Kimchi intake alleviates obesity-induced neuroinflammation by modulating the gut-brain axis

A high-fat diet (HFD) induces low-grade, chronic inflammation throughout the body including the hypothalamus, a key brain region involved in the control of satiety and energy expenditure in central nervous system (CNS). Kimchi is a traditional fermented Korean food, which is recognized as a healthy food. In this study, we evaluated its ability to suppress the obesity-induced inflammation in mice fed an HFD. Male C57BL/6 mice were fed an HFD or HFD with kimchi (pH 5.2 ∼ 5.8). Oral administration of kimchi significantly reduced the body weight, fat mass gain, and levels of pro-inflammatory cytokines in serum. Furthermore, kimchi diminished the HFD-induced activation of astrocyte and microglial cells (reactive gliosis, a hallmark of CNS injury and inflammation) in hypothalamus region. IgG accumulation assay showed that kimchi ingestion suppressed HFD-induced breakage of the blood brain barrier (BBB) via upregulating the expression of tight junction molecules in cerebrovascular endothelial cells. In addition, kimchi modulated gut microbiome profiles, which showed an increase in the abundance of Akkermansia muciniphila. Moreover, kimchi enhanced acetate level and BBB integrity in A. muciniphila-colonized gnotobiotic mice. These results suggest that kimchi may exert beneficial effects to prevent and ameliorate obesity and associated neuroinflammation by changing gut microbiota composition and short-chain fatty acids production.