Effects of oat beta-glucan, oat resistant starch, and the whole oat flour on insulin resistance, inflammation, and gut microbiota in high-fat-diet-induced type 2 diabetic rats

This study was aimed to compare the beneficial effects of oat beta-glucan (OG), oat resistant starch (ORS), and whole oat foods (WO), and explore the correlations between the key phylotypes of gut microbiota and type 2 diabetes (T2D) indexes and inflammation indexes in high-fat diet induced T2D rats. WO exhibited better effects on ameliorating insulin resistance and glucose tolerance than OG and ORS (p < 0.05). The three oat products had equal effects on the inhibition of cytokine release (p > 0.05). OG, ORS, and WO altered the gut microbiota composition with increased genus Clostridium, and Butyricoccus, but decreased genus Bacteroides, Lactobacillus, Oscillospira, and Ruminococcus. In addition, the Pearson correlation analysis showed that genus Bacteroides, Butyricoccus, Parabacteroides, Lactobacillus, Oscillospira, Ruminococcus, and Bifidobacterium positively correlated (p < 0.05) with the development of diabetes and inflammation, while genus Clostridium and Faecalibacterium showed a negative correlation (p < 0.05). These results provide valuable information about the beneficial effects of oat products on human health.