WebMD questioned the safety of kombucha in an article this week so World Tea News spent some time exploring this unusual beverage.
The process of making kombucha involves fermenting tea leaves for 7-10 days with a mix of live cultures called a SCOBY or “symbiotic culture of bacteria and yeast” and sugar. The resulting beverage, popular in Asia for centuries, is effervescent with slightly sour, tangy flavor. The drink is also rich in probiotics and vitamin B. In the WebMD article, Michelle Crowder, a naturopath at Grosse Pointe, Mich.’s Beaumont Hospital, said that mental health and fermented foods are “a very active and exciting area of research.” She also credits the connection between B vitamins and a healthy nervous system. She does, however, caution that some of the benefits may not be as powerful as advertised. Dr. Brent Bauer from the Mayo Clinic states that there is no scientific evidence that prove kombucha’s benefits. Andrea Giancoli from the Academy of Nutrition and Dietetics agrees.
This isn’t the first time kombucha has faced perception and marketing troubles. The U.S. Alcohol and Tobacco Tax and Trade Bureau issued warnings because of its alcohol content. The alcohol, generally less than 0.5%, is a by-product of the fermentation process, but some kombucha on the shelves was testing higher. Producers were told to tweak their formulas or fines would be imposed. The reality is that the alcohol levels can become higher if the kombucha is not stored at cold enough temperatures because fermentation continues. Whole Foods Market pulled the product from its shelves noting that some of the kombucha reached 3% alcohol. Commercial producers changed formulas to prevent additional fermentation and storage processes were reassessed.
So, the benefits are not fully proven with scientific research—but is it safe? The challenge with kombucha is in the intervention. If there is benefit to kombucha, it would be from the probiotics. That would mean raw or unpasteurized would be preferred, because probiotics and pasteurization don’t mix (pasteurization kills bacteria, breaks down some helpful components). But this is also the kombucha that has the highest risk. Molds resulting from fermentation can result in allergic reactions and unpasteurized beverages can carry pathogens. Two women became very ill from an unsafe SCOBY source and one eventually died. While the connection to the kombucha wasn’t proven, it raised concerns.
As a result, the CDC suggests limiting consumption to only 4 ounces a day. There are also recommendations that young children, pregnant women and those with immune system vulnerabilities should avoid drinking it completely.