Viscous dietary fibers added to a high fat diet decrease fatty liver, reduce hepatic gene expression of gluconeogenic enzymes and improve metabolic flexibility in obese rats

Abstract

We have previously shown that increasing intestinal contents viscosity with viscous fiber reduces adiposity and improves glucose control in rats fed a high‐fat diet. In this study, we determined the effect of viscous fibers on the development of fatty liver and fuel flexibility in a model of diet‐induced obesity. Rats were fed a high fat diet (60% energy from fat) containing 5% fiber as cellulose (non‐viscous) or one of two highly viscous fibers ‐ hydroxypropyl methylcellulose (HPMC) or guar gum. After 10 weeks of feeding, HPMC and guar groups had lower liver weight, liver lipid and liver cholesterol compared to the cellulose group as well as decreased liver gene expression of the gluconeogenic enzymes G6Pase and PEPCK, indicating decreased fatty liver and reduced gluconeogenesis. Plasma adiponectin, an adipokine that correlates with hepatic insulin sensitivity, was also increased in the HPMC group. RQ was greater during the transition from fasting to fed state in the HPMC (p=0.055) and guar groups, suggesting a quicker shift from fatty acid to carbohydrate oxidation, or greater metabolic flexibility, possibly through improved glucose control. The HPMC group had greater in‐vitro palmitate oxidation in the muscle compared to the cellulose group, implying greater mitochondrial function. Consumption of viscous fibers with a high fat diet can reduce fatty liver and improve metabolic flexibility. Funded by MN Obesity Ctr