WASHINGTON - A Mediterranean diet, even drenched in olive oil and studded with nuts, beats a low-fat diet hands-down in preventing strokes and heart attacks in healthy older people at high risk of cardiovascular disease, according to research released Monday.
The latest smack-down in the diet wars appears to deal a knock-out blow to the notion that high-fat olive oil and tree nuts - walnuts, almonds and hazelnuts - are a no-no for those wishing to improve their health.
On the contrary, Spanish researchers concluded that the consumption of extra-virgin olive oil and nuts "were probably responsible for most of the observed benefits" attained by those in the two study groups on a Mediterranean diet.
The findings, released by the New England Journal of Medicine, also add to mounting evidence contradicting a long-held tenet of dieting to improve health: that all calories are equal.
A Mediterranean diet is rich in fatty fish, fruits, vegetables and fatty acids, and almost entirely without red meat.
Although many studies have suggested its benefits, the current trial is the first to meet the "gold standard" of biomedical research, with large numbers of people randomly assigned to distinct groups and followed for several years.
The superiority of the Mediterranean diet was substantial: Compared with a group of 2,450 people who were urged to follow a low-fat diet, the 4,997 on a Mediterranean diet supplemented either with nuts (2,454 people) or extra-virgin olive oil (2,543 people) were 30 percent less likely to suffer either a heart attack, stroke or death attributed to cardiovascular disease.
Mediterranean dieters were almost 40 percent less likely than low-fat dieters to have a stroke during the follow-up period, which lasted nearly five years. The superiority of the Mediterranean diet was consistent across virtually all subgroups. Only among a small group of people without hypertension did a low-fat diet show better results.
Male participants ranged in age from 55 to 80, women from 60 to 80. All of them either had Type 2 diabetes or satisfied at least three of the following criteria: They were active smokers, were overweight or obese, had a family history of premature heart disease or had hypertension or worrisome cholesterol readings.
The findings "blow the low-fat diet myth out of the water," said Cleveland Clinic cardiologist Steven Nissen, who was not involved in the research.
Nissen, an expert on the effects of drugs and nutrition on cardiovascular risk, called the study "spectacular" and touted the findings as impressive.