A Mediterranean diet supplemented with extra-virgin olive oil or nuts may be associated with a lower risk of cardiovascular events compared to a reduced-fat diet, according to the results of the PREDIMED trial published June 13 in the New England Journal of Medicine (NEJM).

In a multicenter trial in Spain, Ramón Estruch, MD, PhD, et al., assigned 7,447 participants who were at high cardiovascular risk but with no cardiovascular disease at enrollment to one of three diets: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with mixed nuts or a control diet that reduced dietary fat. After a median follow-up of 4.8 years, the authors sought to assess the primary endpoint of major cardiovascular events such as myocardial infarction, stroke or death from cardiovascular causes.

Results showed that cardiovascular events occurred in 288 participants: 96 events in the group assigned to a Mediterranean diet supplemented with extra-virgin olive oil (3.8 percent), 83 events in the group assigned to a Mediterranean diet supplemented with mixed nuts (3.4 percent) and 109 events in the control group (4.4 percent). Adjusting for baseline characteristics and propensity scores in all the participants, the hazard ratio was 0.69 (95 percent confidence interval [CI], 0.53 – 0.91) for a Mediterranean diet with extra-virgin olive oil and 0.72 (95 percent CI, 0.54 – 0.95) for a Mediterranean diet with nuts, as compared with the control diet.

The authors note that their analysis, which incorporated information about adherence to the diets, suggests that the difference in rate of cardiovascular events between those assigned to the Mediterranean diets and those assigned the control diet was greater among participants with better adherence. The authors add that they had previously reported results for the primary end point in NEJM in 2013 but “have withdrawn our previously published report and now report revised effect estimates based on analyses that do not rely exclusively on the assumption that all the participants were randomly assigned.”

“In [previous] observational cohort studies and a secondary prevention trial, increasing adherence to the Mediterranean diet has been consistently associated with lower cardiovascular risk,” the authors conclude. “Our findings support a beneficial effect of the Mediterranean diet for the primary prevention of cardiovascular disease.”

Keywords: Diet, Mediterranean, Nuts, Dietary Fats, Secondary Prevention, Cardiovascular Diseases, Follow-Up Studies, Risk Factors, Diet, Fat-Restricted, Primary Prevention, Dietary Supplements, Myocardial Infarction, Stroke

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