Dietary Rapeseed Oil Supplementation Reduces Hepatic Steatosis in Obese Men

Abstract

Obesity is associated with nonalcoholic fatty liver disease (NAFLD) leading to increased hepatic glucose production. NAFLD is one of the most frequent liver diseases however, effective treatment is limited. Animal studies showed a reduction in hepatic steatosis with dietary alpha linoleic acid, which is highly enriched in rapeseed oil (RA). In this study we used a nutritional therapeutic approach and investigated the effect of an isocaloric diet supplemented with RA or olive oil (OL) on liver fat content, endogenous glucose production, total body insulin sensitivity and serum lipids in obese humans suffering from NAFLD. 27 obese men (BMI 30-35, age 18-65) consumed an isocaloric diet including 50 g of either RA (n=12) or OL (n=15) daily for eight weeks. Hepatic MRI, hyperinsulinemic-euglycemic clamp studies with isotope labelled glucose and blood tests were performed prior to and at the end of the study to assess liver fat content, endogenous glucose production and cholesterol and free fatty acid levels, respectively. Body fat content and BMI did not change over the time of intervention for RA and OL. At the end of the study a significant reduction in hepatic fat content (P=0.038) could be observed for RA (13.09±1.61 before vs. 11.14±1.58% after intervention) vs. OL (13.29±2.52 before vs. 15.73±2.74% after intervention). For RA, a 21% reduction (P<0.02) in serum free fatty acids was observed after eight weeks of oil consumption whereas no significant changes were seen for OL. Consuming RA resulted in a slight reduction in basal endogenous glucose production (1.71±0.15 before vs. 1.49±0.mg/kg/min after intervention, P=n.s.) compared to OL (1.66±0.before vs. 1.65±0.mg/kg/min after intervention, P=n.s.). There were no significant changes in total body insulin sensitivity and serum cholesterol levels in RA or OL. Our results demonstrate a beneficial effect of the fatty acid composition of RA on hepatic lipid production as shown by reduced hepatic fat content and free fatty acid levels. Disclosure M. Kruse: None. M. Kemper: None. S. Gancheva: None. D. Dannenberger: None. D.F. Markgraf: None. M. Roden: Speaker's Bureau; Self; Boehringer Ingelheim GmbH. Research Support; Self; Boehringer Ingelheim GmbH. Consultant; Self; Poxel SA. Research Support; Self; Danone Nutricia Early Life Nutrition, GlaxoSmithKline plc., Nutricia Advanced Medical Nutrition, Sanofi. A.F. Pfeiffer: None.