Kombucha tea lowered blood glucose levels in T2 Diabetics, Finds a Study.

The popular fermented tea Kombucha has remarkably lowered blood glucose levels in T2 Diabetics who consumed the tea for four weeks when compared to those who consumed a similar-tasting placebo beverage as per the clinical trial reports from Georgetown University's School of Health, the University of Nebraska-Lincoln and MedStar Health. This finding, from a 12-person feasibility trial, points to the potential for dietary intervention for lowering blood sugar levels in diabetics and also establishes the basis for a larger trial to confirm and expand upon these results.

The trial results were reported in Frontiers in Nutrition on August 1, 2023.

Kombucha, a tea fermented with bacteria and yeasts, was consumed in China since 200 B.C., although it did not become popular in the United States until the 1990s. Anecdotal claims of enhanced immunity and energy, and reductions in food cravings and inflammation, have boosted its appeal, although evidence of these benefits has been lacking. As animal studies in the past have shown anti-hyperglycemic effects, Chagai Mendelson et al conducted a pilot study to evaluate kombucha for its anti-hyperglycemic activities in adults with diabetes mellitus type II. 

A prospective randomized double-blinded crossover study was carried out at a single-center urban hospital system. For four weeks, all the participants (n = 12) consumed either a kombucha product or a placebo control (each 240 mL) followed by an alternate product after an 8-week washout period. Fasting blood glucose levels were self-determined at baseline and 1 and 4 weeks during each treatment period. Secondary health outcomes like overall health, insulin requirement, gut health, skin health, mental health, and vulvovaginal health were measured by questionnaires at similar time points. The kombucha microbiota was assessed by selective culturing and 16S rRNA gene (bacteria) and ITS (fungi) sequencing. The fermentation end products were assessed by HPLC. Paired, two-tailed student’s t-tests were used to assess the statistical significance of changes in fasting blood glucose. 

Key Findings: 

• Kombucha lowered average fasting blood glucose levels at 4 weeks compared to baseline (164 vs. 116 mg/dL), whereas the placebo did not (162 vs. 141 mg/dL).
• The kombucha microbiota, as assessed by cultural enumeration, was mainly comprised of lactic acid bacteria, acetic acid bacteria, and yeast, with each group present at about 106 colony-forming units (CFU)/mL.
• Likewise, 16S rRNA gene sequencing confirmed that lactic acid and acetic acid bacteria were the most abundant bacteria, and ITS sequencing showed Dekkera was the most abundant yeast.
• The primary fermentation end products were lactic and acetic acids, both less than 1%. Ethanol was present at 1.5%.

Thus, Kombucha consumption has led to a decrease in blood glucose levels in Diabetics. This study gives a thrust to conduct further studies on a large scale to validate the biological outcomes and health benefits of in vitro studies. 

Further reading: Kombucha tea as an anti-hyperglycemic agent in humans with diabetes – a randomized controlled pilot investigation. https://doi.org/10.3389/fnut.2023.1190248