Kombucha is an infusion that is made from tea fermented with yeast and bacteria, which was already consumed in China in the year 200 BC. C., but that did not become popular in the United States until the 1990s. Since then, its popularity has increased because certain beneficial properties have been attributed to it, from helping to reduce blood pressure or cholesterol, to providing energy, to balancing the intestinal flora or to reducing inflammation, although they are not supported by scientific studies.
New research has now found an incentive to consume this drink, however, as it reveals that people with type 2 diabetes who drank kombucha for four weeks had lower fasting blood glucose levels compared to when they drank a drink taste-like placebo.
This clinical trial has been conducted by researchers from the Georgetown University School of Health, the University of Nebraska-Lincoln, and MedStar Health and its results have just been published in Frontiers in Nutrition. This is a small pilot trial involving only 12 people, but it suggests the potential for a dietary intervention that could help lower blood sugar levels in people with diabetes and also sets the stage for a larger trial. large to confirm and extend these results.
“We were able to provide preliminary evidence that a common beverage {kombucha} might have an effect on diabetes”
“Some laboratory and rodent studies on kombucha have shown promise, and a small study in people without diabetes showed that kombucha lowered blood sugar, but to the best of our knowledge, this is the first clinical trial to examine the effects of kombucha in people with diabetes,” said study author Dr. Dan Merenstein, professor of human sciences at Georgetown School of Health and professor of family medicine at Georgetown University School of Medicine. “A lot more research needs to be done, but this is very promising.”
Components of kombucha beneficial to health
The study featured a “crossover design” whereby one group of participants drank about 236 milliliters of kombucha daily for four weeks and a second group drank a placebo drink. Following a two-month period to “wash out” the biological effects of the drinks, the kombucha and placebo were switched between the groups with another four weeks of drinking the drinks. None of the participants was informed about which drink they were receiving at any given time.
Drinking kombucha appeared to reduce average fasting blood glucose levels after four weeks from 164 to 116 milligrams per deciliter, while the difference after taking placebo for four weeks was not statistically significant. The American Diabetes Association guidelines recommend that blood sugar levels before meals be between 70 and 130 milligrams per deciliter.
The researchers also looked at the composition of the fermenting microorganisms in the kombucha to determine which ingredients might be the most active. They found that the drink was made up primarily of lactic acid bacteria, acetic acid bacteria, and a form of yeast called Dekkera, with each microbe present in roughly equal measure; the finding was confirmed with RNA gene sequencing.
The composition of kombucha is complex and further research is needed to analyze and identify the specific components, or combinations of components, that provide the apparent health benefit. Potential agents involved in the beneficial “mechanism of action” include microbes, but also metabolites found in kombucha, including ethanol, lactic and acetic acids, tea constituents, and flavoring ingredients.
The kombucha used in this study was produced by Craft Kombucha, a commercial manufacturer in the Washington, DC area. It has been renamed Brindle Boxer Kombucha. “Different studies of different brands of kombucha by different manufacturers reveal slightly different mixes and microbial abundances,” said Robert Hutkins of the University of Nebraska-Lincoln and lead author of the study. “However, the main bacteria and yeast are highly reproducible and are likely to be functionally similar between brands and batches, which was reassuring for our test.”
“We were able to provide preliminary evidence that a common drink could have an effect on diabetes. We hope that a much larger trial can be conducted, using the lessons we learned in this trial, to give a more definitive answer to the efficacy of kombucha in lowering blood glucose levels and therefore preventing or helping treating type 2 diabetes,” concludes lead author Dr. Chagai Mendelson, who was working in Merenstein’s lab in Georgetown while completing his residency at MedStar Health.
