The Full Story
Kombucha tea is a beverage, sweetened with sugar and fermented with a so-called "mushroom", a membrane filled with various yeasts and bacteria. The result is a slightly effervescent, slightly alcoholic liquid which might smell and taste like vinegar.
Proponents claim that kombucha tea prevents or treats many health conditions, including cancer, arthritis, high blood pressure, acne, liver disorders, and gastrointestinal disorders. There are no medical studies documenting health benefits. Health professionals cite cases of toxicity, lead poisoning, and even death from drinking kombucha tea.
Kombucha tea often is brewed at home. Sugar is dissolved in black, green, or white tea. Then, a kombucha "mushroom" is added; this thick round disk comprised of yeasts and bacteria causes fermentation. After a period of fermentation ranging from a few to several days, the liquid is drunk as a beverage or health tonic.
Home-brewed kombucha tea has been associated with several adverse health events. These include at least one death, a case of cardiac arrest, several cases of hepatitis, one of severe muscle weakness and inflammation of the heart muscle, and cutaneous [skin] anthrax. Lead poisoning occurred after kombucha tea, which is acidic, was brewed in ceramic containers. None of these cases was attributed to bacterial contamination of the beverage, but authorities warn that contamination is possible if home brewing is not carried out carefully.
In the U.S., kombucha tea has become popular enough that it is sold commercially, especially in health food stores. Some commercially prepared kombucha teas were recalled because the alcohol level was higher than advertised. By law, a product advertised as non-alcoholic may contain no more than 0.5 percent alcohol. Some preparations contained as much as three percent alcohol. It is thought that the beverage continued to ferment in the bottle.
In summary, there are no scientific studies to support the many health claims made for kombucha tea. There are many reasons to be concerned about the safety of kombucha tea, despite its long history of traditional use. It is important that young children, pregnant women, and individuals with compromised immune systems not drink kombucha tea, whether commercially prepared or prepared at home.
Rose Ann Gould Soloway, RN, BSN, MSEd, DABAT emerita
U.S. Centers for Disease Control and Prevention. Unexplained severe illness possibly associated with consumption of kombucha tea – Iowa, 1995. MMWR 1995;44:892-893, 899-900.
Phan TG, Estell J, Duggin G, Beer I, Smith D, Ferson MJ. Lead poisoning from drinking kombucha tea brewed in a ceramic pot. MJA 1998; 169: 644-646.
Kole A SH, Jones HD, Christensen R, Gladstein J. A case of Kombucha tea toxicity. J Intensive Care Med. 2009;24(3):205-7.
Young children, pregnant women, and individuals with compromised immune systems should not drink kombucha tea, whether commercially prepared or prepared at home.
This Really Happened
A 53-year-old college professor was given a kombucha mushroom by a friend; he hoped it would relieve his symptoms of muscle pain and weakness. The man brewed kombucha tea and drank about a half cup twice a day. After two weeks, he developed abdominal cramps and loss of appetite. He stopped drinking the tea. Two days later, he developed a rash. A few days after that, he developed chest tightness and trouble breathing. Also, he noticed that his urine had become dark.
Although the patient had no known risk factors for liver disease, he had developed an enlarged liver and hepatitis, with abnormal liver enzyme studies. Fortunately, his symptoms and his abnormal laboratory results improved over the next month.
Reference: Perron AD, Patterson JA, Yanofsky NN. Kombucha ''mushroom'' hepatotoxicity. Ann Emerg Med. 1995;26:660-661.