EmotionKefirnessNCT07522372
Evaluation of the Effect of Kefir Consumption
An observational study of Emotion and Well-being, run by Sys2Diag at 1 site in France.
Trial summary
Many societies traditionally use fermentation as a means of producing beverages, whose microbial transformation is spontaneously triggered or facilitated by the addition of a catalyst (yeasts, bacteria). Kefir is a traditional beverage belonging to the latter category. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Emotion, Well-being
- What is being tested?
- Consumption of fruit kefir and Consumption of micro-filtered fruit kefir
- How many people
- 66 participants
- Where
- 1 siteFrance
- Study dates
- 4 Jun 2024to 11 Jun 2027
- Phase
- Observational
- 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 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: A total of 66 subjects will be recruited on a voluntary basis : * 22 subjects who will consume a control beverage, non-fermented carbonated drink (BRAS-C) * 22 subjects who will consume fruit kefir (BRAS-F) * 22 subjects who will consume micro-filtered fruit kefir (BRAS-P). The distribution of subjects into the 3 BRAS will be carried out by a controlled randomized method.
Who may be able to join
- Subject aged between 18 and 65 years
- Subject agreeing to follow the study procedures
- Subject capable of understanding the purpose, nature, and methodology of the study
- Subject having signed the informed consent
- Subject who has never regularly consumed kefir and/or kombucha.
Who cannot join
- Pregnant or breastfeeding woman
- Subject not affiliated with a French Social Security scheme or not a beneficiary of such a scheme
- Subject deprived of liberty, protected adults, vulnerable persons, or minors
- Refusal to sign the consent to participate in the research
- Subject who has already regularly consumed kefir and/or kombucha
- Subject with confirmed diabetes
Show all 10Show fewer
- Criteria for Discontinuation of Participation in the Research :
- Withdrawal of consent to participate in the research
- Investigator's decision
- Occurrence of a non-inclusion criterion.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Evaluation of the Effect of Kefir Consumption on Urinary and Salivary Levels of Metabolites Such as BCAAs and on Biomarkers of Well-being
Many societies traditionally use fermentation as a means of producing beverages, whose microbial transformation is spontaneously triggered or facilitated by the addition of a catalyst (yeasts, bacteria). Kefir is a traditional beverage belonging to the latter category.
It is a probiotic that is supposed to modify the intestinal microbiota and the metabolites produced.
Links between kefir and metabolic syndromes (insulin resistance, etc.) have also been described in animal models. Very few clinical studies have evaluated the effects of kefir in humans.
A 'positive feeling' has also been described by people who consume kefir. Kefir could therefore have an effect on people's well-being.
Read the detailed description
Many societies traditionally use fermentation as a means of producing beverages, whose microbial transformation is spontaneously triggered or facilitated by the addition of a catalyst (yeasts, bacteria). Kefir is a traditional beverage belonging to the latter category. This beverage is obtained by inoculating sugared water, supplemented with fresh and dried fruits, with translucent grains composed of symbiotic microorganism communities (mainly lactic acid bacteria and yeasts). Kefir conveys an image of a 'healthy' beverage, naturally sparkling and non-alcoholic (alcohol content <1%), rich in probiotics), which undoubtedly explains the enthusiasm it generates among consumers.
The traditional nature of kefir lies in the use of fresh kefir grains as the sole ferment, passed down from producer to producer over generations.
Kefir is a probiotic that is supposed to modify the intestinal microbiota and the metabolites produced. Recent studies have described positive health effects of kefir. These effects could be exerted by a combination of live microorganisms contained in the fermented beverage, as well as by the bioactive components released in foods as by-products of the fermentation process. Links between kefir and metabolic syndromes (insulin resistance, etc.) have also been described in animal models. Very few clinical studies have evaluated the effects of kefir in humans. Branched-chain amino acids (BCAAs) are provided by the diet and are essential to the human body. They are also markers of insulin resistance. Measuring metabolites such as BCAAs in biofluids would verify if kefir has an effect on food degradation and thus on the intake of essential amino acids. This information is important both to better understand the mechanism of action of kefir and its effects on the production of metabolites such as BCAAs.
