Clinical trial NCT06759324: Kombucha in Overweight and Obese: Live Vs. Pasteurized Effects on Microbiota, Metabolism, and Liver Function
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]
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Obesity and Overweight
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
Lead sponsor: Associação Centro de Apoio Tecnológico Agro Alimentar
Sponsor class: OTHER
First posted: 2025-01-06
Enrollment: 33
Sex: ALL
Minimum age (years): 18
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention 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).
Primary purpose: OTHER

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.

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.

Primary outcomes:
measure: Change in Gut microbiota composition and diversity (fecal samples)
timeFrame: 4 weeks
measure: Change in fasting glucose levels
timeFrame: 4 weeks
measure: Change in fasting insulin levels
timeFrame: 4 weeks
measure: Changes in Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) values
timeFrame: 4 weeks
measure: Changes in Lipid profile
timeFrame: 4 weeks
Secondary outcomes:
measure: Stool consistency rating by Bristol Stool Scale
timeFrame: 4 weeks
measure: Variation in SIBO diagnosis (positive/negative) measured by methane and hydrogen levels in breath test
timeFrame: 4 weeks
measure: Change in liver enzyme levels
timeFrame: 4 weeks
measure: Change in levels of oxidative stress biomarker (ratio 8-iso-PGF2α to prostaglandin F2α (PGF2α))
timeFrame: 4 weeks
measure: Change in gastrointestinal symptoms using a Likert scale
timeFrame: 4 weeks
measure: Change in high-sensitive C-reactive protein levels
timeFrame: 4 weeks
measure: Change in Total oxidant capacity
timeFrame: 4 weeks
measure: Changes in serum albumin and bilirubin levels
timeFrame: 4 weeks
measure: Changes in short chain fatty acids in stool
timeFrame: 4 weeks
Other outcomes:
measure: Body weight change
timeFrame: 4 weeks
measure: BMI change
timeFrame: 4 weeks
measure: Waist circumference change
timeFrame: 4 weeks
measure: Body fat percentage change
timeFrame: 4 weeks
measure: Changes in kidney function biomarkers- creatinin, urea and uric acid
timeFrame: 4 weeks
Locations:
city: Castelo Branco
country: Portugal
facility: Centro de Apoio Tecnológico Agro Alimentar (CATAA)
city: Covilhã
country: Portugal
facility: Centro de Apoio Tecnológico Agro Alimentar (CATAA) (facilities temporarily provided by the Affidea clinical analysis center)
Study officials:
affiliation: CATAA
name: Brandão, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: 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.