Effects of a Mediterranean-Style Diet on Cardiovascular Risk Factors

A Randomized Trial

4 July 2006 | Volume 145 Issue 1 | Pages 1-11

Background: The Mediterranean diet has been shown to have beneficial effects on cardiovascular risk factors.

Objective: To compare the short-term effects of 2 Mediterranean diets versus those of a low-fat diet on intermediate markers of cardiovascular risk.

Design: Substudy of a multicenter, randomized, primary prevention trial of cardiovascular disease (Prevención con Dieta Mediterránea [PREDIMED] Study).

Setting: Primary care centers affiliated with 10 teaching hospitals.

Participants: 772 asymptomatic persons 55 to 80 years of age at high cardiovascular risk who were recruited from October 2003 to March 2004.

Interventions: Participants were assigned to a low-fat diet (n = 257) or to 1 of 2 Mediterranean diets. Those allocated to Mediterranean diets received nutritional education and either free virgin olive oil, 1 liter per week (n = 257), or free nuts, 30 g/d (n = 258). The authors evaluated outcome changes at 3 months.

Measurements: Body weight, blood pressure, lipid profile, glucose levels, and inflammatory molecules.

Results: The completion rate was 99.6%. Compared with the low-fat diet, the 2 Mediterranean diets produced beneficial changes in most outcomes. Compared with the low-fat diet, the mean changes in the Mediterranean diet with olive oil group and the Mediterranean diet with nuts group were –0.39 mmol/L (95% CI, –0.70 to – 0.07 mmol/L) and – 0.30 mmol/L (CI, –0.58 to – 0.01 mmol/L), respectively, for plasma glucose levels; –5.9 mm Hg (CI, –8.7 to –3.1 mm Hg) and – 7.1 mm Hg (CI, –10.0 to –4.1 mm Hg), respectively, for systolic blood pressure; and –0.38 (CI, –0.55 to – 0.22) and – 0.26 (CI, –0.42 to –0.10), respectively, for the cholesterol–high-density lipoprotein cholesterol ratio. The Mediterranean diet with olive oil reduced C-reactive protein levels by 0.54 mg/L (CI, 1.04 to 0.03 mg/L) compared with the low-fat diet.

Limitations: This short-term study did not focus on clinical outcomes. Nutritional education about low-fat diet was less intense than education about Mediterranean diets.

Conclusion: Compared with a low-fat diet, Mediterranean diets supplemented with olive oil or nuts have beneficial effects on cardiovascular risk factors.

*For a list of additional PREDIMED Study Investigators, see the Appendix.

Editors' Notes Context Some experts attribute a low incidence of heart disease in Mediterranean countries to dietary habits. Contribution In this multicenter, 3-group trial, investigators randomly assigned 772 adults at high risk for cardiovascular disease to a low-fat diet or to a Mediterranean diet supplemented with either virgin olive oil (1 L per week) or nuts (30 g per day). After 3 months, the Mediterranean diet groups had lower mean plasma glucose level, systolic blood pressure, and total cholesterol–high-density lipoprotein cholesterol ratio than the low-fat diet group. Cautions The Mediterranean diet groups received more nutritional education than the low-fat diet group. Implications Mediterranean diets supplemented with olive oil or nuts may improve cardiovascular risk factors. —The Editors

 

Author and Article Information

From Institut d'Investigacions Biomèdiques August Pi Sunyer (IDIBAPS), Municipal Institut for Medical Research (IMIM), University of Barcelona, and Catalan Institute of Health, Barcelona, Spain; University of Navarra–Clínica Universitaria de Navarra, Pamplona, Spain; University of Valencia, Valencia, Spain; University Rovira i Virgili, Reus (Tarragona), Spain; Instituto de la Grasa, Consejo Superior de Investigaciones Cientificas, Hospitales Universitarios Vírgen del Rocío, and San Pablo Health Center, Sevilla, Spain; Hospital Son Dureta, Palma de Mallorca, Spain; University of Malaga, Malaga, Spain; Hospital Txangorritxu, Vitoria, Spain; and Hospital Carlos III, Madrid, Spain.

International Standard Randomized Controlled Trial Number (ISRCTN): 35739639.

Acknowledgments: The authors thank the Fundación Patrimonio Comunal Olivarero and Hojiblanca SA, California Walnut Commission, Borges SA, and Morella Nuts SA for donating the olive oil, walnuts, almonds, and hazelnuts, respectively, used in the study. They also thank the participants for their enthusiastic collaboration, the PREDIMED personnel for excellent assistance with all aspects of the trial, and Emili Corbella for providing expert assistance with statistical analyses.

Grant Support: By the Spanish Ministry of Health (Fondo de Investigación Sanitaria, Red G03/140).

Potential Financial Conflicts of Interest: Consultancies: E. Ros (California Walnut Commission); Honoraria: E. Ros (California Walnut Commission); Grants received: E. Ros (California Walnut Commission); Grants pending: E. Ros (California Walnut Commission).

Requests for Single Reprints: Ramon Estruch, MD, PhD, Department of Internal Medicine, Hospital Clinic, Villarroel 170, 08036 Barcelona, Spain; e-mail, restruch{at}clinic.ub.es.

Current Author Addresses: Dr. Estruch: Department of Internal Medicine, Hospital Clinic, Villarroel 170, 08036 Barcelona, Spain.