- Conditions
- Emotion, Well-being
- Being tested
- Consumption of a control beverage, non-fermented carbonated drink, Consumption of fruit kefir, Consumption of micro-filtered fruit kefir
- Keywords
- Biomarkers, Related, Probiotic, Kefir
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Consumption of a control beverage, non-fermented carbonated drinkOther
Consumption of a control beverage, non-fermented carbonated drink and measurement of the concentrations of metabolites such as BCAAs (valine, leucine, and isoleucine) in the biofluids (urine and saliva) of subjects, before and after regular consumption of fruit kefir.
Consumption of fruit kefirOther
Consumption of fruit kefir and measurement of the concentrations of metabolites such as BCAAs (valine, leucine, and isoleucine) in the biofluids (urine and saliva) of subjects, before and after regular consumption of fruit kefir.
Consumption of micro-filtered fruit kefirOther
Consumption of micro-filtered fruit kefir and measurement of the concentrations of metabolites such as BCAAs (valine, leucine, and isoleucine) in the biofluids (urine and saliva) of subjects, before and after regular consumption of fruit kefir.
| Study group | Role | What they receive |
|---|---|---|
| BRAS-C | Consumption of a control beverage, non-fermented carbonated drink Receives: Other: Consumption of a control beverage, non-fermented carbonated drink | |
| BRAS-F | Consumption of fruit kefir Receives: Other: Consumption of fruit kefir | |
| BRAS-P | Consumption of micro-filtered fruit kefir Receives: Other: Consumption of micro-filtered fruit kefir |
What is being measured
The primary outcome is the main question the study is designed to answer.
Evaluate the effects of fruit kefir
Evaluate the effects of fruit kefir on the release of amino acids such as BCAAs and more generally of metabolites in human biofluids (urine and saliva).
The measurement of the concentrations of metabolites such as BCAAs (valine, leucine, and isoleucine) carried out in the biofluids (urine and saliva) of subjects, before and after regular consumption of fruit kefir using IDIR enzymatic dosage kit for BCAAs in a urine sample (SkillCell, France) according to the supplier's instructions. The concentrations are expressed in µM.
Measured: 3 years
Secondary outcomes (6)
Evaluate the effects of kefir on the well-being of participants
Evaluate the effects of kefir on the well-being of participants who regularly consume this beverage, by measuring molecular biomarkers linked to the emotions felt. The levels of four biomarkers of interest (cortisol, alpha-amylase, DHEA, and oxytocin) will be measured in the saliva of participating subjects using enzymatic dosage methods or ELISA-type methods carried out using commercial kits. Concentrations are expressed in pM for cortisol and oxytocin, in U/mL for alpha-amylase, and in nM for DHEA.
Measured: 3 years
Compare the signatures of these molecular biomarkers in the saliva of subjects who consume different types of kefir preparations and subjects who consume a non-alcoholic carbonated placebo beverage
The comparison of the signatures of the biomarkers (cortisol, DHEA, oxytocin abd lapha amylase) in the saliva of subjects who consume fruit kefir, micro-filtered fruit kefir, or a non-alcoholic carbonated control beverage. Saliva samples are collected before and after consuming kefir. The baseline concentrations of biomarkers observed prior to kefir consumption revealed relatively high inter-individual variability. To account for the above and differing units of measurement, biomarker values are expressed as ratios following kefir consumption relative to the baseline value (prior to kefir consumption), thereby enabling comparisons on a consistent scale. Emotional assessments will be performed using a questionnaire.
The variation profiles of the four biomarkers will be associated to emotional profiles induced by the drinks.
Measured: 3 years
Compare the rate of BCAAs in the urine and saliva
Compare the rate of BCAAs in the urine and saliva of subjects who consume different types of kefir preparations and subjects who consume a non-alcoholic carbonated placebo beverage.
