strain Shirota (LCS) in reducing upper airway symptoms in triathletes before and after a competitive event.
Study Design:
This is a multi-center, double-blind, randomized, placebo-controlled, parallel-group study. Eligible participants will be healthy adult triathletes preparing for a scheduled race. They will be randomized to consume either the probiotic drink or a placebo daily, starting several weeks before the race and continuing for a defined recovery period afterward.
Primary Outcome:
-Salivary IgA Concentration The primary outcome is the change in salivary immunoglobulin A (IgA) concentration before and after the competition, assessed at five time points. This measure will reflect mucosal immune function and the potential modulatory effect of daily intake of fermented milk containing Lacticaseibacillus paracasei strain Shirota.
Secondary Outcomes:
- Systemic Immune and Inflammatory Response Blood samples will be analyzed for markers of systemic immune activation and inflammation (e.g., cytokines), collected at five time points to evaluate the broader immunomodulatory effects of the probiotic intervention.
- Upper Airway Symptoms Incidence, severity, and duration of upper airway symptoms (e.g., sore throat, cough, nasal congestion) will be assessed using the Wisconsin Upper Respiratory Symptom Survey-21 (WURSS-21). Higher scores indicate more severe symptoms and a greater impact on daily functioning.
- Mood State Mood state changes will be evaluated using the Brunel Mood Scale (BRUMS) across six subscales. Total Mood Disturbance (TMD) scores will reflect the psychological response to training and competition. Higher scores indicate worse mood states.
- Conditions
- Respiratory Tract Infections (RTI), Mucosal Immunity, Systemic Inflammation, Depressive Disorder, Exercise-Induced Immunosuppression, Athletic Performance
- Being tested
- Intervention Name: Fermented milk containing Lacticaseibacillus paracasei strain Shirota. Intervention Name: Non-fermented milk (placebo), Non-fermented milk (placebo)
- Keywords
- Immune Function, Sports Nutrition, Endurance Athletes, Lacticaseibacillus paracasei strain Shirota, Upper Respiratory Symptoms, Respiratory Tract Infections, Immunity, Mucosal, Inflammation, Probiotics, Exercise
- Medical subject headings
- Respiratory Tract Infections, Depressive Disorder, Psychological Well-Being, Signs and Symptoms, Respiratory, Inflammation, Motor Activity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Intervention Name: Fermented milk containing Lacticaseibacillus paracasei strain Shirota. Intervention Name: Non-fermented milk (placebo)Dietary supplement
Also called LcS, Lacticaseibacillus casei Shirota, Probiotic milk drink
Participants will ingest 80 mL per day of fermented milk containing 40 billion colony-forming units (CFU) of Lacticaseibacillus paracasei strain Shirota (LcS), starting 30 days before a triathlon competition and continuing until 14 days post-race. The fermented milk is stored refrigerated and consumed once daily.
Non-fermented milk (placebo)Dietary supplement
Also called Placebo milk
Participants will ingest 80 mL per day of non-fermented milk identical in taste, appearance, and packaging to the probiotic drink, but without Lacticaseibacillus paracasei strain Shirota. Administration follows the same schedule as the probiotic group.
| Study group | Role | What they receive |
|---|---|---|
| Probiotic | Experimental | Participants will receive one bottle per day of fermented milk containing 40 billion colony-forming units of Lacticaseibacillus paracasei strain Shirota (LcS) for 44 days.Intervention:
Type: Dietary Supplement Name: Lacticaseibacillus paracasei strain Shirota Description: Daily intake of fermented milk containing 40 billion CFU of LcS. Receives: Dietary Supplement: Intervention Name: Fermented milk containing Lacticaseibacillus paracasei strain Shirota. Intervention Name: Non-fermented milk (placebo) |
| Placebo Group | Placebo comparator | Name: Non-fermented milk Description: Daily intake of placebo (non-fermented milk) matched in appearance and taste to the probiotic. Receives: Dietary Supplement: Non-fermented milk (placebo) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Salivary IgA Concentration
The primary outcome measure is the change in salivary immunoglobulin A (IgA) concentration after daily intake of fermented milk containing Lacticaseibacillus paracasei strain Shirota. Saliva samples will be collected from participants at five time points: 30 days before the competition, 24 hours before, immediately after, 72 hours after, and 14 days post-competition. The concentration of salivary IgA will be measured to assess the impact of probiotic supplementation on immune function.
