Kombucha Tea-associated microbes remodel host metabolic pathways to suppress lipid accumulation

Author summary Kombucha is a popular fermented tea that has been purported to have many human health benefits, including protection against metabolic diseases like diabetes and obesity. These health benefits are thought to be conferred by the probiotic microbes found in Kombucha Tea, which includes both bacterial and yeast species, that may be able to colonize the human intestine and alter host physiology. The mechanisms by which the Kombucha Tea-associated probiotic microorganisms (KTMs) impact host physiology are largely unknown. Using the nematode Caenorhabditis elegans as an animal model system to study the host physiological response to KTMs, we show that KTMs colonize the C. elegans intestine and impart widespread changes in the expression of evolutionarily conserved lipid metabolism genes, resulting in reduced fat levels in the host. The host metabolic response to actively fermenting KTMs requires an increase in proteins that break down lipids paired with a reduction in a protein that builds triglycerides, which mirrors the events that occur during fasting. These findings are consistent with the reported human health benefits of Kombucha Tea and provide new insights into the host response to Kombucha-associated microbes, which could inform the use of Kombucha in complementary health care approaches in the future.