ablokhin/Getty Images
- Kombucha is a fermented drink made from adding sugar and yeast to tea.
- Kombucha is rich in probiotics and antioxidants, which may help prevent heart disease.
- To make kombucha, you'll have to let it ferment for one to four weeks.
- Visit Insider's Health Reference library for more advice.
Thanks to the growing interest in probiotics, kombucha can be found everywhere from health food stores and supermarkets to online retailers and your local bar.
While this fizzy tea is only recently popular in places like the US, folks in China – where the drink is thought to have originated – have been drinking it for millennia, as far back as 226 BC, according to some estimates.
Whether you're interested in trying one of the many commercially available kombuchas or making it yourself at home, here's what you need to know about this trendy beverage.
What is kombucha?
Kombucha is a fermented tea made by adding sugar and yeast to black or green tea, resulting in a lightly carbonated drink with a distinctly tart flavor.
Kombucha ferments for at least a week, according to Kristin Gillespie, a registered dietitian and certified nutrition support clinician at Exercise with Style. During this time, bacteria and yeasts break down the sugar and produce acetic acid, as well as trace amounts of alcohol.
Commercial kombucha can't contain more than 0.5% alcohol by volume (ABV), meaning it's safe for those who have recovered from alcohol addiction, Gillespie says. However, pregnant people should avoid drinking kombucha since it's unpasteurized.
Kombucha may also contain caffeine, but the amount depends on what tea it's made from. Typically, an 8 fluid ounce serving will contain between 8 to 14 milligrams of caffeine, says Vanessa Rissetto, RDN, co-founder of Culina Health.
Kombucha may also offer many health benefits, such as:
1. Contains probiotics
Kombucha's fermentation process produces living organisms called probiotics.
"When consumed, probiotics establish themselves in your gut, and help the existing microbiome [the healthy bacteria in our GI system] digest and absorb nutrients," says Rissetto.
A 2014 study found that kombucha can contain several species of lactic-acid bacteria. Some species play a role in regulating metabolism, as well as helping to control infection and inflammation.
2. High in antioxidants
Since kombucha is made from tea, it can be a rich source of antioxidants. Antioxidants are natural compounds that can help prevent cell damage which can increase your risk of inflammatory diseases - such as arthritis and lupus - certain cancers, and advanced aging, amongst other diseases and conditions.
3. May prevent heart disease
Kombucha made from green tea specifically contains polyphenols, a type of antioxidant.
Research suggests polyphenols may protect against cardiovascular disease by:
- Keeping the inner lining of the heart and blood vessels more flexible, thus helping to regulate blood flow
- Reducing inflammation
- Decreasing bad (LDL) cholesterol.
In fact, a large 2016 study of middle-aged and older Chinese people found that drinking green tea improved multiple risk markers for heart disease, like total cholesterol, HDL-cholesterol, triglycerides, and uric acid. Another large 2006 study of Japanese subjects found that drinking green tea regularly was tied to a reduced risk of death associated with cardiovascular disease.
4. May help manage type 2 diabetes
Kombucha may help stabilize blood sugar levels by slowing the digestion of carbohydrates, says Gillespie. This is a critical aspect of diabetes management.
Findings on this link thus far have been mainly limited to animal studies. However, a large 2009 review found high intakes of tea were associated with a reduced risk for diabetes.
Insider's takeaway
The health benefits of kombucha largely stem from antioxidants in the tea it's made from.
Pregnant and breastfeeding people as well as those that are immunocompromised should avoid kombucha due to the risk of exposure to harmful bacteria, says Gillespie.
Although it's generally considered safe in moderate amounts for healthy individuals with no pre-existing conditions, consuming large amounts can cause unpleasant side effects, like stomach upset, and in very rare cases, serious illnesses, such as liver damage and acidosis. Therefore, it's recommended that you drink a maximum of 4 ounces per day.