Measured: Pre-study: 30 days before the competition (baseline) During study: 24 hours before the competition Post-study: Immediately after the competition, 72 hours post-competition, and 14 days after the competition
Secondary outcomes (1)
Immune/Inflammatory Response
The secondary outcome measure is the assessment of systemic immune and inflammatory responses. Blood samples will be collected at five time points: 30 days before the competition, 24 hours before, immediately after, 72 hours after, and 14 days post-competition. These samples will be analyzed for markers of immune activation and inflammation to assess the effects of probiotic supplementation.
Measured: Pre-study: 30 days before the competition (baseline) During study: 24 hours before the competition Post-study: Immediately after the competition, 72 hours post-competition, and 14 days after the competition
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 May 2025
- Study start13 Aug 2025
- Primary completion21 Aug 2025
- Study completion5 Nov 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Respiratory Tract Infections (RTI)Studies of the same condition, open and under way.
- 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants will be randomly assigned to one of two parallel groups: one receiving fermented milk containing Lacticaseibacillus paracasei strain Shirota and the other receiving placebo (non-fermented milk).
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 80 participants (actual)
Sponsor and investigators
- Lead sponsor
- Federal University of São Paulo
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Jonatas Bussador do Amaral, Federal University of São Paulo
- Investigators
- Jonatas B do Amaral, PHD, Principal investigator, Federal University of São PauloAndré Luis L Bachi, PHD, Study chair, Universidade Santo AmaroCesar Miguel M dos Santos, PHD, Study chair, Enau CollegeMauro W Vaisberg, PHD, Study chair, Federal University of São Paulo
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06970964
- Sponsor's protocol ID
- 7.349.261
- Status last verified
- May 2025
- First submitted
- 30 Apr 2025
- Last updated
- 15 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Individual participant data (IPD) that underlie the results reported in the publication will be shared, after de-identification. This includes salivary IgA concentrations, data on immune and inflammatory markers, upper airway symptoms, and mood state scores (e.g., BRUMS questionnaire).
Publications
Vaisberg M, Paixao V, Almeida EB, Santos JMB, Foster R, Rossi M, Pithon-Curi TC, Gorjao R, Momesso CM, Andrade MS, Araujo JR, Garcia MC, Cohen M, Perez EC, Santos-Dias A, Vieira RP, Bachi ALL. Daily Intake of Fermented Milk Containing Lactobacillus casei Shirota (Lcs) Modulates Systemic and Upper Airways Immune/Inflammatory Responses in Marathon Runners. Nutrients. 2019 Jul 22;11(7):1678. doi: 10.3390/nu11071678.
PubMed 31336570
Study at a glance
From the registry record, last updated by the sponsor on 15 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Multi-Center, Double-Blind, Randomized, Parallel Group Study to Evaluate the Effect of Fermented Milk Containing Lacticaseibacillus Paracasei Strain Shirota (LCS) on the Upper Airway Symptoms of Triathletes Both Before and After a Competition
- ClinicalTrials.gov ID
- NCT06970964
- Acronym / sponsor ID
- 7.349.261
- Conditions
- Respiratory Tract Infections (RTI), Mucosal Immunity, Systemic Inflammation, Depressive Disorder, Exercise-Induced Immunosuppression, Athletic Performance
- Keywords
- Immune Function, Sports Nutrition, Endurance Athletes, Lacticaseibacillus paracasei strain Shirota, Upper Respiratory Symptoms, Respiratory Tract Infections, Immunity, Mucosal
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 80 participants (actual)
- Lead sponsor
- Federal University of São PauloUniversity, hospital or other
- Study start
- 13 Aug 2025 (actual)
- Primary completion
- 21 Aug 2025 (actual)
- Study completion
- 5 Nov 2025 (actual)
- First posted
- 14 May 2025 (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.
