Fermented walnut milk alleviates high-fat-diet-induced obesity in mice via modulating gut microbiota and lipid metabolism

Plant-based products represent promising alternatives to animal-derived foods, offering solutions to health and environmental challenges. This study evaluates the lipid-lowering effects of fermented walnut milk and elucidates its underlying mechanisms using a high-fat diet (HFD)-induced obesity mouse model. Results demonstrated that fermented walnut milk significantly improved the physical (food intake, body weight, fat index) and biochemical indicators (blood lipid profiles, liver damage biomarkers) compared to animal-based fermented milk in HFD mice. It effectively alleviated pathological changes in the liver and adipose tissue, while enhancing intestinal mucosal integrity in the colon and ileum. Moreover, fermented walnut milk markedly reshaped gut microbiota by increasing the abundance of beneficial bacteria (Dubosiella, Romboutsia, Lactobacillus, Bifidobacterium, etc.), negatively associated with obesity, and decreasing harmful bacteria (Faecalibaculum, Erysipelotrichaceae, Acetatifactor, etc.), positively correlated with obesity. Additionally, it significantly elevated short-chain fatty acid levels (acetic acid, isohexanoic acid, hexanoic acid). In conclusion, fermented walnut milk emerges as a promising functional plant-based product for mitigating obesity and gut microbiota dysbiosis induced by a high-fat diet, providing new insights for dietary intervention strategies.