Kombucha, a fermented tea beverage, is made by combining tea with a starter-culture of beneficial bacteria and yeast. Kombucha, both commercially prepared and home-brewed, is consumed for its purported health-boosting properties and mild fizziness that, for health-conscious individuals, serves as a welcome replacement for carbonated soft drinks. Some health claims for kombucha have been supported by research; however, controversy persists over kombucha's safety.
Antibiotic
Kombucha effectively kills a variety of pathogenic bacteria, according to a study conducted at the Department of Applied Microbiology and Gene Technology, TNO Nutrition and Food Research Institute, Zeist, The Netherlands and reported in 2000. The researchers believe the high acid level of kombucha is partly responsible for kombucha's antimicrobial effects, as many pathogenic bacteria cannot live in acidic conditions. However, in a study published in the June 2000 "Journal of Food and Agricultural Chemistry," kombucha was effective at killing at least five bacterial species, even when it was altered to be neutral instead of acidic. These researchers concluded their study suggests the presence of other factors in kombucha, besides its acid content, that may be responsible for its antibiotic effects.
Antioxidant and Immune-Enhancing
Potent antioxidant and immune benefits of kombucha were observed in a study on laboratory rats exposed to a toxic compound, conducted at the Defence Institute of Physiology Allied Sciences, Delhi, India. In the study, published in the July 2000 "Journal of Ethnopharmacology," kombucha completely reversed the damage induced by the toxin, according to the researchers. While activity levels of antioxidants increased in response to the toxin, kombucha-treated animals did not show a significant reduction in antioxidant levels, implying that kombucha helped to maintain the antioxidant status. Additionally, kombucha enhanced the antibody response of the immune system.
Anti-Stress and Liver-Protective
Kombucha tea demonstrated anti-stress and liver-protective properties in an Indian study published in the September 2001 "Biomedical and Environmental Science." In the study, conducted at the Defence Institute of Physiology and Allied Sciences, Delhi, India, laboratory rats were fed kombucha for 15 days and then exposed to behavioral and chemical stressors. Animals given kombucha tea showed significantly fewer signs of stress, such as damaged lipids, depletion of glutathione -- an important antioxidant used by the liver -- and elevated levels of certain liver enzymes that indicate stress on the liver, than control animals that did not receive kombucha. Additionally, in behavioral stress tests, kombucha-treated animals showed greater adaptability.
Warnings
The health risks of kombucha outweigh its benefits, according to a U.K. study conducted at Peninsula Medical School, Universities of Exeter and Plymouth, U.K., and published in the 2003 "Research in Complementary Medicine" journal. The meta study, which is a review of previously published literature, found no clinical studies on the effectiveness of kombucha in humans. However, the study cites case reports on possible liver damage, infections and other problems, as well as one fatality, associated with kombucha consumption.
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