Measured: 3 years
Establish a correlation between the rate of BCAAs and the molecular signature established
Establish a correlation between the rate of BCAAs and the molecular signature established from the dosage of biological biomarkers linked to emotions.
Measured: 3 years
Establish a correlation between the metabolic changes measured with the rate of BCAAs
Establish a correlation between the metabolic changes measured with the rate of BCAAs and the evaluation of the feelings of consumers according to other criteria such as questionnaires (self-assessment) for example.
Measured: 3 years
Establish a correlation between the molecular signature established from the dosage
Establish a correlation between the molecular signature established from the dosage of biological biomarkers of emotions and the evaluation of the well-being of consumers according to other criteria such as questionnaires (self-assessment) for example.
Measured: 3 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Apr 2026
- Study start4 Jun 2024
- Primary completion11 Jun 2025
- Study completion11 Jun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for EmotionStudies 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 66 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Sys2Diag
- Sponsor type
- Other government
- Collaborators
- Centre National de la Recherche Scientifique, France
- Responsible party
- Principal investigator, Laurence MOLINA, Sys2Diag
- Investigators
- Laurence MOLINA, PhD, Principal investigator, Sys2Diag
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07522372
- Sponsor's protocol ID
- 2023-A02587-38
- Other IDs
- 24.00472.000223
- Acronym
- Kefirness
- Status last verified
- Apr 2026
- First submitted
- 26 Mar 2026
- Last updated
- 13 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Renaud Debailly, Christophe Lavelle et Émilien Schultz, " Conserver un aliment vivant ", Techniques & Culture, 69 | 2018, URL : http://journals.openedition.org/tc/8971
Laureys D, De Vuyst L. Microbial species diversity, community dynamics, and metabolite kinetics of water kefir fermentation. Appl Environ Microbiol. 2014 Apr;80(8):2564-72. doi: 10.1128/AEM.03978-13. Epub 2014 Feb 14.
PubMed 24532061Molina L, Santos Schneider F, Kahli M, Ouedraogo A, Alali M, Almosnino A, Baptiste J, Boulestreau J, Davy M, Houot-Cernettig J, Mountou T, Quenot M, Simphor E, Petit V, Molina F. Capturing Emotions Induced by Fragrances in Saliva: Objective Emotional Assessment Based on Molecular Biomarker Profiles. Biosensors (Basel). 2026 Jan 28;16(2):81. doi: 10.3390/bios16020081.
PubMed 41744700Pendon MD, Bengoa AA, Iraporda C, Medrano M, Garrote GL, Abraham AG. Water kefir: Factors affecting grain growth and health-promoting properties of the fermented beverage. J Appl Microbiol. 2022 Jul;133(1):162-180. doi: 10.1111/jam.15385. Epub 2021 Dec 20.
PubMed 34822204Lopitz-Otsoa F, Rementeria A, Elguezabal N, Garaizar J. Kefir: a symbiotic yeasts-bacteria community with alleged healthy capabilities. Rev Iberoam Micol. 2006 Jun;23(2):67-74. doi: 10.1016/s1130-1406(06)70016-x.
PubMed 16854180
Study at a glance
From the registry record, last updated by the sponsor on 13 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of the Effect of Kefir Consumption on Urinary and Salivary Levels of Metabolites Such as BCAAs and on Biomarkers of Well-being
- ClinicalTrials.gov ID
- NCT07522372
- Acronym / sponsor ID
- Kefirness / 2023-A02587-38
- Conditions
- Emotion, Well-being
- Keywords
- Biomarkers, Related, Probiotic, Kefir
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 66 participants (estimated)
- Lead sponsor
- Sys2DiagOther government
- Collaborators
- Centre National de la Recherche Scientifique, France
- Study start
- 4 Jun 2024 (actual)
- Primary completion
- 11 Jun 2025 (actual)
- Study completion
- 11 Jun 2027 (estimated)
- First posted
- 13 Apr 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.
