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Obesity and OverweightKOMBIOMENCT06759324

Kombucha in Overweight and Obese: Live Vs. Pasteurized Effects on Microbiota, Metabolism, and Liver Function

A study testing Live kombucha (non filtered/ non pasteurized) and Pasteurized kombucha (non filtered) in people with Obesity and Overweight, run by Associação Centro de Apoio Tecnológico Agro Alimentar at 2 sites in Portugal.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

Kombucha, a fermented beverage made from Camellia sinensis tea (black, oolong, or green) with sugar and a symbiotic culture of bacteria and yeast (SCOBY), has gained global attention for its potential health benefits. Read more about this study

Who is it for?
Ages 18 to 60 years
Conditions the study is for
Obesity and Overweight
What is being tested?
Live kombucha (non filtered/ non pasteurized) and Pasteurized kombucha (non filtered)
Could I receive a placebo?
No, everyone receives an active treatment
How many people
33 participants
Where
2 sitesPortugal
Study dates
11 Oct 2024to 28 Feb 2025
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 60 years
  • All sexes
  • No healthy volunteers
  • Adult

Who may be able to join

  • Individuals with a Body Mass Index (BMI) between 25 kg/m² and 34.9 kg/m², of both biological sexes, aged between 18 and 60 years, available to comply with the study protocol (described in this document) and sign informed consent.

Who cannot join

  • Volunteers will be excluded from the study if they present one or more of the following conditions:
  • Subjects with sensitivity to kombucha;
  • Consumption of kombucha, kefir, kimchi, cheese, raw vinegar, sauerkraut, kvass, and other fermented products during the study and in the 3 weeks before the study.
  • Use of antibiotics in the 6 months prior to the start of the study;
  • Use of pro/prebiotics or fibers as dietary supplements or any food/molecule that modifies intestinal transit time 6 weeks before recruitment; use of laxatives 6 weeks before recruitment;
  • Specific dietary regimen (e.g., vegan); specific dietary treatment (e.g., high protein);
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  • Excessive consumption of substances and alcohol; smokers;
  • Diagnosis of gastrointestinal disorders, hormonal or thyroid diseases, autoimmune diseases, and/or chronic use of corticosteroids; psychiatric disease; Type 1 or 2 diabetes;
  • Use of proton pump inhibitors; antidiabetic drugs or insulin and statins;
  • Subjects with insulin sensitivity;
  • Pregnant or lactating women;
  • Subjects with tooth sensitivity
  • Participation in another clinical trial in the last 3 months.

Trial locations and contacts

2 sites in 1 country. Contact the study team or a site near you to ask about taking part.

Inês Brandão, PhD contact

+351926777221

inesbrandao@cataa.pt

Filomena Pereira, Nutritionist contact

filomenapereira@cataa.pt

Portugal2 sites, 2 recruiting
  • Centro de Apoio Tecnológico Agro Alimentar (CATAA)

    Castelo Branco, Castelo Branco District, 6000-459

    Inês Brandão, PhD, +351926777221, inesbrandao@cataa.pt

    Filomena Pereira, M.Sc. (Nutritionist), +351912069989, nutricao@cataa.pt

    Recruiting
  • Centro de Apoio Tecnológico Agro Alimentar (CATAA) (facilities temporarily provided by the Affidea clinical analysis center)

    Covilha, 6200-077

    Filomena Pereira, MSc (Nutritionist), +351912069989, nutricao@cataa.pt

    Recruiting

Other trials in Portugal

About this study

Official title: Randomized Controlled Pilot Clinical Study Including Kombucha in the Diet of Individuals with Overweight and Class 1 Obesity: Comparative Assessment Between Live and Pasteurized Kombucha and Its Effects on Gut Microbiota, Metabolic Parameters, and Liver Function [FUSILLI Project -H2020]

Kombucha, a fermented beverage made from Camellia sinensis tea (black, oolong, or green) with sugar and a symbiotic culture of bacteria and yeast (SCOBY), has gained global attention for its potential health benefits. Factors like the type and amount of sugar substrate, fermentation time, and temperature significantly influence its organic compounds, total phenolics, vitamin content, and alcohol levels.

In a previous study, kombucha's impact on glucose tolerance, insulin sensitivity, body composition, and liver function was tested in male prediabetic mice with diet-induced obesity. Daily supplementation (200 µL per mouse) improved glucose tolerance after nine days (equivalent to one year in humans) and reduced liver steatosis, despite no changes in body composition.

