Kombucha is a drink that dates back about two thousand years. It's made from tea, sugar, yeast, and bacteria, and now that it has surged in popularity and can be found on store shelves everywhere, there are many purported health benefits. It is typically brewed for about a month, and ends up with light carbonation and a tangy, tart taste that may remind some people of a mild vinegar. It could also contain very low levels of alcohol, about as much as a non-alcoholic beer at roughly 0.5 percent.
The supposedly healthy bacteria that ferment the beverage could affect human health, and might lower blood pressure or help reduce the risk of cancer, but there is not a lot of scientific evidence to back up those claims. Kombucha does contain beneficial antioxidants and polyphenols that could help lower the risk of inflammation, and chronic diseases that can arise from inflammation, such as arthritis or heart disease.
In a new study, scientists have examined what some of the effects of drinking kombucha may be. They exposed a common animal model called C. elegans, which is a nematode worm that has many genes in common with humans, to kombucha or a control diet, and compared the groups.
When they assessed the metabolic impact of kombucha, the researchers determined that the yeast and bacteria from the drink colonize the worms' guts, and promote metabolic changes that are similar to those that occur during fasting, but even while sufficient nutrients were available. Many research studies have found that fasting can have some beneficial health impacts (though research findings in this area are still a bit mixed).
In this study, genes that are associated with the breakdown of fats became more active in kombucha-exposed worms, there was a reduction in triglyceride levels, and lipid droplets also became physically smaller in these worms compared to worms that were eating a diet that did not contain kombucha. The worms seemed to be changing how they stored fat in response to kombucha. The findings have been reported in PLOS Genetics.
While more research will be needed to determine whether kombucha has a similar influence on human metabolism, this research has suggested that kombucha may indeed have beneficial health effects, which may be due to the microbes the drink contains.
Sources: Public Library of Science, PLOS Genetics