Dr. Martínez-González: Department of Preventive Medicine and Public Health, School of Medicine–Clínica Universitaria de Navarra, University of Navarra, Irunlarrea 1, 31080 Pamplona, Navarra, Spain.

Dr. Corella: Department of Preventive Medicine, School of Medicine, University of Valencia, Avda. Blasco Ibáñez 15, 46010 Valencia, Spain.

Dr. Salas-Salvadó: Human Nutrition Department, School of Medicine, University Rovira i Virgili, San Llorenç 21, 43201 Reus (Tarragona), Spain.

Dr. Ruiz-Gutiérrez: Instituto de la Grasa, Consejo Superior de Investigaciones Cientificas, Avda. Padre García Tejero 4, 41012 Sevilla, Spain.

Dr. Covas: Cardiovascular Epidemiology Unit, Municipal Institut for Medical Research (IMIM), Barcelona, Dr. Aiguader 80, 08003 Barcelona, Spain.

Dr. Fiol: Department of Cardiology, Hospital Universitario Son Dureta, Andrea Doria 55, 07014 Palma de Mallorca, Spain.

Dr. Gómez-Gracia: Department of Epidemiology, School of Medicine, University of Malaga, Capus de Teatinos s/n, 29071 Málaga, Spain.

Dr. López-Sabater: Department of Nutrition and Bromatology, School of Pharmacy, Avda. Joan XXIII s/n, Barcelona, Spain.

Dr. Vinyoles: Primary Care Division, Catalan Institute of Health, Gran Via 587, 08007 Barcelona, Spain.

Dr. Arós: Department of Cardiology, Hospital Txangorritxu, José Achotegui s/n, 01009 Vitoria, Alava, Spain.

Dr. Conde: Department of Epidemiology and Public Health, Hospitales Universitarios Vírgen del Rocío, Manuel Siurot s/n, 41013 Sevilla, Spain.

Dr. Lahoz: Arteriosclerosis Unit, Hospital Carlos III, Sinesio Delgado 10, 28029 Madrid, Spain.

Dr. Lapetra: San Pablo Health Center, Damasco s/n, 41007 Sevilla, Spain.

Dr. Sáez: Department of Biochemistry, School of Medicine, University of Valencia, Avda. Blasco Ibáñez 15, 46010 Valencia, Spain.

Dr. Ros: Lipid Clinic, Endocrinology and Nutrition Service, Hospital Clinic, Villarroel 170, 08036 Barcelona, Spain.

Author Contributions: Conception and design: R. Estruch, M.. Martínez-González, D. Corella, J. Salas-Salvadó, V. Ruiz-Gutiérrez, M.I. Covas, M. Fiol, E. Gómez-Gracia, M. Conde, C. Lahoz, J. Lapetra, G. Sáez, E. Ros.

Analysis and interpretation of the data: R. Estruch, M.. Martínez-González, D. Corella, J. Salas-Salvadó, V. Ruiz-Gutiérrez, M.I. Covas, E. Gómez-Gracia, M.C. López-Sabater, J. Lapetra, G. Sáez, E. Ros.

Drafting of the article: R. Estruch, M.. Martínez-González, D. Corella, J. Salas-Salvadó, V. Ruiz-Gutiérrez, M.I. Covas, F. Arós, C. Lahoz, G. Sáez, E. Ros.

Critical revision of the article for important intellectual content: R. Estruch, M.. Martínez-González, D. Corella, J. Salas-Salvadó, V. Ruiz-Gutiérrez, M.I. Covas, M. Fiol, E. Gómez-Gracia, M.C. López-Sabater, M. Conde, J. Lapetra, G. Sáez, E. Ros.

Final approval of the article: R. Estruch, M.. Martínez-González, D. Corella, J. Salas-Salvadó, V. Ruiz-Gutiérrez, M.I. Covas, M. Fiol, E. Gómez-Gracia, E. Vinyoles, M. Conde, J. Lapetra, G. Sáez, E. Ros.

Provision of study materials or patients: R. Estruch, M.. Martínez-González, D. Corella, J. Salas-Salvadó, V. Ruiz-Gutiérrez, M.I. Covas, M. Fiol, E. Gómez-Gracia, E. Vinyoles, M. Conde, C. Lahoz, J. Lapetra, G. Sáez, E. Ros.

Statistical expertise: R. Estruch, M.. Martínez-González, D. Corella, J. Salas-Salvadó, M.I. Covas, G. Sáez, E. Ros.

Obtaining of funding: R. Estruch, M.. Martínez-González, D. Corella, J. Salas-Salvadó, V. Ruiz-Gutiérrez, M.I. Covas, M. Fiol, E. Gómez-Gracia, M. Conde, J. Lapetra, G. Sáez, E. Ros.

Administrative, technical, or logistic support: R. Estruch, M.. Martínez-González, D. Corella, J. Salas-Salvadó, V. Ruiz-Gutiérrez, M.I. Covas, E. Gómez-Gracia, E. Vinyoles, F. Arós, M. Conde, J. Lapetra, G. Sáez, E. Ros.

Collection and assembly of data: R. Estruch, M.. Martínez-González, D. Corella, J. Salas-Salvadó, M.I. Covas, E. Gómez-Gracia, F. Arós, J. Lapetra, G. Sáez, E. Ros.

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