Olive-oil-enriched diet: effect on serum lipoprotein levels 960 Am J C/in Nuir l988;47:960-4. Printed in USA. © 1988 American Society for Ginical Nutrition and biliary cholesterol saturation13 Giovannella Baggio, MD; Antonio Pagnan, MD; Maurizio Muraca, MD; Scipione Martini, MD; A/do Opportuno, MD; Andrea Bonanome, MD; Giovan Battista Ambrosio, MD; Silvana Ferrari, MD; Patrizia Guarini, PhD; Diana Piccolo, MD; Enzo Manzato, MD; Roberto Corrocher, MD; and Gaetano Crepaldi, MD ABSTRACT The effect of diet enriched with a monounsaturated fatty acid (olive oil) on serum lipoproteins, biliary cholesterol saturation index, and gallbladder mility compared with a standard low-fat diet was evaluated in 1 1 young volunteers admitteo to a metabolic ward. A significant decrease of mean total cholesterol (-9.5%), total apo B (-7.4%), LDL cholesterol (-12.2%), and total triglycerides (-25.5%) was observed after the olive-oil- enriched diet. Total HDL- and HDL-subfractions-cholesterol levels as well as serum apo A-I mean levels remained unchanged. Cholesterol saturation index of the bile and fasting and after-meal gallbladder volumes were unaffected by the enriched diet as compared with the low- fat diet. Olive oil may be a natural fat that can be used for the control of plasma and LDL cholesterol as a valid alternative to polyunsaturated fatty acids. Am J Clin Nutr 1988; 47:960-4. KEY WORDS Olive oil, monounsaturated fatty acids, polyunsaturated fatty acids, lipo- protein, apolipoprotein, biliary lipids, gallbladder motility Introduction High plasma cholesterol levels, mainly low-density-li- poprotein (LDL) cholesterol, are a widely recognized major risk factor for coronary heart disease (CHD) whereas high levels of high-density lipoprotein (HDL) are considered a negative risk factor for CHD (1-3). Different dietary approaches have been recommended to modify plasma lipoprotein levels and to decrease CHD incidence (4-8). Epidemiological surveys showed low cholesterol levels and low prevalence ofCHD in populations consuming a diet low in total fat, saturated fatty acids (FAs) and cho- lesterol (9); intervention studies showed a clear hypo- cholesterolemic effect of such diets (iO-i4). Diets rich in polyunsaturated FAs seem to lower HDL and HDL- subfraction levels (i 1, 14) and to increase the risk for some noncardiovascular diseases (1 3, 1 5, 16). In Mediterranean countries, in spite of high-average fat intake (40% oftotal calories), CHD rates and plasma cholesterol levels are relatively low (1 , 5, 9). In these countries the usual diet is high in olive oil, which is rich in monounsaturated FAs (oleic acid). For the same total cholesterol levels, death rate for CHD is lower in Mediterranean than in other countries, such as Finland and the United States (1), suggesting that the influence ofdiet may not be simply related to plasma and LDL-cholesterol levels but also to different athero- sclerosis risk factors (5). In the last few years investigators have examined the influence ofdiets high in oleic acid on lipid and lipopro- tein levels in comparison with other types offat (17-20); they have shown a hypocholesterolemic effect similar to that of conventional hypolipidemic diets with no effect on HDL levels (17, 19, 20). In these studies oleic acid, obtained by an artificial enrichment ofsaffiower oil, was administered in liquid-formula diet. Controlled clinical trials on the effects ofolive oil as a natural source of oleic acid on lipid metabolism have been scanty (2i, 22). The aim of this study was to evaluate the effects on serum lipids and lipoproteins of an olive-oil-enriched diet in comparison with a low-fat diet. We also investi- gated the effect ofthese diets on biliary lipid composition I From the Institute oflnternal Medicine and the Ginica Medica I, University ofPadua; the Military Hospital ofPadua; and the Institute ofChemical and Clinical Microscopy and the Patologia Medica, Uni- versity ofVerona, Italy. 2 Supported in part by The European Economical Committee (EEC). 3 Address reprints requests to Giovannella Baggio, MD, Institute of Internal Medicine, University of Padua, 2 Via Giustiniani, 35128 Pa- dova, Italy. ReceivedMarch23, 1987. Accepted for publication August 4, 1987. by guest on July 10, 2011 www.ajcn.org Downloaded from