Health effects and probiotic and prebiotic potential of Kombucha: A bibliometric and systematic review

Kombucha is a fermented beverage composed of a range of natural compounds such as sugars, ethanol, organic acids, and complex microbial communities of bacteria and yeasts. Based on this several biological properties are attributed to this drink. However, the production of kombucha is not standardized and the final composition of the beverage is highly dependent on the raw materials used and the physicochemical parameters adopted in the process. As a consequence, kombuchas not only vary from one producer to another but also from different batches of the same producer, making the assumptions of quality and properties questionable. In this review, we explore the largely unchecked relations between kombucha and its claimed health benefits. A systematic review was also performed to specifically discuss the potential probiotic and prebiotic effects of kombucha. Although several studies report that kombucha present antimicrobial, antioxidant, detoxifying, and hepatoprotective activities, among others, whereas others classify kombucha as a probiotic drink, there is a lack of scientific evidence about the content of probiotics in this drink and its possible role in the intestinal microbiota. These facts highlight the opportunities in researching and modifying the microbiome composition of kombucha, possibly improving the general qualities of this so-called functional drink.