Dysbiosis of gut microbiota and its derived metabolites has been linked to the occurrence and development of nonalcoholic fatty liver disease. Our previous study has demonstrated that mung bean coat (MBC) might be mainly responsible for the beneficial effects of whole mung bean on high fat diet (HFD)-induced metabolic disorders. To investigate whether MBC, which is rich in dietary fiber and phytochemicals, can protect against HFD-induced hepatic steatosis in mice via targeting gut microbiota and its metabolites, we conducted this study. Results showed that MBC could effectively alleviative the obese phenotype, reduce the lipid accumulation and insulin resistance, and improve the hepatic oxidative stress and inflammatory response. Furthermore, MBC significantly prevented the HFD-induced changes in the structure and composition of gut microbiota, characterized by promoting the bloom of Akkermansia, Lachnospiraceae_NK4A136_group, and norank_f_Muribaculaceae, and along with the elevated short-chain fatty acids concentrations. Non-targeted metabolomic analysis indicated a metabolism disorder that was obviously improved by MBC via regulating sphingolipid metabolism and α-linolenic acid metabolism. These findings suggested that MBC could improve hepatic steatosis through manipulating the crosstalk between gut microbiota and its metabolites.

Foxtail millet (FM) whole grain has received special attention in recent years. To confirm the hypoglycemic effects of FM, we investigated the effects of FM supplementation on glucose metabolism and gut microbiota in rats with high-fat diet/streptozotocin (HFD/STZ)-induced diabetes. Specifically, we fully assessed the blood biochemical profiles, pancreatic histopathology, insulin-glucagon immunofluorescence, short-chain fatty acids, and gut microbiota composition of rats with HFD/STZ-induced diabetes before and after FM supplementation. Results showed that both 30% and 48% FM supplementation significantly decreased concentrations of fasting blood glucose, 60-min blood glucose, and blood triglycerides (P < 0.05); additionally, 48% FM supplementation significantly improved blood glucose tolerance and insulin resistance (P < 0.05). However, FM supplementation could not effectively repair damage to β-cells over a short period of time. In addition, 4 weeks of 48% FM supplementation siginificantly increased the relative abundance of Bifidobacterium and concentration of butyrate, suggesting that the hypoglycemic effects of FM supplementation might be partially mediated by gut microbiota. Collectively, we found a dose-dependent relationship between FM supplementation and improvement of blood glucose metabolism, but did not find a synergistic effect between FM supplementation and metformin (Met) treatment. Our findings provide further support that consuming more whole-grain FM might be beneficial to individuals suffering from type 2 diabetes.