Effect of low glycaemic index diet on the glucose and lipid metabolism, microbiota composition, short-chain fatty acids content, immune response, and FGF-19 and CYP7A1 levels in type 2 diabetes rats

Abstract

More and more evidence has showed that low glycaemic index (GI) diet was a benefit to the Type 2 Diabetes Mellitus (T2DM). However, the detailed mechanism was not clear. Here, we detected the effects of low-GI diet on the HFD/STZ-induced T2DM rats model. Our results showed that low-GI diet significantly decreased triglyceride and glucose level in the serum of T2DM rats, and increased the level of insulin and C-peptide in T2DM rats. Besides, low-GI diet also increased Bacteroidota at the phylum level. And at the genus level, low-GI diet promoted the proliferation of the abundance of Turicibacter, Lactobacillus, Desulfovibrio, Prevotellaceae, Lachnospiraceae, Monoglobus, Xylanophilum and Roseburia. Moreover, we also found that low-GI diet significantly improved the contents of valeric acid, acetic acid, propionic acid, isobutyric acid, butyric acid, 2-methylbutyrate, isovaleric acid, 4-methylvaleric acid and hexanoic acid; upregulated the levels of peptide YY (PYY), glucagon-like peptide 1 (GLP-1) and G protein-coupled receptor 41 (GPR41); and increased the numbers of L-cells (P < 0.05). Additionally, low-GI diet significantly decreased the content of interleukin 6 (IL-6); increased the contents of transforming growth factor-β2 (TGF-β2) and fibroblast growth factor 19 (FGF-19); and enhanced the activity of cholesterol 7α-hydroxylase (CYP7A1) (P < 0.05).

Keywords

• Low-glycemic index diet
• T2DM
• Gut microbiota
• Short-chain fatty acids
• Immune response