Effect of kombucha soymilk on high fat diet mice: integrated insights from gut microbiome and metabolome analyses.

Introduction: Kombucha, soymilk, and tea-derived bioactive compounds have individually been associated with metabolic benefits, while the effects of kombucha soymilk on diet-induced hyperlipidemia and its associated gut microbiome-metabolome changes remain unclear. Methods: In this study, we established a high-fat diet (HFD)-induced obese mouse model and administered kombucha soymilk as a dietary intervention. We systematically investigated the effects on body weight gain, lipid levels, and hepatic antioxidant capacity, and further explored the associated changes in gut microbiota composition and key metabolites underlying its lipid-lowering effects. Results and discussion: Biochemical and histological analyses revealed that kombucha soymilk consumption significantly attenuated body weight gain in mice (p< 0.05), reduced serum and hepatic triglyceride (TG) and total cholesterol (TC) levels (p < 0.01), enhanced hepatic antioxidant capacity, and ameliorated hepatic steatosis. Microbiome analysis revealed that kombucha soymilk consumption altered the gut microbial community structure in mice, increasing the relative abundances of Enterococcus, Bifidobacterium, and Turicibacter. Untargeted metabolomics further suggested altered enrichment of pathways related to pyruvate metabolism, linoleic acid metabolism, bile secretion, and cAMP signaling. In conclusion, kombucha-fermented soymilk improved hyperlipidemia-related phenotypes in HFD-fed mice and was associated with selective gut microbial and metabolic alterations. These findings support its potential as a functional dietary intervention, although the mechanistic interpretation remains exploratory and requires further validation.