Tuesday, February 26, 2013

Mediterranean Diet Slashes Heart Disease Risk

Consuming a Mediterranean diet supplemented with either extra virgin olive oil or mixed nuts may reduce the risk of cardiovascular events by 30% and reduce the risk of stroke by 49% when compared to a reference diet consisting of advice on a low-fat diet, according to a new study published in the New England Journal of Medicine.

As one of the world's largest and longest dietary intervention studies, PREDIMED is a multicenter, randomized, primary prevention trial of cardiovascular disease funded by the Spanish Ministry of Health. The study was led by researchers at the Hospital Clinic in Barcelona and Clinical Universidad de Navaraa in Pamplona, Spain.

"These results support the benefits of the Mediterranean diet for CV risk reduction [and] are particularly relevant given the challenges of achieving and maintaining weight loss," the researchers said.

The trial included 7,447 individuals aged 55 to 80 years, none of whom had established cardiovascular disease but who were at high cardiovascular risk. Participants were randomized to one of two Mediterranean diet groups (one supplemented with olive oil, the other with nuts) or to a control diet wherein subjects were advised to try to reduce dietary fat.

Patients in the Mediterranean-diet groups were invited to regular dietary training sessions; by contrast, those in the control group were, for the first three years, sent leaflets explaining a low-fat diet. After a protocol amendment at the 3-year mark, patients following low-fat diets also were invited to regular group sessions and offered personalized advice at the same level of intensity as the Mediterranean groups.

The study was stopped when an interim analysis at 4.8 years revealed a clear signal of benefit among subjects eating the Mediterranean diets. In the olive-oil and mixed-nut Mediterranean diet groups, the primary end point (MI, stroke or CV death) was reduced by 30% and 28% respectively, as compared with the control group.

Study dropouts, meanwhile, were twice as common in the control diet group as in the Mediterranean diet group (11.3% vs 4.9%). "Favorable trends" were seen for both stroke and MI rates among subjects eating the Mediterranean diet, but numbers were too low to be relevant statistically. A total of 288 subjects experienced an event in the study: 96 events in the olive-oil group, 83 in the nut group, and 109 in the control group.
Subjects randomized to the Mediterranean diets were not told to reduce calories, a major barrier to success in many dietary interventions, particularly the long-supported "low-fat" approach.

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