If you have diabetes and have hopped on the kombucha bandwagon (or you want to), you may be wondering whether kombucha's sugar content is safe for you to consume. While human studies are limited to date, here's where the science stands on if kombucha is good for people with diabetes.
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Behind Those Bubbles
Kombucha is a fizzy tea fermented with bacteria and yeast and sweetened with sugar, says Colorado State University. In recent years, kombucha has been touted as an elixir to potentially prevent or cure everything from your blood pressure to cancer. But there's no evidence to support these bold health claims, beyond limited evidence on kombucha's probiotic benefits (like healthy immune system promotion and constipation prevention), the Mayo Clinic says.
In fact, stomach irritation, infections and allergic reactions have all been reported from drinking the bubbly beverage. The Mayo Clinic advises that given the harm that has been reported from drinking kombucha to date, it might be best to just stay away from the brew until kombucha's safety can be confirmed with more studies.
Breaking Down the Brew
"Kombucha contains probiotics — live good bacteria called microorganisms — and antioxidants which [some studies] say can help with gut health and chronic health problems," says Audrey Koltun, RDN, CDCES, a registered dietitian and nutritionist at Cohen Children's Medical Center in Plainview, New York.
"Tea and probiotics separately are good for people with diabetes and everyone else, but kombucha tea is made with sugar," she says. "A person with diabetes needs to be aware of how much sugar is in the brand being consumed, as it can spike blood sugars — which is undesirable."
On the flip side, Koltun notes, a May 2012 animal study published in BMC Complementary and Alternative Medicine involving rats with diabetes showed the beverage's blood glucose lowering effects compared to black tea, suggesting it could possibly play a role in diabetes.
But more research is needed in humans. Closer inspection is already underway.
In a look at how kombucha can affect people with diabetes, ClinicalTrials.gov outlines a small Georgetown University-led trial, completed in July 2020, that evaluated the effect of kombucha on blood sugar levels in people with type 2 diabetes. Across a total of 10 weeks, 12 participants were first given either ginger kombucha or placebo ginger water, and then the reciprocal beverage. The study's findings are not yet published, so the verdict is still out.
Brewing Kombucha: The Potential Pitfalls
Aside from its effect on your blood sugar, though, kombucha poses other health concerns. "If you make homemade kombucha, you need to be careful to prepare it correctly so it does not produce harmful bacteria (versus healthy bacteria) and mold," Koltun says.
And, notes Michigan State University (MSU), foodborne pathogens, although rare, can be introduced at any point during food prep, so solid hygiene and sterilization practices are crucial if you make your own.
Kombucha also should be manufactured and stored in glass containers, adds MSU, because other materials can become damaged or leach due to the fermented beverage's low pH. And containers used for making or storing it should be food-grade.
For this reason, Koltun says, if you're buying your kombucha, it's a good idea to avoid (or be cautious about) farmers market selections unless you know how it's made and in what container, as clay containers or those that are high in lead content (like faulty ceramic pots, notes the Mayo Clinic) can leach lead.
Kombucha itself can pose additional risks, says MSU: namely lactic acidosis, or an accumulation of acid in the blood. If you have a compromised immune system, are pregnant or drink heavily, you may be at higher risk due to its live bacteria content. Koltun says pregnant people and children should avoid kombucha altogether.
Koltun cites these additional risks as well:
- The effect of acid on enamel, ulcers and other GI conditions.
- Bloating from carbonation.
- Calories from added sugars.
She also notes that if you have diabetes and take insulin, you need to adjust your take insulin to account for the added sugar in kombucha.
Otherwise, MSU says up to a half cup of kombucha per day is OK, which is important to note because the drink is often sold in higher portion sizes.
Read more: How Much Kombucha Should I Drink?
- Mayo Clinic: “What Is Kombucha Tea? Does It Have Any Health Benefits?”
- Audrey Koltun, RDN, CDCES, CDN, registered dietitian, nutritionist, certified diabetes care and education specialist, Cohen Children’s Medical Center, Plainview, New York
- BMC Complementary and Alternative Medicine: “Hypoglycemic and Antilipidemic Properties of Kombucha Tea in Alloxan-Induced Diabetic Rats”
- National Institutes of Health: ClinicalTrials.gov: “Evaluating the Effects of Kombucha as a Hyperglycemic Therapeutic Agent Within Diabetic Human Subjects”
- Michigan State University: “Food Safety Aspects of Kombucha”
- Colorado State University, Food Source Information: "Kombucha"
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