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| ID | Type | Description | Link |
|---|---|---|---|
| 24.00472.000223 | Other Identifier | Comité de protection des personnes (French Ethics committee) |
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| Name | Class |
|---|---|
| Centre National de la Recherche Scientifique, France | OTHER |
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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.
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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| BRAS-C | Consumption of a control beverage, non-fermented carbonated drink |
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| BRAS-F | Consumption of fruit kefir |
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| BRAS-P | Consumption of micro-filtered fruit kefir |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Consumption of a control beverage, non-fermented carbonated drink | Other | 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. |
| Measure | Description | Time Frame |
|---|---|---|
| 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. | 3 years |
| Measure | Description | Time Frame |
|---|---|---|
| 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. |
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Inclusion Criteria :
Exclusion Criteria :
Criteria for Discontinuation of Participation in the Research :
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A total of 66 subjects will be recruited on a voluntary basis :
The distribution of subjects into the 3 BRAS will be carried out by a controlled randomized method.
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| Name | Affiliation | Role |
|---|---|---|
| Laurence MOLINA, PhD | Sys2Diag | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| SYS2DIAG - UMR9005 CNRS/ALCEN, Montpellier, 34184 | Montpellier | France |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| Result | Renaud Debailly, Christophe Lavelle et Émilien Schultz, " Conserver un aliment vivant ", Techniques & Culture, 69 | 2018, URL : http://journals.openedition.org/tc/8971 | ||
| 24532061 | Result | 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. | |
| 41744700 |
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Saliva and urine
|
| Consumption of fruit kefir | Other | 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 kefir | Other | 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. |
|
| 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. | 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. | 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. | 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. | 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. | 3 years |
| Result |
| Molina 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. |
| 34822204 | Result | Pendon 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. |
| 16854180 | Result | Lopitz-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. |