Many societies traditionally use fermentation as a means of producing beverages, whose microbial transformation is spontaneously triggered or facilitated by the addition of a catalyst (yeasts, bacteria). Kefir is a traditional beverage belonging to the latter category.
It is a probiotic that is supposed to modify the intestinal microbiota and the metabolites produced.
Links between kefir and metabolic syndromes (insulin resistance, etc.) have also been described in animal models. Very few clinical studies have evaluated the effects of kefir in humans.
A 'positive feeling' has also been described by people who consume kefir. Kefir could therefore have an effect on people's well-being.
Detailed description
Many societies traditionally use fermentation as a means of producing beverages, whose microbial transformation is spontaneously triggered or facilitated by the addition of a catalyst (yeasts, bacteria). Kefir is a traditional beverage belonging to the latter category. This beverage is obtained by inoculating sugared water, supplemented with fresh and dried fruits, with translucent grains composed of symbiotic microorganism communities (mainly lactic acid bacteria and yeasts). Kefir conveys an image of a 'healthy' beverage, naturally sparkling and non-alcoholic (alcohol content <1%), rich in probiotics), which undoubtedly explains the enthusiasm it generates among consumers.
The traditional nature of kefir lies in the use of fresh kefir grains as the sole ferment, passed down from producer to producer over generations.
Kefir is a probiotic that is supposed to modify the intestinal microbiota and the metabolites produced. Recent studies have described positive health effects of kefir. These effects could be exerted by a combination of live microorganisms contained in the fermented beverage, as well as by the bioactive components released in foods as by-products of the fermentation process. Links between kefir and metabolic syndromes (insulin resistance, etc.) have also been described in animal models. Very few clinical studies have evaluated the effects of kefir in humans. Branched-chain amino acids (BCAAs) are provided by the diet and are essential to the human body. They are also markers of insulin resistance. Measuring metabolites such as BCAAs in biofluids would verify if kefir has an effect on food degradation and thus on the intake of essential amino acids. This information is important both to better understand the mechanism of action of kefir and its effects on the production of metabolites such as BCAAs.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| BRAS-C | – | Other: Consumption of a control beverage, non-fermented carbonated drinkConsumption of a control beverage, non-fermented carbonated drink |
| BRAS-F | – | Other: Consumption of fruit kefirConsumption of fruit kefir |
| BRAS-P | – | Other: Consumption of micro-filtered fruit kefirConsumption of micro-filtered fruit kefir |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- A total of 66 subjects will be recruited on a voluntary basis : * 22 subjects who will consume a control beverage, non-fermented carbonated drink (BRAS-C) * 22 subjects who will consume fruit kefir (BRAS-F) * 22 subjects who will consume micro-filtered fruit kefir (BRAS-P). The distribution of subjects into the 3 BRAS will be carried out by a controlled randomized method.
Key inclusion criteria (5 listed)
- Subject aged between 18 and 65 years
- Subject agreeing to follow the study procedures
- Subject capable of understanding the purpose, nature, and methodology of the study
- Subject having signed the informed consent
- Subject who has never regularly consumed kefir and/or kombucha.
