Wednesday, March 17, 2010
The curious case of Kombucha tea
Clearly, I am favorable to natural non processed foods. However, I also like to distinguish between popular beliefs and scientific evidence.
Non all probiotic foods are healthy. For example, it is easy to find scientific articles describing the link between kefir consumption and decrease of several types of cancer (e.g., Parvez et al., 2006). Kefir is a fermented milk that produces something similar to yogurt. It tastes a little alcoholic and it is known to have many health benefits. To give you an idea the search for "kefir+cancer" on a database such as pubmed gives you immediately more than 100 results.
Another popular beverage is Kombucha tea, which is supposed to have medical properties. I personally had a curious experience with kombucha, which dates back to when I was 9. At that time I used to live in a very superstitious little town, where somebody started spreading a rumor about magic properties of this tea. Specifically, I was told that when the fungus reproduced you could express a desire, which would have become true if you found three (not surprisingly number 3) people to give the plant to. I had it at home for a while and who gave it to me recommended to feed the fungus with commercial tea—which produced a disgusting smell but made the fungus really happy—and even talk to it. After a couple of months, another rumor spread: the fungus was in fact the incarnation of Satan! That, of course, given my catholic education, freaked me out and the next thing I remember is me burning the fungus in the country, which was not easy, as you can imagine.
Back to science, the association of Kombucha and the Devil is unfortunately appropriate. Indeed, there is little if no scientific evidence of its health benefits (Murugesan et al., 2009; but see Greenwalt, Steinkraus, & Ledford, 2000 for a review), while there are several well documented cases of intoxication, sometimes letal (the most recent is SungHee Kole et al., 2009), following ingestion of that beverage.
Kombucha tea is fortunately hard to find in regular groceries stores, but is highly available both online and in health stores.