Green Tea Ameliorates Depression‐Like Behavior and Cognitive Impairment Induced by High‐Fat Diet and Chronic Mild Stress

Depression often develops in young individuals and is linked to complications like cognitive impairment. Conventional antidepressants show limited efficacy in restoring cognitive function and may cause adverse effects. Green tea, a safe and health-promoting beverage, offers various health benefits. This study investigated the effects of long-term green tea consumption on stress-induced depression-like behavior and mild cognitive impairment in animal models. We established a rodent model of mild depression and studied the effects of green tea on depression-like behavior and cognitive impairment through comprehensive evaluation, including behavioral assessments, neurotransmitter quantification, gene and protein expression analysis, blood metabolite profiling, and gut microbiota characterization. Results demonstrated significant improvements in mood, long-term memory, and sterol and glycerophospholipid metabolism. Green tea repaired the intestinal barrier and upregulated genes vital for tight junctions and mucin production. It also enhanced gut microbiota composition, reducing the Firmicutes-to-Bacteroidetes ratio and promoting beneficial bacteria such as NK4A136, Muribaculum, and Gordonibacter. These microbiota changes improved liver lipid metabolism and alleviated depressive symptoms. Green tea effectively mitigates depression-like behavior and cognitive deficits by modulating the gut-liver-brain axis.