If you haven’t tried it, you’ve at least heard of it. Kombucha – a beverage made of sweet tea fermented with yeast and bacteria – is the latest drink touted to improve your health.
Sales of the tart, effervescent drink have risen by double digits over the past several years. Popular media have touted its wide range of benefits including improving digestive health, reducing your risk of developing cancer and infections, reducing liver toxins and even improving your mental health.
Those are a lot of amazing claims, but what does the evidence say? It turns out that most of the studies on kombucha have been conducted in petri dishes or with laboratory animals. These types of studies offer researchers some idea about potential benefits in humans, but do not provide definitive evidence.
Researchers from the University of Missouri published a systematic review last fall that looked at the health benefits of kombucha in actual human subjects. They found no randomized, controlled trials examining the health benefits of kombucha. (A randomized, controlled trial randomly assigns participants into an experimental group and a control group that does not receive the intervention. It is considered one of the best ways to determine the effectiveness of an intervention or treatment.
They did identify one study conducted by researchers in India that looked at the effects of kombucha on blood sugar levels. Although they found that consuming kombucha did help to stabilize blood sugar levels in diabetic participants who were not dependent on insulin to control their diabetes, they did not include a control group.
The review also includes anecdotal reports of people who experienced health problems that appear linked to kombucha, including a 47-year-old woman who was hospitalized due to liver inflammation after drinking kombucha daily for two years. The researchers caution that these reports are single cases and not part of a larger study, but they do raise the question of whether kombucha is safe for everyone.
If kombucha does offer health benefits, it is most likely related to fermentation, which preserves foods by using microorganisms to convert carbohydrates to acids or alcohol. Some medical researchers hypothesize that these microorganisms are missing from the diets of most Americans and provide health benefits beyond what we currently understand.
While that may be the case, there is not a solid body of evidence that demonstrates fermented foods provide specific health benefits. (There are some data that show fermented dairy products such as yogurts and cheeses can help reduce the risk of cardiovascular disease.)
So, what’s the take-home message? It’s unlikely that drinking kombucha is unhealthy, but there is not clear evidence that it will improve your health either. Overall, consuming fermented foods may provide protection against developing some diseases, but the evidence is not conclusive.
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