You're right. For some years we have believed the Mediterranean diet to be heart protective. But this new study has come up with even more impressive findings. It has demonstrated that the diet can cut the rate of heart disease, stroke, and death from heart disease by as much as 30 percent, even among men and women considered at high risk because they were smokers, overweight, had diabetes, high blood pressure, high cholesterol levels or other risk factors for heart disease. One earlier study showed that people who ate a Mediterranean-style diet had a 33 percent reduction in the risk of death from heart disease, as well as a death rate from cancer that was 24 percent lower than those who followed other eating practices. In addition, in 2001, the Lyon Diet Heart Study found that the Mediterranean diet reduced the rates of heart disease recurrence and cardiac death among patients who already had had heart attacks by 50 to 70 percent when compared with the American Heart Association diet.
The Mediterranean diet focuses on a composite of the traditional cuisines of Spain, southern France, Italy, Greece, Crete and parts of the Middle East. For the newly published study, researchers at the University of Barcelona in Spain randomly assigned nearly 7,500 people considered at high risk of heart disease to follow the Mediterranean diet or a low-fat diet for five years. Participants were men 55 to 80 years of age and women ages 60 to 80. The research team divided the participants into three groups. One group followed a low-fat diet while the other two groups followed two slightly different versions of the Mediterranean diet. One of these two groups was given a supply of extra-virgin olive oil each week, and participants were instructed to use at least four tablespoons per day; instead of olive oil, the other group received a combination of nuts – walnuts, almonds and hazelnuts – and were told to eat about an ounce (about one-quarter cup) per day. Both groups were also told to eat at least three servings of fruit and two servings of vegetables per day, fish at least three times a week, and legumes (beans, peas and lentils) at least three times a week. Those who drank alcohol were encouraged to have one glass of wine per day. Participants in the two Mediterranean diet groups were also urged to limit their consumption of dairy products and processed meats and to avoid commercially produced baked goods, such as cookies, cakes and pastries.
At the five-year mark, the researchers determined that the participants who followed both versions of the Mediterranean diets were 28 to 30 percent less likely to develop cardiovascular disease than those on the general low-fat diet, results that support the benefits of the Mediterranean diet for prevention of cardiovascular disease. The study was published on February 25, 2013 in the New England Journal of Medicine.
To verify that the participants were sticking to their version of the Mediterranean diet, the research team tested the participants’ urine for a marker that indicates consumption of olive oil and used a blood test to check for alpha-linolenic acid, an indicator of nut consumption. Participants in the group assigned to a low-fat diet were not very successful in sticking to their plan.
We still don’t know for sure if the Mediterranean diet would work as well to protect people who are at low risk of heart disease, but the New York Times reported that the researchers themselves have switched to Mediterranean eating.
Andrew Weil, M.D.
Learn more about the Mediterranean diet in this video.