Type 2 Diabetes Patients Experience Lower Blood Sugar Levels After Kombucha Consumption

Kombucha, a fermented tea beverage, has been linked to decreased fasting blood glucose levels in individuals with type 2 diabetes over a four-week period, compared to a placebo drink, according to research. This initial study hints at the potential of a dietary change as a means to lower blood sugar levels in diabetics, forming the foundation for a more substantial, thorough trial.

The initial, small-scale study calls for larger trials to validate the potential benefits of this fermented drink.

This clinical trial, led by researchers from Georgetown University’s School of Health, the University of Nebraska-Lincoln, and MedStar Health, saw type 2 diabetes patients who drank kombucha for four weeks experience lower fasting blood glucose levels than when they consumed a placebo beverage. The results from this preliminary 12-person trial suggest that kombucha could potentially be part of a dietary intervention strategy to help control blood sugar levels in diabetics. It also paves the way for a larger, more extensive trial to further investigate these findings.

These results were published in the Frontiers in Nutrition journal on August 1, 2023.

Kombucha Background

Kombucha is a tea fermented with bacteria and yeast that has been consumed since 200 B.C. in China, but only became popular in the U.S. during the 1990s. Its popularity is largely due to anecdotal evidence suggesting improvements in immunity and energy, decreased food cravings and inflammation, though empirical evidence supporting these benefits is sparse.

According to study author Dan Merenstein, M.D., professor of Human Sciences at Georgetown’s School of Health and professor of family medicine at Georgetown University School of Medicine, this is the first clinical trial examining kombucha’s effects in individuals with diabetes. He stresses that more research is needed, but the early signs are promising.

Study Details and Findings

Merenstein mentioned a key strength of their trial was its crossover design, which minimized the impact of diet variability among participants. In this study, one group drank roughly eight ounces of kombucha or a placebo beverage daily for four weeks. After a two-month period to ‘wash out’ the biological effects of the beverages, the kombucha and placebo were swapped between the groups, with another four weeks of beverage consumption. The participants were not informed which beverage they were receiving at the time.

The study found that kombucha reduced average fasting blood glucose levels from 164 to 116 milligrams per deciliter after four weeks. The American Diabetes Association suggests that blood sugar levels before meals should be between 70 to 130 milligrams per deciliter.

Kombucha Composition and Brand

Researchers also examined the composition of fermenting microorganisms in kombucha to determine the most active ingredients. The beverage was found to be primarily composed of lactic acid bacteria, acetic acid bacteria, and a yeast known as Dekkera; this was confirmed through RNA gene sequencing.

The kombucha used in the study was provided by Craft Kombucha, a commercial manufacturer based in Washington, DC, which has since been re-branded as Brindle Boxer Kombucha.

Robert Hutkins, Ph.D., University of Nebraska-Lincoln and the study’s senior author, noted that different brands of kombucha have slightly different microbial compositions, but the main bacteria and yeasts are consistent and likely to be functionally similar across brands and batches.

Wider Implications

Chagai Mendelson, M.D., the study’s lead author, underscored the broader context of this work. Given that diabetes is a major risk factor for heart disease, stroke, and kidney failure and is the eighth leading cause of death in the U.S., the study provided preliminary evidence that a widely available beverage could affect diabetes. The team hopes to initiate a larger trial based on the lessons learned from this study to definitively determine the effectiveness of kombucha in reducing blood glucose levels and potentially aiding in the prevention or treatment of type 2 diabetes.

The study was not externally funded, and the kombucha and placebo drinks were donated by Craft Kombucha. The authors have no financial ties with Craft Kombucha, and Craft Kombucha had no access to the study’s data. All authors have disclosed their potential conflicts of interest.

Frequently Asked Questions (FAQs) about Kombucha and diabetes

More about Kombucha and diabetes

• Effects of Kombucha on blood glucose levels
• Overview of Type 2 Diabetes
• Information about Kombucha
• American Diabetes Association blood sugar level guidelines