Note to Reporters: The following column was written by Melissa Wdowik, an assistant professor at Colorado State University in the Department of Food Science and Human Nutrition, and director of the Kendall Anderson Nutrition Center.
On a recent trip to the South, my family enjoyed the availability of sweet tea at every turn. It made me think about the health benefits of tea – a common hot beverage in our house – and possible cold alternatives to the sticky syrupiness of sweet tea. Observing the popularity of kombucha tea, I wondered if this could be the healthful alternative I was looking for.
Kombucha is a tart, bubbly beverage produced when tea is brewed, steeped with sugar, and then fermented by a group of bacteria and yeasts. Fermentation forms a “kombucha mushroom," which is not really a mushroom, but is actually a symbiotic colony of bacteria and yeast, or “SCOBY.” The yeast produces alcohol from the sugar, then the bacteria acts on the alcohol to produce the fizzy beverage.
The taste has been described as tangy, flavorful, or acidic. There is no arguing that you can smell and see the “mushroom,” which may or may not be appealing to you. There are a myriad of drink variations, including black, green, white, or oolong tea; caffeinated or caffeine-free tea; and the addition of fruit, juice, herbs, and spices.
Are there health benefits? Thousands of years ago in eastern Asia, kombucha was believed to boost immunity. Other health claims include its ability to rid the body of toxins, improve digestion, enhance skin and hair appearance, improve liver function, reduce headaches, and prevent or treat cancer. Unfortunately, there are no clinical studies and no scientific evidence that any of these claims are true. Kombucha does contain probiotics, or beneficial bacteria that may improve the immune system. There are risks, however, including foodborne illness. This is a significant concern for homemade tea because it is fermented at room temperature for seven to 12 days and is a favorable environment for the growth of harmful bacteria. Another risk is the possibility of using contaminated yeast and bacteria, which produce molds and fungi that can cause illness. Reported side effects of drinking homemade kombucha include stomach aches, allergic reactions, and even death in a case where contaminated SCOBY was used. Contamination is less of a concern in commercial teas produced under controlled conditions.
Another problem is alcohol content. Some commercial teas have been found to have alcohol content as high as 3 percent, higher than what is allowed by the FDA. Some home-brewed kombucha has been reported to have even higher alcohol content.
It may be fine to consume a beverage if you like it and feel it is helping you, as long as you experience no negative side effects. For my family, I have decided to stick with brewed iced green tea, since there is ample evidence of green tea health benefits. Frankly, I don’t have the patience to wait a week to quench my thirst. For the rest of you, weigh the pros and cons, and proceed with caution.
Melissa Wdowik is an assistant professor at Colorado State University in the Department of Food Science and Human Nutrition, and director of the Kendall Anderson Nutrition Center.