Mediterranean diet can cut heart disease, study finds
Updated 11:15 pm, Monday, February 25, 2013
About 30 percent of heart attacks, strokes and deaths from heart disease can be prevented in people at high risk if they switch to a Mediterranean diet rich in olive oil, nuts, beans, fish, fruits and vegetables, and even drink wine with meals, a large and rigorous new study found.
The findings, published on the New England Journal of Medicine's website Monday, were based on the first major clinical trial to measure the diet's effect on heart risks. The magnitude of the diet's benefits startled experts. The study ended early, after almost five years, because the results were so clear it was considered unethical to continue.
The diet helped those following it even though they did not lose weight and most of them were already taking statins, or blood pressure or diabetes drugs to lower their heart disease risk.
“Really impressive,” said Rachel Johnson, a professor of nutrition at the University of Vermont and a spokeswoman for the American Heart Association. “And the really important thing, the coolest thing, is that they used very meaningful end points. They did not look at risk factors like cholesterol or hypertension or weight. They looked at heart attacks and strokes and death. At the end of the day, that is what really matters.”
Heart disease experts said the study was a triumph because it showed a diet is powerful in reducing heart disease risk, and it used the most rigorous methods. Scientists randomly assigned 7,447 people in Spain who were overweight, were smokers, had diabetes or other risk factors for heart disease to follow the Mediterranean diet or a low-fat one.
Low-fat diets have not been shown in any rigorous way to be helpful, and they are also very hard for patients to maintain — a reality born out in the new study, said Dr. Steven Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic Foundation.
“Now along comes this group and does a gigantic study in Spain that says you can eat a nicely balanced diet with fruits and vegetables and olive oil and lower heart disease by 30 percent,” he said. “And you can actually enjoy life.”
The researchers randomly assigned subjects at high risk of heart disease to three groups.
One would be given a low-fat diet and the two other groups followed a Mediterranean diet. One group assigned to that diet was instructed to use at least four tablespoons of extra virgin olive oil a day. The other group got a combination of walnuts, almonds and hazelnuts and was instructed to eat about an ounce of them each day. The mainstays of the Mediterranean diet consisted of at least three servings a day of fruits and at least two of vegetables. Participants were to eat fish at least three times a week and legumes, which include beans, peas and lentils, at least three times a week. They were to eat white meat instead of red, and, for those accustomed to drinking, to have at least seven glasses of wine a week with meals.
They were encouraged to avoid commercially made cookies, cakes and pastries and to limit their consumption of dairy products and processed meats.