Clinical trial

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

Recruiting now · Not applicable · 1 countries · Registry ID NCT06759324

Recruiting nowNot applicableInterventional

What this study is about

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.

A promising-looking record is not the same as confirmed eligibility. The study team must review the full criteria and current recruitment status.

Basic eligibility

Age18 Years to 60 Years
SexAll
Healthy volunteersNot accepted
ConditionObesity and Overweight

Full registry 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.

Treatments and study arms

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.

Primary outcomes

Change in Gut microbiota composition and diversity (fecal samples)4 weeks

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).

Change in fasting glucose levels4 weeks

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

Change in fasting insulin levels4 weeks

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

Changes in Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) values4 weeks

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.

Changes in Lipid profile4 weeks

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

Study locations

2 locations were listed when this page was built. The first 40 are shown.

Centro de Apoio Tecnológico Agro Alimentar (CATAA)🇵🇹 Castelo Branco, Castelo Branco District, Portugal
Inês Brandão, PhDContact
Filomena Pereira, M.Sc. (Nutritionist)Contact
Inês Brandão, PhDContact
Centro de Apoio Tecnológico Agro Alimentar (CATAA) (facilities temporarily provided by the Affidea clinical analysis center)🇵🇹 Covilha, Portugal
Filomena Pereira, MSc (Nutritionist)Contact