Immune Function and Intestinal MicrobiotaNCT02618005
Probiotics on Immune Function and Intestinal Microbiota in Astronauts Under Closed Microgravity Environment
A study testing Probiotic capsule in people with Immune Function and Intestinal Microbiota, run by Yakult Honsha Co., LTD at 1 site in Japan.
Trial summary
Human immune function and intestinal microbiota are suggested to be altered within long-duration stay in space. Accumulated evidences on earth support that Lacticaseibacillus paracasei strain Shirota (LcS) is a promising probiotic strain on improvement of immune function and intestinal microbiota. Read more about this study
- Who is it for?
- Ages 25 to 80 yearsHealthy volunteers can take part
- Conditions the study is for
- Immune Function and Intestinal Microbiota
- What is being tested?
- Probiotic capsule
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 10 participants
- Where
- 1 siteJapan
- Study dates
- Oct 2015to Apr 2022
- 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 25 to 80 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Individuals who are scheduled to stay on the ISS for at least 3 months
- Individuals who fully understand the study protocol and provide written informed consent for the study participation
Who cannot join
- Individuals who routinely use antibiotic, laxative, and/or bowel regulating medicine
- Individuals who participate in other research that competes with this study in terms of the purpose and field, e.g., study with dietary management or intake of bifidobacteria/lactic acid bacteria, oligosaccharides, antibiotic, laxative, and/or bowel regulating medicine
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Study for Evaluating the Impact of Continuous Consumption of Probiotics on Immune Function and Intestinal Microbiota in Astronauts Under Closed Microgravity Environment
Human immune function and intestinal microbiota are suggested to be altered within long-duration stay in space. Accumulated evidences on earth support that Lacticaseibacillus paracasei strain Shirota (LcS) is a promising probiotic strain on improvement of immune function and intestinal microbiota. This study aims to investigate the impact of long-duration spaceflight as well as intake of LcS on the international space station (ISS), on immune system and intestinal microbiota in astronauts.
- Being tested
- Probiotic capsule
- Keywords
- Astronauts, Probiotics, Immune function, Intestinal microbiota
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Probiotic capsuleDietary supplement
Continuously take five capsules containing freeze-dried LcS on ISS for four weeks, from four weeks before the return (R-4W) to one day before the return (R-1d)
| Study group | Role | What they receive |
|---|---|---|
| LcS group | Experimental | Consuming probiotic capsule Receives: Dietary Supplement: Probiotic capsule |
| Control group | No intervention | Not described |
What is being measured
The primary outcome is the main question the study is designed to answer.
Longitudinal changes in the number of LcS in feces
Number of LcS in feces will be assessed by PMA-qPCR, during pre-flight, in-flight and post-flight.
Measured: 9-18 months
Longitudinal changes in the level of immune markers
Levels of immune markers in blood/saliva will be assessed by ELISA and bioassay, during pre-flight, in-flight and post-flight.
Measured: 9-18 months
Longitudinal changes in numbers and composition of intestinal microbiota
Numbers and composition of bacteria in feces will be assessed by RT-qPCR/qPCR and next generation sequencer analysis, during pre-flight, in-flight and post-flight.
Measured: 9-18 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Dec 2015 (estimated)
- Study startOct 2015
- Primary completionApr 2022
- Study completionApr 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Immune Function and Intestinal MicrobiotaStudies 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 10 participants (actual)
Sponsor and investigators
- Lead sponsor
- Yakult Honsha Co., LTD
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Japan Aerospace Exploration Agency
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02618005
- Sponsor's protocol ID
- Probiotics
- Status last verified
- Nov 2025
- First submitted
- 1 Nov 2015
- Last updated
- 25 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 25 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Study for Evaluating the Impact of Continuous Consumption of Probiotics on Immune Function and Intestinal Microbiota in Astronauts Under Closed Microgravity Environment
- ClinicalTrials.gov ID
- NCT02618005
- Acronym / sponsor ID
- Probiotics
- Keywords
- Astronauts, Probiotics, Immune function, Intestinal microbiota
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 10 participants (actual)
- Lead sponsor
- Yakult Honsha Co., LTDIndustry (pharma, biotech, devices)
- Collaborators
- Japan Aerospace Exploration Agency
- Study start
- Oct 2015 (actual)
- Primary completion
- Apr 2022 (actual)
- Study completion
- Apr 2022 (actual)
- First posted
- 1 Dec 2015 (estimated)
- 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.
Human immune function and intestinal microbiota are suggested to be altered within long-duration stay in space. Accumulated evidences on earth support that Lacticaseibacillus paracasei strain Shirota (LcS) is a promising probiotic strain on improvement of immune function and intestinal microbiota. This study aims to investigate the impact of long-duration spaceflight as well as intake of LcS on the international space station (ISS), on immune system and intestinal microbiota in astronauts.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| LcS group | Experimental | Dietary Supplement: Probiotic capsuleConsuming probiotic capsule |
| Control group | No intervention | – |
Who may qualify
- Ages
- 25 to 80 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Individuals who are scheduled to stay on the ISS for at least 3 months
- Individuals who fully understand the study protocol and provide written informed consent for the study participation
Key exclusion criteria (2 listed)
- Individuals who routinely use antibiotic, laxative, and/or bowel regulating medicine
- Individuals who participate in other research that competes with this study in terms of the purpose and field, e.g., study with dietary management or intake of bifidobacteria/lactic acid bacteria, oligosaccharides, antibiotic, laxative, and/or bowel regulating medicine
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 |
|---|---|---|
| Probiotic capsuleContinuously take five capsules containing freeze-dried LcS on ISS for four weeks, from four weeks before the return (R-4W) to one day before the return (R-1d) | Dietary supplement | LcS group |
Primary outcome
Longitudinal changes in the number of LcS in feces
Time frame: 9-18 months
Number of LcS in feces will be assessed by PMA-qPCR, during pre-flight, in-flight and post-flight.
Longitudinal changes in the level of immune markers
Time frame: 9-18 months
Levels of immune markers in blood/saliva will be assessed by ELISA and bioassay, during pre-flight, in-flight and post-flight.
Longitudinal changes in numbers and composition of intestinal microbiota
Time frame: 9-18 months
Numbers and composition of bacteria in feces will be assessed by RT-qPCR/qPCR and next generation sequencer analysis, during pre-flight, in-flight and post-flight.
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 25 Nov 2025.
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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 Probiotic capsule in people with Immune Function and Intestinal Microbiota, run by Yakult Honsha Co., LTD at 1 site in Japan.
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 2 inclusion and 2 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 25 Nov 2025. 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 Japan. 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?
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?
Longitudinal changes in the number of LcS in feces (time frame: 9-18 months). The study lists 3 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 25 Nov 2025.