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

NCT ID: NCT06759324

Last Updated: 2025-01-06

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 33 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2024-10-11
• Study Completion Date: 2025-02-28

Brief 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. 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.

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.

Conditions

Obesity and Overweight

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: OTHER
• Blinding Strategy: TRIPLE

Study Groups

Intervention: Kombucha (live drink)

The first arm receives a daily amount of 33 cl of kombucha (live drink) for 4 weeks (dietary supplement).

Group Type: EXPERIMENTAL

Live kombucha (non filtered/ non pasteurized)

Intervention Type: DIETARY_SUPPLEMENT

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

Intervention: Pasteurized kombucha

The second arm receives a daily amount of 33 cl of kombucha (pasteurized drink) for 4 weeks (dietary supplement).

Group Type: EXPERIMENTAL

Pasteurized kombucha (non filtered)

Intervention Type: DIETARY_SUPPLEMENT

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

Sparkling water

The third arm receives 33 cl of sparkling water for 4 weeks (control).

Group Type: ACTIVE_COMPARATOR

Control (sparkling water)

Intervention Type: OTHER

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

Interventions

Live kombucha (non filtered/ non pasteurized)

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

Intervention Type: DIETARY_SUPPLEMENT

Pasteurized kombucha (non filtered)

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

Intervention Type: DIETARY_SUPPLEMENT

Control (sparkling water)

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

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

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.

Exclusion Criteria

Volunteers will be excluded from the study if they present one or more of the following conditions:

1. Subjects with sensitivity to kombucha;

2. 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.

3. Use of antibiotics in the 6 months prior to the start of the study;

4. 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;

5. Specific dietary regimen (e.g., vegan); specific dietary treatment (e.g., high protein);

6. Excessive consumption of substances and alcohol; smokers;

7. Diagnosis of gastrointestinal disorders, hormonal or thyroid diseases, autoimmune diseases, and/or chronic use of corticosteroids; psychiatric disease; Type 1 or 2 diabetes;

8. Use of proton pump inhibitors; antidiabetic drugs or insulin and statins;

9. Subjects with insulin sensitivity;

10. Pregnant or lactating women;

11. Subjects with tooth sensitivity

12. Participation in another clinical trial in the last 3 months.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 60 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Associação Centro de Apoio Tecnológico Agro Alimentar

OTHER

Sponsor Role: lead

Responsible Party

Inês Brandão

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Brandão, PhD

Role: PRINCIPAL_INVESTIGATOR

CATAA

Locations

Centro de Apoio Tecnológico Agro Alimentar (CATAA)

Castelo Branco, Castelo Branco District, Portugal

Site Status: RECRUITING

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

Covilha, , Portugal

Site Status: RECRUITING

Countries

Portugal

Central Contacts

Inês Brandão, PhD

Role: CONTACT

inesbrandao@cataa.pt

+351926777221

Filomena Pereira, Nutritionist

Role: CONTACT

filomenapereira@cataa.pt

Facility Contacts

Inês Brandão, PhD

Role: primary

inesbrandao@cataa.pt

+351926777221

Filomena Pereira, M.Sc. (Nutritionist)

Role: backup

nutricao@cataa.pt

+351912069989

Inês Brandão, PhD

Role: backup

Filomena Pereira, MSc (Nutritionist)

Role: primary

nutricao@cataa.pt

+351912069989

References

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.

Reference Type: BACKGROUND

PMID: 36095960 (View on PubMed)

Other Identifiers

Grant agreement No. 101000717

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

FUSILLI: PARECER (02/2024)

Identifier Type: -

Identifier Source: org_study_id