The Effect of Kombucha on Blood Sugar Levels in Humans

Study Overview
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Brief Summary
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As a phase 0 clinical trial, we will learn how kombucha influences glucose metabolism in humans.

Detailed Description
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Consumption of kombucha, a fermented tea beverage, has been promoted for a wide range of health benefits. However, a systematic literature review (Kapp & Sumner, 2019) revealed a lack of evidence for human health benefit. Despite the lack of evidence, U.S. retail sales of kombucha and other fermented beverages have increased 37.4% in 2017, and kombucha is the fastest growing product in the functional beverage market. As a phase 0 clinical trial, we will learn how kombucha influences glucose metabolism in humans. We plan for 20 subjects to take part in this study. This is a randomized-controlled counter-balanced study design. Subjects will be asked to complete 4 in-person visits over 2 months time (twice per month). At the first visit, subjects will be randomized into one of four groups. At each subsequent visit, subjects will be randomized into one of the remaining groups until they have completed each arm. Arms (at least 5 subjects in each arm, minimum total=20 subjects) Intervention group 1: commercial kombucha: drink 8oz kombucha Intervention group 2: brewed kombucha: drink 8oz kombucha Control group: drink 8oz tea (the same type as used to brew the kombucha) Control group 2: drink 8oz tap water

Official Title
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A Clinical Trial to Measure the Biochemical Response of Kombucha Tea in Humans

Conditions
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Blood Sugar; High, Glucose, Glucose Metabolism Disorders (Including Diabetes Mellitus)

Intervention / Treatment
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* Dietary Supplement: Commercial kombucha tea
* Dietary Supplement: Brewed kombucha tea
* Other: Control: Tea
* Other: Control: Water


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men or women ages 30-65 years old English-speaking Have transportation to campus Overweight (BMI >= 25 kg/m2) or obese (BMI >=30 kg/m2) Exclusion Criteria: Currently use any type of nicotine product A diagnosis of any of the following: Diabetes (type 1 or 2) Cancer COPD Chronic alcoholism Peripheral vascular disease Autoimmune disease Chronic kidney disease Pregnant or breastfeeding Prescribed medication for insulin, glucose-lowering drugs, or steroids, such as prednisone Have routinely taken prebiotic or probiotic supplements in the past 3 months Have routinely consumed any of the following more than one time per week in the past month: kombucha, kefir, yogurt, kimchi, cottage cheese, raw apple cider vinegar (with the mother), sauerkraut, kvass.

Ages Eligible for Study
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Minimum Age: 30 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intervention group 1: commercial kombucha<br>8oz | Dietary Supplement: Commercial kombucha tea<br>* Commercially-available kombucha tea.<br>|
| Experimental: Intervention group 2: brewed kombucha<br>8oz | Dietary Supplement: Brewed kombucha tea<br>* Kombucha tea brewed<br>|
| Active Comparator: Control group 1: tea<br>8oz | Other: Control: Tea<br>* Tea brewed in our lab.<br>|
| Placebo Comparator: Control group 2: water<br>8oz | Other: Control: Water<br>* Tap water<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fasting blood glucose level | Blood drawn following a 10-12 hour fast. | Baseline | 
| Fasting insulin level. | Blood drawn following a 10-12 hour fast. | Baseline | 
| Blood glucose level | Oral glucose tolerance test | 3 hour | 
| Insulin level | Oral glucose tolerance test | 3 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood pressure |  | Baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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tea, kombucha, kombucha tea, fermented food