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Kombucha Tea, Healthy Drink or Hazardous Hoax?

Kombucha tea

If you are among the countless number of people who have stared with uncertainty and trepidation at a batch of kombucha tea and wondered whether you were looking at a healthy drink or a hazardous hoax, you are not alone. You can find people who believe one way or the other, so let’s see if we can’t get some answers here.

What is kombucha tea?

Kombucha tea, which is also sometimes called mushroom tea or Manchurian mushroom, is a fermented beverage prepared using black tea (some use green tea, and both are good sources of antioxidants), sugar, yeast, and bacteria. The word “mushroom” when talking about kombucha tea refers not to the fungi but to the shape of the colony of yeast and bacteria that forms during fermentation.

The colony is a SCOBY—symbiotic colony of bacteria and yeast—and it is responsible for transforming the sweet tea into the final fizzy product that has a tart, mildly sweet, sometimes vinegary flavor.

Is kombucha tea safe?
Here is where individuals and experts disagree. Some say the beverage can make you experience nausea, vomiting, headache, allergic reactions, and even develop an infection. A portion of these claims may be associated with the fact that it is popular to make your own kombucha tea, and the preparation methods may be less than ideal and outright unsanitary in some cases.

To make homemade kombucha tea, you add a portion of SCOBY, which people can get from someone else who has a “mushroom” mother, and add it (a “baby”) to sweetened black or green tea. The mixture is left to ferment in a glass or ceramic container, unrefrigerated, for about ten days. (Note: The acids produced by fermentation may cause lead to leach out of ceramic containers and into the tea.)

The result will be your own SCOBY and billions of bacteria—some of which may be beneficial and some of which may not--swimming in your homemade brew. In fact, according to Andrew Weil, MD, best-selling author and founder/director of the Arizona Center for Integrative Medicine in Tucson, some home-brewed batches of kombucha tea contain a toxin-producing fungus called aspergillus, which is commonly found in the environment and can be hazardous to anyone with a compromised immune system.

Weil noted there have been cases of individuals who developed serious liver conditions after consuming kombucha tea. In addition, he warned that children, the elderly, pregnant or nursing women, and anyone with weakened immune function should avoid drinking kombucha tea, and that overall the beverage has no health benefits.

For those who are curious about kombucha tea but don’t want to make their own, there are commercial brands available. If you decide to choose a branded kombucha tea, be sure to look for those that have been tested for the presence of beneficial bacteria (see "Commercial kombucha tea").

Beneficial bacteria, also known as probiotics, have been studied extensively for their potential role in managing various diseases and health problems ranging from diarrhea to colic and the flu. However, research into the health benefits of kombucha tea and its probiotic potential is scarce.

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Studies of kombucha tea
Thus far, studies of kombucha tea have been done in animals. Although the results do not support some of the claims made by kombucha tea advocates (e.g., that the beverage improves digestion, promotes liver function, helps prevent cancer, stimulate the immune system), the findings are worth a look.

For example, a study in the October 2013 issue of Food and Chemical Toxicology reported on the antioxidant and antidiabetes impact of kombucha tea versus unfermented black tea in diabetic rats. The scientific team discovered that the rats given kombucha tea demonstrated better antidiabetic and antioxidant benefits than those who got the regular black tea, a finding that the scientists noted “might be due to the formation of some antioxidant molecules during fermentation period.”

Another 2013 study explored the impact of kombucha tea on the liver. This study also was conducted in animals and tried to identify the strains of yeast and bacteria that may provide protective benefits for the liver, which is one claim made about the tea.

The researchers did identify a “potential functional strain” that produces a substance, which “might be the key functional component for the hepatoprotective property” of kombucha tea. However, this is still a long way from verifying that kombucha has factors that can protect the human liver.

Commercial kombucha tea
In 2010, some brands of kombucha tea were pulled from the shelves after it was discovered they had an alcohol content of slightly more than 0.5 to more than 2.5 percent. Any beverage with an alcohol content of more than 05 percent is under the watchful eyes of the Alcohol and Tobacco Tax and Trade Bureau, so the makers of these kombucha products had raised eyebrows.

After voluntary withdrawal of kombucha products from the market, tea makers modified their formulas and brewing processes, including a boost in probiotic levels and use of de-alcoholizers. However, some kombucha products retained their alcohol levels and are considered low-alcohol beverages. These are marketed and sold to individuals of legal drinking age.

Commercial kombucha beverages are available in a variety of flavors, including citrus, strawberry, grape, and ginger. Check out the nutritional labels for those that offer the best in terms of nutrients, including probiotics (look for at least 1 billion colony forming units [CFUs] and two or more bacteria species), antioxidants, and vitamins.

The bottom line
Kombucha tea continues to be a popular beverage among individuals who believe it has health benefits. For now at least, scientific evidence to support these beliefs is lacking.

Making your own kombucha tea can be risky. Although ardent homebrewers of kombucha tea will likely not agree, it is likely safer to consume commercially prepared kombucha tea--which may have proven probiotics and other beneficial ingredients--than to go the homemade route.

Bhattacharya S et al. Effect of kombucha, a fermented black tea in attenuating oxidative stress mediated tissue damage in alloxan induced diabetic rats. Food and Chemical Toxicology 2013 Oct; 60:328-40
Wang Y et al. Hepatoprotective effects of kombucha tea: identification of functional strains and quantification of functional components. Journal of the Science of Food and Agriculture 2013 May 28

Image: Wikimedia Commons