Many dietitians and scores of books have touted the health benefits of following a Mediterranean diet for some years now, but it was only recently that scientific data has been published to back up their claims. The results of a large-scale 5-year study that was published by the New England Journal of Medicine has found that those who follow the Mediterranean diet have a 30 percent lower risk of death from the effects of cardiovascular disease, such as heart attack and stroke.
The First Major Clinical Study of the Mediterranean Diet
Researchers from the University of Barcelona followed 7,447 people who were deemed to have significant cardiovascular risk factors, such as smoking, diabetes, high blood pressure, high cholesterol, a family history of heart disease and being overweight. The participants were randomized into one of three groups: the first group followed a standard Mediterranean diet, supplemented with olive oil (at least 4 tablespoons per day); the second group followed a standard Mediterranean diet supplemented with nuts (about an ounce per day of a mixture of walnuts, almonds and hazelnuts); and the third group was prescribed a low-fat diet.
Those following the Mediterranean diet were to consume two servings of vegetables and three servings of fruit each day, in addition to eating fish and legumes (such as peas, beans and lentils) at least three times a week. They were also instructed to substitute white meat for red, and if they drank alcohol, were advised to drink at least seven glasses of wine each week, during meals. Perhaps one of the most important points of the diet was that participants were asked to reduce the consumption of commercially baked goods to no more than three times a week, and to limit their intake of dairy products and processed meats.
The low-fat diet group was instructed to avoid eating nuts and any kind of vegetable oil (including olive oil), remove visible fat from meat and limit their consumption of store-bought desserts to less than one per week. They were encouraged to eat three or fewer servings of a simple carbohydrate each day, such as bread, pasta, potatoes or rice, and three servings of low-fat dairy, in addition to fruit and vegetables.
All three groups were given counseling as to how to follow the diet, although the Mediterranean diet group got more counseling early in the study, meeting weekly with a dietitian. The low-fat diet group got instructions at the beginning of the diet and an annual leaflet, but did not get the same counseling until after there had been a significant loss of participants in the group.
There was no limit placed on the number of calories that could be eaten by either group, nor were participants encouraged to increase physical activity. Participants in the low-fat group had the most difficult time sticking to the dietary guidelines and most ended up simply eating a standard Western diet that was only slightly lower in fat than usual. Experts agree that maintaining a low-fat diet is difficult in the long-term, as the dieters never really feel satisfied.
The participants who followed one of the Mediterranean diets were not only 30 percent less likely to have suffered a heart attack, stroke or have died during the study, they were also 40 percent less likely to suffer a stroke in the study’s 4-year follow-up period than those who followed the low-fat diet. The results were consistent across all participants, whether they were male or female, older or younger. The researchers were not looking to reduce the participants’ weight, cholesterol or blood pressure, but instead were interested in counting the number of heart attacks, strokes and deaths from any cause to evaluate the overall effectiveness of the diet on longevity.
How the Mediterranean Diet Benefits the Cardiovascular System
Although the researchers believe that the primary difference between the outcomes of the Mediterranean diet group and the low-fat diet group was the increased consumption of olive oil and nuts, they nevertheless suggest that it is not possible to break down the beneficial elements of the Mediterranean diet into specific components. The researchers noted, “Perhaps there is a synergy among the nutrient-rich foods included in the Mediterranean diet that fosters favorable changes” in factors that lead to cardiovascular disease, such as inflammation, oxidation, cholesterol and insulin resistance. The Mediterranean diet is composed of many parts, all of which help to reduce your risk of death from cardiovascular disease.