Although kombucha has been associated with antioxidant, antimicrobial, probiotic, antidiabetic, and anticancer activities, strong scientific evidence in humans remains limited. Further clinical studies are needed to substantiate kombucha's health benefits in humans.

Read the detailed description

The objectives of this clinical study aim to explore the effects of kombucha on the health of individuals with overweight and class 1 obesity, while also determining whether the kombucha microbiota plays a role in the observed effects. Specifically, by investigating metabolic parameters such as glucose and insulin levels and lipid profile, as well as the composition and diversity of the gut microbiota and liver function, the study will contribute to a deeper understanding of the potential benefits and mechanisms of action of kombucha consumption in humans. The study aims to recruit at least 30 individuals with overweight and class 1 obesity, aged between 18 and 60 years, randomly distributed into 3 arms (each arm should have about 10 participants). The first arm receives a daily amount of 33 cl of kombucha (live drink) for 4 weeks, the second arm receives a daily amount of 33 cl of kombucha (pasteurized drink) for 4 weeks. The control group receives 33 cl of sparkling water for 4 weeks.

Being tested
Live kombucha (non filtered/ non pasteurized), Pasteurized kombucha (non filtered), Control (sparkling water)
Keywords
kombucha, gut microbiota, obesity, liver function, fermented beverages, Randomized Controlled Trial, overweight, fermented tea, SCOBY, live vs pasteurized kombucha, Small Intestinal Bacterial Overgrowth (SIBO), Bristol Stool Form Scale, Likert Scale Analysis, Nutritional Interventions, Inflammatory Biomarkers, metabolic parameters
Medical subject headings
Obesity, Overweight

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Live kombucha (non filtered/ non pasteurized)Dietary supplement

    Participants receive a daily amount of 33 cl of live kombucha (non-pasteurized/ non-filtered) for 4 weeks (28 days).

  • Pasteurized kombucha (non filtered)Dietary supplement

    Participants receive a daily amount of 33 cl of kombucha (pasteurized drink) for 4 weeks (28 days).

  • Control (sparkling water)Other

    Participants receive a daily amount of 33 cl of sparkling water for 4 weeks.

Study groups in NCT06759324
Study groupRoleWhat they receive
Intervention: Kombucha (live drink)ExperimentalThe first arm receives a daily amount of 33 cl of kombucha (live drink) for 4 weeks (dietary supplement).
Receives: Dietary Supplement: Live kombucha (non filtered/ non pasteurized)
Intervention: Pasteurized kombuchaExperimentalThe second arm receives a daily amount of 33 cl of kombucha (pasteurized drink) for 4 weeks (dietary supplement).
Receives: Dietary Supplement: Pasteurized kombucha (non filtered)
Sparkling waterActive comparatorThe third arm receives 33 cl of sparkling water for 4 weeks (control).
Receives: Other: Control (sparkling water)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in Gut microbiota composition and diversity (fecal samples)

    Analyze the changes in the relative abundance of the microbial species present, including taxonomic identification and diversity analysis, from baseline to the end of intervention, by next-generation sequencing (NGS).

    Measured: 4 weeks

  2. Change in fasting glucose levels

    Fasting glucose (mg/dl), from baseline to the end of intervention. Reduction is a better outcome.

    Measured: 4 weeks

  3. Change in fasting insulin levels

    Fasting insulin (μUI/mL), from baseline to the end of intervention. Reduction is a better outcome.

    Measured: 4 weeks

  4. Changes in Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) values

    HOMA-IR values, from baseline to the end of intervention. Calculated from fasting glucose (mmol/L) X fasting insulin (mU/L) / 22.5). Less than 1.0 means insulin-sensitive, which is optimal. Above 1.9 indicates early insulin resistance. Above 2.9 indicates significant insulin resistance. Reduction is a better outcome.

    Measured: 4 weeks

  5. Changes in Lipid profile

    Lipid profile (total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides), in mg/dL, from baseline to the end of intervention.

    Measured: 4 weeks

Secondary outcomes (9)
  1. Stool consistency rating by Bristol Stool Scale

    The Bristol Stool Chart is a medical tool used to classify human feces into seven distinct categories. This scale is widely regarded as the gold standard for evaluating stool consistency and intestinal transit time in adults. It ranges from type 1 (separate hard lumps), which indicates the slowest transit time and constipation, to type 7 (watery with no solid pieces), representing the fastest transit time. Daily monitoring questionnaire (to evaluate 1 to 7), from baseline to the end of intervention.

