Viscous dietary fibers improve glucose control, reduce fatty liver and decrease lipogenic gene expression in ZDF rats

Viscous fibers decrease the postprandial rise in blood glucose and reduce plasma cholesterol. We previously demonstrated that viscous fibers increase intestinal viscosity which leads to improved glucose control in Zucker Diabetic Fatty (ZDF) rats. The purpose of this study was to determine the effect of increasing intestinal viscosity with the fibers hydroxypropyl methylcellulose (HPMC) and β‐glucan on the development of fatty liver in this obese diabetic rat model. ZDF rats were fed a diet of either 5% non‐viscous cellulose, 40% low viscosity (LV) β‐glucan flour (Sustagrain), 5% medium viscosity HPMC or 5% high viscosity (HV) HPMC. After 6 weeks of feeding, the LV and HV HPMC groups had reduced liver total lipid, decreased liver cholesterol and reduced liver weight compared to the other ZDF groups. HV HPMC feeding did not affect the liver mRNA expression of SREBP‐1c or ACC1 but did reduce FAS mRNA expression, suggesting that decreased lipogenesis may contribute, in part, to reduced liver lipids by HPMC. Gastrocnemius mRNA expression of PGC1α, CPT1b and UCP3 was not different, nor was adipose PPARγ protein expression, implying that intestinal viscosity did not affect muscle fatty acid oxidation or adipogenesis. These results indicate that improved glucose control and reduced fatty liver by viscous fiber may be due to decreased liver lipogenesis in ZDF rats. (Supported by the MN Agric Exp Station)