You Asked: Can “Kombucha tea” prevent the flu?

teaWhile some people are looking to stockpile Tamiflu in case the bird flu strikes, a few others are placing their bets on a foul concoction with a folkloric history of curing everything from AIDS and baldness to flatulence and cancer. Kombucha tea is brewed by incubating a culture of bacteria and yeasts in sweetened black or green tea. The microbial culture, which is passed from believer to believer, ends up floating on top of the tea and resembles a mushroom, which is why sometimes the concoction is referred to as the Kombucha mushroom.

The argument is that the metabolic products produced by this magical blend of microbes have antibiotic and immune system boosting properties. Anecdotes abound about the healing abilities of this “Miracle Fungus” and the feeling of well-being it produces. But in the world of science, that doesn’t amount to a hill of beans. If the sweat of three-legged Himalayan virgin donkeys were advertised as a cure-all, there would be plenty of anecdotal evidence for efficacy as well.

So what does science say about the possible medicinal effects of Kombucha? Well, there is not a whole lot of optimism expressed. But that is not to say that there is no possibility for physiological action. Lead, for example, is known to depress the immune system. When rats are administered an oral lead solution, followed by Kombucha tea, the level of immunosuppression is reduced. Kombucha has also been shown to elevate the levels of glutathione, an important immune booster, in the blood of rats exposed to cold temperatures. Furthermore when rats are given high doses of the pain killer acetaminophen, they show less liver damage when treated with Kombucha tea. In the laboratory, Kombucha extracts show activity against a variety of bacteria.

All of that sounds kind of hopeful, but test tubes and rats are a long way from humans. A thorough search of the medical literature for any studies attesting to the efficacy of Kombucha tea draws a blank. But a search for side effects does not! There have been unexplained instances of severe illness after drinking the tea, including the possibility of at least one death, albeit only after consuming the tea daily for two months. Occasional allergic reactions, liver toxicity, nausea and vomiting have been reported. Two cases of lead poisoning occurred when the fermenting beverage, which is quite acidic, was brewed in a ceramic pot that had a lead glaze. There is also concern that disease causing bacteria or fungi can contaminate the concoction as it is fermenting. Aspergillus is a potentially toxic mould that has been found in the Kombucha microbial mixture. Perhaps Kombucha does merit some further study, but it most assuredly is not the “Cure-All” its proponents claim it to be. There is admittedly not a whole lot of evidence that antiviral drugs such as Tamiflu or Relenza would be effective against the feared avian flu, but there is zero evidence that Kombucha tea has any therapeutic value in humans, unless of course, if you think it does. The placebo effect may make you feel better, but it will not kill viruses.

Joe Schwarcz

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