Mediterranean-Style Diet for the Primary and Secondary Prevention of Cardiovascular Disease

Summary

A Cochrane review [Abstract] 1 included 30 studies with a total of 12 461 subjects. Definitions of the Mediterranean diet differed but all comprised at least the 2 core components of a high monounsaturated/saturated fat ratio (use of olive oil as main cooking ingredient and/or consumption of other traditional foods high in monounsaturated fats such as tree nuts) and high intake of plant-based foods, including fruits, vegetables and legumes.

Primary prevention:One study (n=7 447) showed that advice to follow a Mediterranean diet plus supplemental extra-virgin olive oil or tree nuts compared to a low-fat diet reduced composite clinical events (cardiovascular disease (CVD) and total mortality, myocardial infarction (MI) and stroke; HR 0.70, 95% CI 0.58 to 0.85) and the number of strokes (HR 0.60, 95% CI 0.45 to 0.80; a decrease from 24/1000 to 14/1000, 95% CI 11 to 19), but did not have effect on CVD mortality (HR 0.81, 95% CI 0.50 to 1.32) or total mortality (HR 1.0, 95% CI 0.81 to 1.24) over 4.8 years. There was a possible small reduction in total cholesterol (-0.16 mmol/L, 95% CI -0.32 to 0.00; 5 studies, n=569) and a reduction in systolic (-2.99 mmHg, 95% CI -3.45 to -2.53; 2 studies, n=269) and diastolic blood pressure (-2.0 mmHg, 95% CI -2.29 to -1.71; 2 studies, n=269), with little or no effect on LDL or HDL cholesterol or triglycerides when Mediterranean dietary intervention was compared to no intervention or minimal intervention. Mediterranean dietary intervention compared to another dietary intervention produced a small reduction in LDL cholesterol (-0.15 mmol/L, 95% CI -0.27 to -0.02; 7 studies, n=947) and triglycerides (-0.09 mmol/L, 95% CI -0.16 to -0.01; 7 studies, n=939) with little or no effect on total or HDL cholesterol or blood pressure.

Secondary prevention: Advice to follow a Mediterranean diet and supplemental canola margarine (605 patients within 6 months of a MI) reduced adjusted estimates for a composite endpoint of CVD deaths and non-fatal MI (HR 0.28, 95% CI 0.15 to 0.52), CVD mortality (HR 0.35, 95% CI 0.15 to 0.82) and total mortality (HR 0.44, 95% CI 0.21 to 0.92) over 46 months compared to usual care. There was little or no effect of a Mediterranean-style diet on lipid levels and blood pressure.