Kombucha: Studies Show Risks Outweigh Benefits

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Proponents of kombucha tea claim the drink, created by certain types of fungi and bacteria that contribute to the fermentation of the tea, has anti-cancer properties and can “detox” the body. Kombucha is a type of black or green tea from the plant Camellia sinensis, that is fermented for about a week,  to which certain types of bacteria, fungi and sugars are added. However, the cumulative scientific evidence as well as studies conducted in the past decade show that kombucha drinks’ risks outweigh their benefits.

According to the American Nutrition Association, kombucha is claimed to have originated in China thousands or hundreds of years ago – depending on the source – and has mystical powers to prolong life and improve health. Some even claim that drinking kombucha can treat AIDS, diabetes, obesity and a host of common diseases and disorders. However, none of these claims have been verified.

Examine.com, an independent research organization that reviews various nutritional topics and trends, recently evaluated kombucha and its claims. Although it is rich in antioxidants, there is no evidence to compare it with catechins found in green tea or vitamin C, which have been proven to help reduce the risk of cancer. Examine.com pointed out that kombucha has saccharolactone, which is a bioactive compound that is claimed to “exert anti-cancer effects in the colon.” Even though studies in rats and in vitro have shown that it may have healing properties, saccharolactone is difficult to apply in human subjects for two reasons: No human studies have ever been done on saccharolactone either in kombucha or by itself, and kombucha intake can increase the risk of death if the drink is prepared improperly. Cross-contamination during the production process can increase the growth of certain bacteria and fungi that may cause “cutaneous anthrax” and “acute renal failure,” according to a few reported case studies. With the given evidence available, Examine.com stated that there is no proven and significant benefit of drinking kombucha nor is it very practical as a health supplement, “considering there’s hardly any evidence for its health effects, but plenty of evidence for the damage it can do.”

Not all animal studies show that kombucha compounds’ benefits outweigh their risks. A study on kombucha’s healing effects on lab rats that was conducted at Tehran University’s Department of Pathology in Iran was published in 2013 in Diagnostic Pathology. Rats that were administered kombucha fungus showed better wound healing than those that were given Nitrofurazone, a type of ointment, but the results and differences “were not significant.”

Scott Gavura, BScPhm, MBA, who is a pharmacist and writer, pointed on Science-Based Medicine to a 2003 systematic review that was published in a Swiss journal
(Forsch Komplementarmed Klass Naturheilkd) that did not find any clinical trials or case series in which kombucha had any hint of medical benefits. “Based on what’s known about the active ingredients, there’s no reason to expect it would offer any medicinal effects other than the consequence of low levels of alcohol or caffeine.” Like Examine.com, Gavura listed documentation of toxicity and harm related to kombucha consumption, including hepatitis and metabolic acidosis.

The Kombucha “mother.”

Even though drinking kombucha has risks that outweigh the “benefits,” both Examine.com and Gavura agree that if people like the taste of the product, drink it wisely. Examine.com suggested that consumers purchase kombucha from “trustworthy producers with sanitary working conditions and properly trained staff” to minimize cross-contamination. Gavura said that drinking kombucha “probably won’t kill you.” Considering the lack of documented health benefits, there is no real benefit to consume it unless it is just for the taste. As with any food, Gavura suggested that people should weigh the risks and benefits. In the case of kombucha, it may not be a wise choice for some people.

By Nick Ng


Diagnostic Pathology
Forsch Komplementarmed Klass Naturheilkd
Journal of Medicinal Food
American Nutrition Association

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