Effects of a Mediterranean-Style Diet on Cardiovascular Risk Factors: A Randomized Trial

Study Questions:

Does a Mediterranean diet improve risk factors for cardiovascular disease?


Data from a substudy of the PREDIMED (Prevención con Dieta Mediterránea) trial were used for this analysis. PREDIMED is a multicenter, randomized, primary prevention trial of cardiovascular disease, which enrolled asymptomatic patients (ages 55-80 years from primary care centers in 10 teaching hospitals in Spain). All participants were high risk for cardiovascular disease. Participants were assigned to a low-fat diet (n = 257) or to one of two Mediterranean diets. Those allocated to Mediterranean diets received nutritional education and either free virgin olive oil, 1 L/wk (n = 257), or free nuts, 30 g/d (n = 258). Primary outcomes of interest for the substudy included body weight, blood pressure, lipid profile, glucose levels, and inflammatory molecules, all of which were evaluated at 3 months.


A total of 772 adults were enrolled; the completion rate was 99.6%. Compared with the low-fat diet, the two 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% confidence interval [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.


The investigators concluded that compared with a low-fat diet, Mediterranean diets supplemented with olive oil or nuts have beneficial effects on cardiovascular risk factors.


Although this paper is limited to intermediate outcomes, these findings complement PREDIMED’s results, which demonstrate reductions in cardiovascular events.

Clinical Topics: Diabetes and Cardiometabolic Disease, Dyslipidemia, Prevention, Lipid Metabolism, Nonstatins, Diet

Keywords: Body Weight, Blood Pressure, Risk Factors, Primary Prevention, Glucose, Complement System Proteins, Cholesterol, C-Reactive Protein, Dietary Supplements, Plant Oils, Spain, Cardiovascular Diseases, Diet, Fat-Restricted, Primary Health Care

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