Key exclusion criteria (10 listed)
- Pregnant or breastfeeding woman
- Subject not affiliated with a French Social Security scheme or not a beneficiary of such a scheme
- Subject deprived of liberty, protected adults, vulnerable persons, or minors
- Refusal to sign the consent to participate in the research
- Subject who has already regularly consumed kefir and/or kombucha
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 |
|---|---|---|
| Consumption of a control beverage, non-fermented carbonated drinkConsumption of a control beverage, non-fermented carbonated drink and measurement of the concentrations of metabolites such as BCAAs (valine, leucine, and isoleucine) in the biofluids (urine and saliva) of subjects, before and after regular consumption of fruit kefir. | Other | BRAS-C |
| Consumption of fruit kefirConsumption of fruit kefir and measurement of the concentrations of metabolites such as BCAAs (valine, leucine, and isoleucine) in the biofluids (urine and saliva) of subjects, before and after regular consumption of fruit kefir. | Other | BRAS-F |
| Consumption of micro-filtered fruit kefirConsumption of micro-filtered fruit kefir and measurement of the concentrations of metabolites such as BCAAs (valine, leucine, and isoleucine) in the biofluids (urine and saliva) of subjects, before and after regular consumption of fruit kefir. | Other | BRAS-P |
Primary outcome
Evaluate the effects of fruit kefir
Time frame: 3 years
Evaluate the effects of fruit kefir on the release of amino acids such as BCAAs and more generally of metabolites in human biofluids (urine and saliva). The measurement of the concentrations of metabolites such as BCAAs (valine, leucine, and isoleucine) carried out in the biofluids (urine and saliva) of subjects, before and after regular consumption of fruit kefir using IDIR enzymatic dosage kit for BCAAs in a urine sample (SkillCell, France) according to the supplier's instructions. The concentrations are expressed in µM.
6 secondary outcomes
Evaluate the effects of kefir on the well-being of participants
Time frame: 3 years
Compare the signatures of these molecular biomarkers in the saliva of subjects who consume different types of kefir preparations and subjects who consume a non-alcoholic carbonated placebo beverage
Time frame: 3 years
Compare the rate of BCAAs in the urine and saliva
Time frame: 3 years
Establish a correlation between the rate of BCAAs and the molecular signature established
Time frame: 3 years
Establish a correlation between the metabolic changes measured with the rate of BCAAs
Time frame: 3 years
Establish a correlation between the molecular signature established from the dosage
Time frame: 3 years
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 Apr 2026.
- Results publicationRenaud Debailly, Christophe Lavelle et Émilien Schultz, " Conserver un aliment vivant ", Techniques & Culture, 69 | 2018, URL : http://journals.openedition.org/tc/8971
- Results publication: PubMed 24532061Laureys D, De Vuyst L. Microbial species diversity, community dynamics, and metabolite kinetics of water kefir fermentation. Appl Environ Microbiol. 2014 Apr;80(8):2564-72. doi: 10.1128/AEM.03978-13. Epub 2014 Feb 14.
- Results publication: PubMed 41744700Molina L, Santos Schneider F, Kahli M, Ouedraogo A, Alali M, Almosnino A, Baptiste J, Boulestreau J, Davy M, Houot-Cernettig J, Mountou T, Quenot M, Simphor E, Petit V, Molina F. Capturing Emotions Induced by Fragrances in Saliva: Objective Emotional Assessment Based on Molecular Biomarker Profiles. Biosensors (Basel). 2026 Jan 28;16(2):81. doi: 10.3390/bios16020081.
- Results publication: PubMed 34822204Pendon MD, Bengoa AA, Iraporda C, Medrano M, Garrote GL, Abraham AG. Water kefir: Factors affecting grain growth and health-promoting properties of the fermented beverage. J Appl Microbiol. 2022 Jul;133(1):162-180. doi: 10.1111/jam.15385. Epub 2021 Dec 20.
- Results publication: PubMed 16854180Lopitz-Otsoa F, Rementeria A, Elguezabal N, Garaizar J. Kefir: a symbiotic yeasts-bacteria community with alleged healthy capabilities. Rev Iberoam Micol. 2006 Jun;23(2):67-74. doi: 10.1016/s1130-1406(06)70016-x.
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Healthy Adult Participants
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.
Laurence MOLINA, PhD principal investigator
Sys2Diag
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Emotion and Well-being, run by Sys2Diag at 1 site in France.
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 10 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 Apr 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 France. 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?
Evaluate the effects of fruit kefir (time frame: 3 years). 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 NCT07522372, which also lists 5 linked publications.
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 Apr 2026.