    Measured: 4 weeks

  2. Variation in SIBO diagnosis (positive/negative) measured by methane and hydrogen levels in breath test

    Hyrogen and methane lactulose breath test, in ppm, from baseline to end of intervention. Interpretation criteria: SIBO test is positive if there is an early increase (in the first 90 minutes) equal to or greater than 20 ppm of H2 and/or equal to or greater than 10 ppm of CH4, when compared with the lowest value obtained.

    Measured: 4 weeks

  3. Change in liver enzyme levels

    Analyze liver enzymes (units: in UI/L) such as alkaline phosphatase, alanine transaminase, aspartate transaminase, gamma-glutamyl transferase, from baseline to end of intervention, to determine potential hepatic effects of Kombucha consumption.

    Measured: 4 weeks

  4. Change in levels of oxidative stress biomarker (ratio 8-iso-PGF2α to prostaglandin F2α (PGF2α))

    Measure of oxidative stress biomarker (pg/mL ), from baseline to the end of intervention. Normal human plasma reference values: 40-100 pg/mL.

    Measured: 4 weeks

  5. Change in gastrointestinal symptoms using a Likert scale

    Evaluate gastrointestinal symptoms (e.g., bloating, gas) using a 10-point Likert scale, from baseline to the end of intervention. The daily questionnaire goes from zero (0) which means "no pain" to ten (10) which means "worst pain imaginable".

    Measured: 4 weeks

  6. Change in high-sensitive C-reactive protein levels

    Levels of h-sensitivity C-reactive protein (hsCRP), a marker of inflammation, in mg/dL, from baseline to the end of intervention. hsCRP levels of less than 0.100, 0.100 to 0.300, and greater than 0.301 mg/dL are associated with lower, moderate, and higher cardiovascular risks, respectively.

    Measured: 4 weeks

  7. Change in Total oxidant capacity

    Oxidative stress biomarker, pg/mL, measured from baseline to the end of intervention. Normal values range from 40-100.

    Measured: 4 weeks

  8. Changes in serum albumin and bilirubin levels

    Evaluate hepatobiliary function, albumin (g/dL), Bilirubin (mg/dL)

    Measured: 4 weeks

  9. Changes in short chain fatty acids in stool

    SCFAs in stool, units µM

    Measured: 4 weeks

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted6 Jan 2025
  2. Study start11 Oct 2024
  3. Primary completion28 Feb 2025 (estimated)
  4. Study completion28 Feb 2025 (estimated)

Resources

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
The study aims to recruit at least 30 individuals with overweight and class 1 obesity, aged between 18 and 60 years, randomly distributed into 3 arms (each arm should have about 10 participants). The first arm receives a daily amount of 33 cl of kombucha (live drink) for 4 weeks, the second arm receives a daily amount of 33 cl of kombucha (pasteurized drink) for 4 weeks. The control group receives 33 cl of water for 4 weeks. Kombucha samples are prepared for the study by Erfrischerling GmbH \& Co. KG (Germany).
Masking
Triple blind
Who is masked
Participant, Investigator, Outcomes assessor
Enrolment
33 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06759324
Sponsor's protocol ID
FUSILLI: PARECER (02/2024)
Other IDs
Grant agreement No. 101000717
Acronym
KOMBIOME
Status last verified
Dec 2024
First submitted
9 Dec 2024
Last updated
6 Jan 2025
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • Moreira GV, Araujo LCC, Murata GM, Matos SL, Carvalho CRO. Kombucha tea improves glucose tolerance and reduces hepatic steatosis in obese mice. Biomed Pharmacother. 2022 Nov;155:113660. doi: 10.1016/j.biopha.2022.113660. Epub 2022 Sep 12.

    PubMed 36095960

Questions about this trial

What is this clinical trial studying?

A study testing Live kombucha (non filtered/ non pasteurized) and Pasteurized kombucha (non filtered) in people with Obesity and Overweight, run by Associação Centro de Apoio Tecnológico Agro Alimentar at 2 sites in Portugal.

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 1 inclusion and 13 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: looking for participants now, as of the sponsor's last update on 6 Jan 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites in Portugal. 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?

Contact Inês Brandão, PhD (+351926777221, inesbrandao@cataa.pt), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in Gut microbiota composition and diversity (fecal samples) (time frame: 4 weeks). The study lists 5 primary outcomes in all. 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 NCT06759324, 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 6 Jan 2025; AzTrials last refreshed its copy on 1 Nov 2026.

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