High β-Glucan Barley Supplementation Improves Glucose Tolerance by Increasing GLP-1 Secretion in Diet-Induced Obesity Mice

Abstract

The aim of this study was to investigate the underlying mechanism for the improvement of glucose tolerance following intake of high β-glucan barley (HGB) in terms of intestinal metabolism. C57BL/6J male mice were fed a fatty diet supplemented with HGB corresponding to 5% of dietary fiber for 83 days. An oral glucose tolerance test was performed at the end of the experimental period. The concentration of short-chain fatty acids (SCFAs) in the cecum was analyzed by GC–MS (gas chromatography–mass spectrometry). The mRNA expression levels related to L cell function in the ileum were measured by real-time PCR. Glucagon-like peptide-1 (GLP-1) levels in the portal vein and cecal content were assessed by enzyme-linked immunosorbent assay. GLP-1-producing L cells of the ileum were quantified by immunohistochemistry. HGB intake improved glucose tolerance and increased the cecal levels of SCFAs, acetate, and propionate. The number of GLP-1-positive L cells in the HGB group was significantly higher than in the control group. GLP-1 levels in the portal vein and cecal GLP-1 pool size in the HGB group were significantly higher than the control group. In conclusion, we report improved glucose tolerance after HGB intake induced by an increase in L cell number and subsequent rise in GLP-1 secretion.

The Role of Short-Chain Fatty Acids of Gut Microbiota Origin in Hypertension

“…Through the GPRs on the surface of intestinal endocrine cells, SCFAs promote the secretion of intestinal hormones, such as glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY; Zhang et al, 2019a;Ren et al, 2020;Wang et al, 2020;Nishida et al, 2021). In particular, GLP-1 enhances glucose tolerance and regulate metabolism (Suzuki and Aoe, 2021), whereas PYY increases satiety, reduces food intake, regulates intestinal movement and slows down gastric emptying to improve body metabolism (Freire and Alvarez-Leite, 2020;Nishida et al, 2021). GPRs affect the influence of gut microbiota on the body's energy, i.e.…”

Arabinoxylan as well as β-glucan in barley promotes GLP-1 secretion by increasing short-chain fatty acids production

“…Increased GLP-1 secretion in the OGTT may be due to increased L-cell counts in the ileum. In our previous study data indicated that high β-glucan barley consumption increased ileal NeuroD and cecal GLP-1 pool size [ 26 ]. The current study shows similar results, suggesting that barley-derived arabinoxylan may also increase L-cell numbers by increasing SCFAs.…”

Consumption of barley flour increases gut fermentation and improves glucose intolerance via the short-chain fatty acid receptor GPR43 in obese male mice

“…Several studies have reported that barley consumption improves blood lipid parameters and glucose tolerance. [6][7][8][9][10] In general, these effects are thought to be due to the increased viscosity of digesta by β-glucan in the digestive tract, forming a gel that reduces the rate of other nutrient absorption. 7 This enhanced viscosity inhibits postprandial glucose spikes and excess insulin secretion.…”

“…We previously reported that mice fed barley contained high-β-glucan levels displayed improved glucose tolerance via increasing L-cell counts and enhanced GLP-1 secretion. 9 Another study reported that mice fed barley flour improved insulin sensitivity via SCFAs, which promote the secretion of intestinal hormones such as GLP-1. 10 However, both studies did not examine the effects of GPR43.…”