This study aims to evaluate whether a fermented milk drink containing the probiotic strain Lacticaseibacillus paracasei strain Shirota (LCS), commonly found in Yakult®, can help reduce upper respiratory symptoms in triathletes before and after competition.
Athletes often experience cold-like symptoms due to physical stress, intense training, and immune system challenges. The study investigates whether daily consumption of this probiotic drink can help improve immune response and reduce the incidence or severity of symptoms such as sore throat, nasal congestion, or coughing.
This is a randomized, double-blind, placebo-controlled, parallel-group study involving healthy adult triathletes. Participants will be randomly assigned to receive either the probiotic drink or a placebo for a specific period before and after a triathlon event. Symptoms and health markers will be tracked through questionnaires and biological samples.
The goal is to explore whether probiotic supplementation can provide practical, non-pharmacological support for athletes' immune health and well-being during intense physical activity.
Detailed description
Background:
Endurance athletes are frequently exposed to high physical stress, which may lead to temporary immune suppression and increased susceptibility to upper respiratory tract infections (URTIs). Previous studies suggest that probiotics may play a role in supporting the immune system.
Objective:
To assess the efficacy of a fermented milk drink containing Lacticaseibacillus paracasei strain Shirota (LCS) in reducing upper airway symptoms in triathletes before and after a competitive event.
Study Design:
This is a multi-center, double-blind, randomized, placebo-controlled, parallel-group study. Eligible participants will be healthy adult triathletes preparing for a scheduled race. They will be randomized to consume either the probiotic drink or a placebo daily, starting several weeks before the race and continuing for a defined recovery period afterward.
Primary Outcome:
-Salivary IgA Concentration The primary outcome is the change in salivary immunoglobulin A (IgA) concentration before and after the competition, assessed at five time points. This measure will reflect mucosal immune function and the potential modulatory effect of daily intake of fermented milk containing Lacticaseibacillus paracasei strain Shirota.
Secondary Outcomes:
- Systemic Immune and Inflammatory Response Blood samples will be analyzed for markers of systemic immune activation and inflammation (e.g., cytokines), collected at five time points to evaluate the broader immunomodulatory effects of the probiotic intervention.
- Upper Airway Symptoms Incidence, severity, and duration of upper airway symptoms (e.g., sore throat, cough, nasal congestion) will be assessed using the Wisconsin Upper Respiratory Symptom Survey-21 (WURSS-21). Higher scores indicate more severe symptoms and a greater impact on daily functioning.
- Mood State Mood state changes will be evaluated using the Brunel Mood Scale (BRUMS) across six subscales. Total Mood Disturbance (TMD) scores will reflect the psychological response to training and competition. Higher scores indicate worse mood states.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Participants will be randomly assigned to one of two parallel groups: one receiving fermented milk containing Lacticaseibacillus paracasei strain Shirota and the other receiving placebo (non-fermented milk).
| Arm | Type | Receives |
|---|---|---|
| Probiotic | Experimental | Dietary Supplement: Intervention Name: Fermented milk containing Lacticaseibacillus paracasei strain Shirota. Intervention Name: Non-fermented milk (placebo)Participants will receive one bottle per day of fermented milk containing 40 billion colony-forming units of Lacticaseibacillus paracasei strain Shirota (LcS) for 44 days.Intervention: Type: Dietary Supplement Name: Lacticaseibacillus paracasei strain Shirota Description: Daily intake of fermented milk containing 40 billion CFU of LcS. |
| Placebo Group | Placebo comparator | Dietary Supplement: Non-fermented milk (placebo)Name: Non-fermented milk Description: Daily intake of placebo (non-fermented milk) matched in appearance and taste to the probiotic. |
Who may qualify
- Ages
- 20 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Aged between 20 and 60 years.
- Amateur triathletes with regular endurance training and prior competition experience.
- In good general health, with no history of chronic diseases or conditions affecting immune or inflammatory responses.
