Type 2 Diabetes: Kombucha Tea May Help Reduce Blood Sugar Levels

Drinking kombucha every day may help lower blood sugar levels in people with type 2 diabetes. That’s according to a new study published in the journal Frontiers in Nutrition.

Researchers at Georgetown University’s School of Health the University of Nebraska-Lincoln and MedStar Health report that four weeks of drinking fermented tea (kombucha) is associated with lower (fasting) blood sugar levels in people with type 2 diabetes.

They say in a press release these findings suggest larger trials are warranted to confirm the potential benefits of drinking kombucha to reduce blood sugar levels in people with type 2 diabetes.

“This groundbreaking study unveils the initial evidence of kombucha’s potential to lower blood sugar levels in individuals with type 2 diabetes, however, further research is necessary to validate and build upon these results,” says Kelsey Costa, MS, RDN, a dietician representing the National Coalition on Healthcare (NCHC).

“I think the study’s findings show a marked improvement in the fasting blood sugar levels of those with type 2 diabetes,” says Amy Kimberlain, RDN, CDCES, a dietitian, certified diabetes care and education specialist, and Academy Media spokesperson.

Researchers looked at the effects that drinking a cup of kombucha daily for four weeks had on blood sugar. The data demonstrated that the kombucha lowered average fasting blood glucose levels from 164 to 116 milligrams per deciliter while the difference after four weeks with the placebo was not statistically significant.

The American Diabetes Association recommends blood sugar levels before meals be between 80 to 130 milligrams per deciliter.

The study had a total of 12 participants and was a crossover study, so each group received both the placebo and the kombucha for four weeks all while monitoring their levels. The study authors say there was a two-month pause period in between each trial session to ‘wash out’ any biological effects of the beverages.

Costa tells Healthline that although this pilot study was small in scale, the findings hold promise and align with the scientific understanding regarding the functional properties and potential of kombucha’s components in lowering blood sugar levels.

The researchers found kombucha to consist primarily of three key components:

“Certain types of lactic acid bacteria have functional properties that help reduce fasting blood glucose levels by preventing the absorption of post-meal blood glucose from the intestines,” says Costa.

“Acetic acid, the main component in vinegar, has been shown to delay gastric emptying and decrease fasting glucose levels in humans with type 2 diabetes. This delayed absorption of carbohydrates allows for a more gradual rise in blood sugar after meals,” she says.

“Dekkera yeast, while studied less extensively, is likely to contribute to the beneficial effects of kombucha on glucose metabolism via fermentation and by-products,” she says.

Both experts note kombucha is typically an unpasteurized product and the bacteria and yeast in kombucha make it unsuitable for people during pregnancy and people with weakened immune systems, i.e., people with cancer, or kidney disease.

“Kombucha offers a multitude of health benefits that make it a wholesome addition to one’s diet, particularly for those seeking to enhance blood sugar control,” says Costa.

“One of the purported benefits of kombucha is that kombucha contains probiotics,” says Kimberlain. “While there isn’t yet the evidence to show the probiotic benefits of kombucha, it does contain several species of lactic acid bacteria, which could in turn have a probiotic function.”

She points to a research review suggesting probiotics may play a role in:

Besides probiotics, Kimberlain says kombucha also contains polyphenols or antioxidants that can help to protect against various diseases.

“Kombucha is also a rich source of antioxidants called flavonoids, especially those made with green and red tea types,” adds Costa.

“Incorporating kombucha into your regular diet may also help support your body’s antioxidative response, which is especially important during times of increased mental and physical stress,” Costa tells Healthline.

“It’s important to note that not all kombuchas are created in the same manner,” says Kimberlain.

The kombucha used in the study was produced and donated by Craft Kombucha, a commercial manufacturer in the Washington, DC, area. It has been rebranded as Brindle Boxer Kombucha. No author has any financial ties with Craft Kombucha.

“Different studies of different brands of kombucha by different manufacturers reveal slightly different microbial mixtures and abundances,” says Robert Hutkins, PhD, University of Nebraska-Lincoln and the study’s senior author. “However, the major bacteria and yeasts are highly reproducible and likely to be functionally similar between brands and batches, which was reassuring for our trial.”

Kimberlain says since there are many different brands or makes of kombucha, it’d be important to study more specifically if these benefits were seen from green tea kombucha versus black tea kombucha, along with the amount of added sugar (as that is used to ferment the tea, but yet could play a role in blood sugar levels if there is excessive sugar and/or juice used to create the kombucha).

Costa adds that choosing kombucha in dark bottles is best because it blocks light, and light can damage the beneficial compounds in kombucha.

And while making kombucha at home is technically possible, Costa says proper sanitation and ingredient use are crucial to prevent contamination.

“When choosing kombucha, read the label and opt for lower-sugar and lower-calorie options,” says Costa.

Kimberlain says paying attention to added sugar is important because some brands have more added sugar used than others, and added sugar has been shown to contribute to obesity, fatty liver, heart disease, and increase blood sugar levels.

According to the American Heart Association, the maximum amount of added sugar to consume a day is 36 grams (9 teaspoons) for men and 25 grams (6 teaspoons) for women.

Kimberlain tells Healthline lower-sugar brands of kombucha have about 4 grams of sugar = 1 teaspoon per serving.

“It’s always important to talk to your health care provider before starting anything new, even drinking kombucha,” Kimberlain says to Healthline.

Costa recommends that if you have type 2 diabetes, consult with your health care provider to determine an appropriate intake of kombucha. She also says more research is needed before it can be recommended as a treatment option.

“Kombucha should not be used in place of traditional diabetes treatments such as lifestyle modifications, medications, or insulin therapy,” Costa tells Healthline.

“No one food or beverage can cure diabetes, but incorporating functional foods such as kombucha into an overall balanced diet can go a long way in aiding diabetes management,” she says.

Kombucha contains about the same amount of caffeine as in a cup of traditional tea and could add up depending on how much you drink.

Kombucha is not recommended for women who are pregnant and/or breastfeeding, or for kids, due to the caffeine and low alcohol content.

If you decide to start drinking kombucha (after checking with your health care provider), it’s best to purchase kombucha rather than try to make it at home.

Start off with a small amount of kombucha initially.

Always monitor your blood sugar levels to see if there is any impact on your overall blood sugar management. (Every person is impacted differently.)