Kombucha is a fermented tea that has benefits such as improving gut health.
Researchers were curious whether the probiotic beverage could be helpful in lowering blood sugar and conducted a study with people with type 2 diabetes.
The scientists gave two groups of people with type 2 diabetes either kombucha or a placebo drink that tasted similar for 4 weeks and then tested their blood sugar levels. After a break, they switched the groups and tested the participants after another 4 weeks.
The findings showed that kombucha for 4 weeks significantly decreased fasting blood glucose levels compared to baseline whereas placebo did not.
According to the researchers, this is the first study testing kombucha in people with type 2 diabetes.
Type 2 diabetes is a condition in which the body struggles to either make or manage insulin effectively. Millions of people in the United States have diabetes, and according to the Centers for Disease Control and Prevention (CDC)Trusted Source, this condition is the eighth leading cause of death in the country.
As type 2 diabetes rates increase, scientists are interested in finding different methods to lower blood sugar, including through diet choices.
Researchers from Georgetown University’s School of Health in Washington D.C. wanted to learn whether kombuchaTrusted Source, a tea that originates from China and is fermented with bacteria and yeasts, could improve blood sugar levels.
After comparing blood sugar averages between drinking kombucha or a placebo, they learned that just 4 weeks of drinking kombucha lowered fasting blood sugar levels before meals from 164 to 116 milligrams per deciliters (mg/dL) on average.
For comparison, the American Diabetes Association says normal fasting glucose before meals is 80–130 mg/dL.
The study is published in Frontiers in Nutrition.
Monitoring fasting glucose
The researchers recruited participants from MedStar Georgetown University Hospital’s General Internal Medicine Clinic, a facility the authors note has “a strong interest in diabetes care.”
They enlisted 12 participants for the study, all of whom had type 2 diabetes. They had to agree to drink their assigned beverage daily and be willing to test their fasting glucose at home at different periods.
Additionally, the researchers instructed the participants to follow their typical diets. They did not want dietary changes to influence potential blood sugar decreases.
After dividing the participants into two groups, the researchers provided each participant with an 8-ounce beverage they had to drink daily with dinner for a period of 4 weeks. Some people received kombucha, and others received a placebo drink that the authors say tasted similar to kombucha.
For the next portion of the study, the researchers reversed who got the kombucha. To account for any lingering effects of kombucha, the scientists had the participants wait 8 weeks until restarting the drinking regimen.
After the 8-week “washout period” was up, the participants again underwent 4 weeks of drinking their assigned beverage. People who drank kombucha in the first round of the study drank the placebo drink while the others drank kombucha.
From there, the researchers analyzed the data the participants provided on their fasting glucose., which they measured at the following intervals:
their baseline before beginning the drinking regimen
at the end of week 1
at the end of week 4
after the washout period
at the end of week 1 of the second round
at the end of week 4 of the second round.
Kombucha drinkers had lower blood sugar
The scientists took an average of the participants’ baseline data and then the data for each 4-week round of kombucha and placebo beverages to see whether kombucha improved glucose levels.
The average baseline glucose level for the participants was 164 mg/dL, and after 4 weeks of drinking kombucha, the average dropped to 116 mg/dL. This is a decrease of nearly 30% for the kombucha group.
By comparison, there was little change in the participants’ baseline blood glucose levels after drinking the placebo beverage.
“The placebo was not associated with a statistically significant change in average fasting blood glucose levels,” write the authors.
The researchers noted that the small sample size is a limitation of the study and said a larger study is needed.
“We were able to provide preliminary evidence that a common drink could have an effect on diabetes,” lead study author Dr. Chagai Mendelson said in a press release.
“We hope that a much larger trial, using the lessons we learned in this trial, could be undertaken to give a more definitive answer to the effectiveness of kombucha in reducing blood glucose levels, and hence prevent or help treat type 2 diabetes,” he added.
Dr. Mendelson is completing a residency program at MedStar Georgetown University Hospital Medical School.
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