Review
Copyright ©2009 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Apr 21, 2009; 15(15): 1809-1815
Published online Apr 21, 2009. doi: 10.3748/wjg.15.1809
Olive oil consumption and non-alcoholic fatty liver disease
Nimer Assy, Faris Nassar, Gattas Nasser, Maria Grosovski
Nimer Assy, Liver Unit, Ziv Medical Center, Safed, Israel; Faculty of Medicine, Technion Institute, Haifa 32000, Israel
Faris Nassar, Gattas Nasser, Department of Medicine, Western Galilee Hospital, Nahariya 22356, Israel
Maria Grosovski, Department of Biotechnology, Ort-Braude College, Karmiel 20100, Israel
Author contributions: Assy N wrote the paper; Nasser G and Nassar F helped in collecting data; Grosovski M analyzed the data.
Correspondence to: Dr. Nimer Assy, Liver Unit, Ziv Medical Centre, Safed 13100, Israel. assy.n@ziv.health.gov.il
Telephone: +97-246828441/5
Fax: +97-246828442
Received: September 12, 2008
Revised: March 2, 2009
Accepted: March 9, 2009
Published online: April 21, 2009
Abstract

The clinical implications of non-alcoholic fatty liver diseases (NAFLD) derive from their potential to progress to fibrosis and cirrhosis. Inappropriate dietary fat intake, excessive intake of soft drinks, insulin resistance and increased oxidative stress results in increased free fatty acid delivery to the liver and increased hepatic triglyceride (TG) accumulation. An olive oil-rich diet decreases accumulation of TGs in the liver, improves postprandial TGs, glucose and glucagon-like peptide-1 responses in insulin-resistant subjects, and upregulates glucose transporter-2 expression in the liver. The principal mechanisms include: decreased nuclear factor-kappaB activation, decreased low-density lipoprotein oxidation, and improved insulin resistance by reduced production of inflammatory cytokines (tumor necrosis factor, interleukin-6) and improvement of jun N-terminal kinase-mediated phosphorylation of insulin receptor substrate-1. The beneficial effect of the Mediterranean diet is derived from monounsaturated fatty acids, mainly from olive oil. In this review, we describe the dietary sources of the monounsaturated fatty acids, the composition of olive oil, dietary fats and their relationship to insulin resistance and postprandial lipid and glucose responses in non-alcoholic steatohepatitis, clinical and experimental studies that assess the relationship between olive oil and NAFLD, and the mechanism by which olive oil ameliorates fatty liver, and we discuss future perspectives.

Keywords: Liver steatosis; Fatty liver; Olive oil; Fatty acids; Monounsaturated; Non-alcoholic steatohepatitis; Lipids; Oleic acid; Non-alcoholic fatty liver disease