Though the maker of GT’s has credited kombucha with helping heal breast cancer, and others have claimed that kombucha helps with stimulating the immune system, hair growth, and other ailments, health experts agree that there is no scientific backing to support such claims. The American Cancer Society notes that no scientific evidence supports these health claims. (Dr. Andrew Weil and Mayo Clinic internist Dr. Brent A. Bauer have indicated similar positions.) Academy of Nutrition and Dietetics Spokesperson Andrea Giancoli, M.P.H., R.D., who specializes in healthful shopping and vegetarian eating concurs. “If you’re drinking kombucha because you think it’s going to cure cancer and fight all kinds of disease, it probably won’t," she says. "There’s really no evidence that it has any of these benefits yet.”
Though few studies have been completed on kombucha’s health benefits, a Cornell University study concluded that “Kombucha may be a healthful beverage in view of its anti-microbial activity against a range of pathogenic bacteria.”
However, both Giancoli and Dr. Daphne Miller, author of
The Jungle Effect: Healthiest Diets From Around The World
note that choosing different sources of these nutrients — for example, an unsweetened yogurt as a source of probiotics, protein and calcium, or fermented veggies such as sauerkraut, for obtaining lactobacillus and other beneficial bacteria — can serve as more nutritious options in the long run, as these options contain less sugar and empty calories.
According to beverage industry publication, BevNet, some kombucha makers question their competitor’s nutritional labeling, saying that that actual sugar levels, bacteria types, and number of organic acids included in the drink aren’t accurately reported. Others think that some companies’ brews secretly use forced carbonation. As of now, there isn’t even a legal definition of what constitutes “kombucha.”
While kombucha has been linked to a few deaths — in 1995, two women who shared the same kombucha starter died of cardiac arrest, for example — the bottled tea is safe for most people to consume. Though those worried about safety may want to steer away from home brews, according to Giancoli, who notes that the acidity of the drink can leach out metal compounds. (She cites a case in which home brewers used a ceramic pot with a lead in the glaze and contracted lead poisoning.)