Fermented natto powder alleviates obesity by regulating LXR pathway and gut microbiota in obesity rats

Abstract Aim This study aimed to investigate the positive effect of natto powder on obese rats fed with a high-fat diet (HFD). Methods and results Sprague–Dawley rats were fed with a HFD for 8 weeks continuously and gavaged with natto powder, respectively, for 8 weeks starting from the ninth week. The results showed that natto powder significantly reduced the body weight of rats and maintained the balance of cholesterol metabolism in the body by inhibiting the activity of liver X receptors (LXR) target genes, increasing the active expression of cholesterol 7 alpha-hydroxylase, and reducing the active expression of sterol-regulatory element-binding protein and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR). Furthermore, natto powder increased the relative abundance of potentially beneficial microbiota in gut and decreased the relative abundance of obesity-related harmful bacteria, and also increased the Bacteroidetes/Firmicutes ratio and improved the composition of gut microbiota. Conclusions Natto powder maintains the balance of cholesterol metabolism by inhibiting the LXR pathway and regulating the gut microbiota.