title: Diabetes and the Mediterranean diet: a beneficial effect of oleic acid on insulin sensitivity, adipocyte glucose transport and endothelium-dependent vasoreactivity.
abstract: Abnormalities in endothelial function may be associated with increased cardiovascular risk in diabetic patients. We examined the effect of an oleic-acid-rich diet on insulin resistance and endothelium-dependent vasoreactivity in type 2 diabetes. Eleven type 2 diabetic patients were changed from their usual linoleic-acid-rich diet and treated for 2 months with an oleic-acid-rich diet. Insulin-mediated glucose transport was measured in isolated adipocytes. Fatty acid composition of the adipocyte membranes was determined by gas-liquid chromatography and flow-mediated endothelium-dependent and -independent vasodilatation were measured in the superficial femoral artery at the end of each dietary period. There was a significant increase in oleic acid and a decrease in linoleic acid on the oleic-acid-rich diet (p<0.0001). Diabetic control was not different between the diets, but there was a small but significant decrease in fasting glucose/insulin on the oleic-acid-rich diet. Insulin-stimulated (1 ng/ml) glucose transport was significantly greater on the oleic- acid-rich diet (0.56+/-0.17 vs. 0.29+/-0.14 nmol/10(5) cells/3 min, p<0.0001). Endothelium-dependent flow-mediated vasodilatation (FMD) was significantly greater on the oleic-acid-rich diet (3.90+/-0.97% vs. 6.12+/-1.36% p<0.0001). There was a significant correlation between adipocyte membrane oleic/linoleic acid and insulin-mediated glucose transport (p<0.001) but no relationship between insulin-stimulated glucose transport and change in endothelium-dependent FMD. There was a significant positive correlation between adipocyte membrane oleic/linoleic acid and endothelium-dependent FMD (r=0.61, p<0.001). Change from polyunsaturated to monounsaturated diet in type 2 diabetes reduced insulin resistance and restored endothelium-dependent vasodilatation, suggesting an explanation for the anti-atherogenic benefits of a Mediterranean-type diet.
authors.affiliation: Departments of Endocrinology and Diabetes, Trinity College, Dublin, Ireland.
authors.forename: M
authors.initials: M
authors.lastname: Ryan
authors.forename: D
authors.initials: D
authors.lastname: McInerney
authors.forename: D
authors.initials: D
authors.lastname: Owens
authors.forename: P
authors.initials: P
authors.lastname: Collins
authors.forename: A
authors.initials: A
authors.lastname: Johnson
authors.forename: G H
authors.initials: GH
authors.lastname: Tomkin
mesh_terms: D017667:Adipocytes / Q000378:metabolism; D000328:Adult; D000368:Aged; D001692:Biological Transport / Q000502:physiology; D003924:Diabetes Mellitus, Type 2 / Q000178:diet therapy* / Q000378:metabolism; D004032:Diet; D004730:Endothelium, Vascular / Q000502:physiology; D005227:Fatty Acids / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000502:physiology; D008297:Male; D008563:Membrane Lipids / Q000737:chemistry; D008875:Middle Aged; D019301:Oleic Acid / Q000502:physiology; D014664:Vasodilation / Q000502:physiology
chemical_list: D005227:Fatty Acids; D007328:Insulin; D008563:Membrane Lipids; D019301:Oleic Acid; D005947:Glucose