Kombucha: a systematic review of the empirical evidence of human health benefit

Purpose: Kombucha tea, a fermented beverage, has recently become popular in the United States as part of the functional food movement. This popularity is likely driven by its touted health benefits, coupled with the recent scientific movement investigating the role of the microbiome on human health. The purpose of this systematic review is to describe the literature related to empirical health benefits of kombucha as identified from human subjects research. Methods: In July 2018, we searched the term "kombucha" for all document types in the following databases across all available years: PubMed, Scopus, and Ovid. To identify federal research grants related to kombucha, we searched the National Institutes of Health Research Portfolio Online Reporting Tools. Finally, to identify ongoing human subjects research, we searched clinicaltrials.gov and clinicaltrialsregister.eu. We reviewed a total of 310 articles. Results: We found one study reporting the results of empirical research on kombucha in human subjects. We found no results for kombucha in Research Portfolio Online Reporting Tools, clinicaltrials.gov, or clinicaltrialsregister.eu. Conclusions: The nonhuman subjects literature claims numerous health benefits of kombucha; it is critical that these assertions are tested in human clinical trials. Research opportunities are discussed. (C) 2018 The Authors. Published by Elsevier Inc.