Kombucha is an effervescent drink made through the fermentation of a sweetened tea. The SCOBY, symbiotic culture of bacteria and yeast, consumes the sugar, producing an acidic end product.
There are few studies of kombucha’s effects across time and in large populations. Kombucha is generally regarded as safe for daily consumption; some individual cases of negative effects such as upset stomach or allergic reaction have been reported. Kombucha tea has strong antioxidant properties. In a study of rats fed lead, kombucha tea decreased DNA damage and diminished the immune-damaging effects of the lead. Analyses of kombucha have found it to be an excellent source of multiple essential vitamins and minerals. The polyphenols found in tea (used for kombucha) are degraded during fermentation.
While the bacterial culture’s metabolism of the starter tea’s sugar primarily results in the production of acetic acid, trace amounts of alcohol may occur in the final kombucha. Commercial producers test this level as part of standard quality control. Individuals concerned with alcohol consumption however should make an informed decision.