Abstract P404: “Mediterranean” Dietary Pattern for the Primary Prevention of Cardiovascular Disease: A Cochrane Systematic Review
Background: Observational studies have confirmed benefits of adherence to a Mediterranean dietary pattern on CVD risk factors. Clinical trial evidence is limited, mostly in secondary prevention.
Objective: To determine the effectiveness of dietary advice to follow a Mediterranean style diet or the provision of foods relevant to the Mediterranean diet for the primary prevention of CVD.
Methods: The following electronic databases were searched with no language restrictions from their inception to October 2011: MEDLINE, EMBASE, Web of Science, the Cochrane Library and trial registers. Studies were included if they fulfilled the following criteria: study design - randomized controlled trials (RCTs), participants - free of CVD (includes those at high risk), intervention - advice to follow a Mediterranean dietary pattern or provision of foods relevant to the Mediterranean diet. At least 2 of the following components were required to meet our inclusion criteria: (1) high monounsaturated/saturated fat ratio (use of olive oil as main cooking ingredient) (2) low to moderate red wine consumption (3) high consumption of legumes (4) high consumption of grains and cereals (5) high consumption of fruits and vegetables (6) low consumption of meat and meat products and increased consumption of fish (7) moderate consumption of milk and dairy products, comparator - no intervention or minimal intervention, outcomes - diagnosis of CVD or change in the risk factor profile for CVD (blood pressure, lipids).
Results: Database searching resulted in 8535 hits of which 183 went forward for formal inclusion/exclusion, 6 RCTs met the inclusion criteria. Included trials were heterogeneous in the participants recruited, the intervention, outcomes reported and follow-up periods. In all trials the intervention was dietary advice. Only one trial, the largest with 19,541 postmenopausal women randomised reported clinical events and showed no effect of a Mediterranean style dietary pattern on fatal and non fatal endpoints at 8 years follow up (WHI). Cardiovascular risk factors were measured in all trials but heterogeneity between trials precluded meta-analysis for most outcomes with the exception of LDL cholesterol where 3 trials contributed to the analysis. There was a small reduction in LDL cholesterol with the dietary intervention (mean difference -0.07 mmol/L, 95% CI -0.13, -0.01), with results dominated by the WHI trial. Individual trials showed some favourable effects on reducing total cholesterol and blood pressure.
Conclusions: There are currently very few RCTs that met our inclusion criteria to examine the effectiveness of the Mediterranean dietary pattern for the primary prevention of CVD. The limited evidence suggests some favourable effects on cardiovascular risk factors but more trials are needed to confirm this.
- © 2013 by American Heart Association, Inc.