ABSTRACT
Oat ß-glucan consumption is linked to reduced risk factors associated with diabetes and obesity by lowering glycemic response and serum level of low-density lipoproteins. The purpose of this study was to identify the mechanism of action of oat ß-glucan at the interface between the gut wall and the lumen responsible for attenuating glucose levels. We proposed that viscous oat ß-glucan acts as a physical barrier to glucose uptake in normally absorptive gut epithelial cells IEC-6 by affecting the expression of intestinal glucose transporters. Concentration and time-dependent changes in glucose uptake were established by using a nonmetabolizable glucose analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-d-glucose. The effectiveness of nutrient transport in IEC-6 cells was shown by significant differences in glucose uptake and corresponding transporter expression. The expressions of glucose transporters sodium-glucose-linked transport protein 1 (SGLT1) and glucose transporter 2 (GLUT2) increased with time (0-60 minutes) and glucose levels (5-25 mmol/L). The suppression of glucose uptake and SGLT1 and GLUT2 expression by increasing concentrations (4-8 mg/mL) of oat ß-glucan demonstrated a direct effect of the physical properties of oat ß-glucan on glucose transport. These results affirmed oat ß-glucan as a dietary agent for minimizing postprandial glucose and showed that modulating the activity of the key intestinal glucose transporters with oat ß-glucan could be an effective way of lowering blood glucose levels in patients with diabetes.
