PREDIMED: Supplemented Mediterranean Diets and the Prevention of Cardiovascular Events

Published - Written by John Staples

Mr. Smith decided to get serious about his cardiovascular health when he turned sixty. He comes to your clinic one day to tell you that he’s stopped smoking and that he’s been more attentive to the treatment of his hypertension and dyslipidemia over the last few months.

“I’m really turning things around, Doc,” he tells you, “but I need to know how to improve my diet. I know the basics – eat more vegetables and whole grains, cut back on trans- and saturated fats, avoid salt. You got any other words of wisdom on what else works?”

While composing your answer, you may want to consider the results of the PREDIMED study, an exciting multicenter primary prevention trial published in this week’s NEJM. In this trial, Dr. Ramon Estruch (Hospital Clinic, Barcelona, Spain), Dr. Miguel Angel Martínez-González (Clínica Universidad de Navarra, Pamplona, Spain) and colleagues randomized 7447 patients at high risk for cardiovascular disease to one of three arms: One group was advised to follow a Mediterranean diet supplemented with extra-virgin olive oil, a second group was advised to follow a Mediterranean diet supplemented with mixed nuts, and the controls were advised to decrease dietary fat intake. None of the patients were told to limit their total caloric intake. Patients received yearly personalized dietary advice and free olive oil, nuts, or non-food gifts (depending on their treatment assignment). They were then followed for the development of hard cardiovascular endpoints.

After a median of 4.8 years, patients following either of the supplemented Mediterranean diets were significantly less likely than the control patients to suffer from the combined endpoint of myocardial infarction, stroke or cardiovascular death. The absolute risk of developing one of these events was reduced by about 3 events per 1000 person-years, corresponding to a relative risk reduction of about 30%. Should patients and physicians be going mad for Mediterranean, nuts for nuts, and ga-ga for EVOO?

“The PREDIMED trial shows some pretty impressive numbers,” says Cardiologist and NEJM Deputy Editor Dr. John Jarcho, “But it also has its limitations.” He cites the amendment of the control arm protocol mid-trial (to allow these patients to receive the same amount of clinical support received by patients in the other arms) and the disproportionate loss to follow-up in the control arm as reasons for caution.

As for Mr. Smith? A visit to a dietician might help to convert his nutritional knowledge into practical suggestions. He might also appreciate hearing a little about the PREDIMED trial – and the broader implication that diet can make a difference.

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Hungry for more? In the same issue of NEJM, you’ll also find an editorial discussing the PREDIMED trial and a Perspective on the modern history of the relationship between the Mediterranean diet and cardiovascular health.