- Willing and able to comply with all study procedures, including sample collections and completion of validated questionnaires at five time points.
- Agree to consume a daily dose of fermented milk containing Lacticaseibacillus paracasei strain Shirota (LcS) or placebo from 30 days before until 14 days after the competition.
Key exclusion criteria (8 listed)
- Known allergy or intolerance to dairy products, including lactose.
- Use of probiotics or antibiotics within 30 days prior to enrollment.
- Current use of any pharmacological treatment.
- History of chronic rhinopathy.
- Diagnosis of autoimmune disease.
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 |
|---|---|---|
| Intervention Name: Fermented milk containing Lacticaseibacillus paracasei strain Shirota. Intervention Name: Non-fermented milk (placebo)Also: LcS, Lacticaseibacillus casei Shirota, Probiotic milk drinkParticipants will ingest 80 mL per day of fermented milk containing 40 billion colony-forming units (CFU) of Lacticaseibacillus paracasei strain Shirota (LcS), starting 30 days before a triathlon competition and continuing until 14 days post-race. The fermented milk is stored refrigerated and consumed once daily. | Dietary supplement | Probiotic |
| Non-fermented milk (placebo)Also: Placebo milkParticipants will ingest 80 mL per day of non-fermented milk identical in taste, appearance, and packaging to the probiotic drink, but without Lacticaseibacillus paracasei strain Shirota. Administration follows the same schedule as the probiotic group. | Dietary supplement | Placebo Group |
Primary outcome
Salivary IgA Concentration
Time frame: Pre-study: 30 days before the competition (baseline) During study: 24 hours before the competition Post-study: Immediately after the competition, 72 hours post-competition, and 14 days after the competition
The primary outcome measure is the change in salivary immunoglobulin A (IgA) concentration after daily intake of fermented milk containing Lacticaseibacillus paracasei strain Shirota. Saliva samples will be collected from participants at five time points: 30 days before the competition, 24 hours before, immediately after, 72 hours after, and 14 days post-competition. The concentration of salivary IgA will be measured to assess the impact of probiotic supplementation on immune function.
1 secondary outcome
Immune/Inflammatory Response
Time frame: Pre-study: 30 days before the competition (baseline) During study: 24 hours before the competition Post-study: Immediately after the competition, 72 hours post-competition, and 14 days after the competition
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Oct 2026.
- Background: PubMed 31336570Vaisberg M, Paixao V, Almeida EB, Santos JMB, Foster R, Rossi M, Pithon-Curi TC, Gorjao R, Momesso CM, Andrade MS, Araujo JR, Garcia MC, Cohen M, Perez EC, Santos-Dias A, Vieira RP, Bachi ALL. Daily Intake of Fermented Milk Containing Lactobacillus casei Shirota (Lcs) Modulates Systemic and Upper Airways Immune/Inflammatory Responses in Marathon Runners. Nutrients. 2019 Jul 22;11(7):1678. doi: 10.3390/nu11071678.
- instagram ORL LAB pageLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. Individual participant data (IPD) that underlie the results reported in the publication will be shared, after de-identification. This includes salivary IgA concentrations, data on immune and inflammatory markers, upper airway symptoms, and mood state scores (e.g., BRUMS questionnaire).
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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.
Jonatas B do Amaral, PHD principal investigator
Federal University of São Paulo
André Luis L Bachi, PHD study chair
Universidade Santo Amaro
Cesar Miguel M dos Santos, PHD study chair
Enau College
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study of Respiratory Tract Infections (RTI) and Mucosal Immunity, run by Federal University of São Paulo at 1 site in Brazil.
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 6 inclusion and 8 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: finished, as of the sponsor's last update on 15 Oct 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 Brazil. 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. Some participants in this study may receive a placebo. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Salivary IgA Concentration (time frame: Pre-study: 30 days before the competition (baseline) During study: 24 hours before the competition Post-study: Immediately after the competition, 72 hours post-competition, and 14 days after the competition). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06970964, which also lists 1 linked publication.
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 15 Oct 2026; AzTrials last refreshed its copy on 26 Oct 2026.