BARCELONA, SPAIN – Results from a study in Spain support the benefits of the Mediterranean diet for the primary prevention of cardiovascular disease. According to the study appearing on-line Feb. 25 in The New England Journal of Medicine, researchers observed an energy-unrestricted Mediterranean diet, supplemented with extra-virgin olive oil or nuts, resulted in a substantial reduction in the risk of major cardiovascular events among high-risk people.

The researchers defined a traditional Mediterranean diet as a high intake of olive oil, fruit, nuts, vegetables and cereals; a moderate intake of fish and poultry; a low intake of dairy products, red meat, processed meats and sweets; and wine in moderation consumed with meals.

The study included men of the ages 55 to 80 and women of the ages 60 to 80. Nobody had cardiovascular disease at enrollment, but everybody had either type 2 diabetes or at least three of the following risk factors: smoking, hypertension, elevated L.D.L. “bad” cholesterol levels, low H.D.L “good” cholesterol levels, overweight or obesity, or a family history of premature coronary heart disease.

Beginning on Oct. 1, 2003, 7,447 people were assigned randomly to one of three diets on a 1:1:1 ratio. People on one Mediterranean diet were given about 1 liter of extra-virgin olive oil per week. People on another Mediterranean diet were given 30 grams of mixed nuts per day. The 30 grams consisted of 15 grams of walnuts, 7.5 grams of hazelnuts and 7.5 grams of almonds. People in the third diet, a control diet, received advice on a low-fat diet.

The people were followed for a median of 4.8 years.

In the study, an energy-unrestricted Mediterranean diet supplemented with extra-virgin olive oil or nuts resulted in a relative risk reduction of major cardiovascular events of about 30% among high-risk persons who were initially free of cardiovascular disease. The risk of stroke was reduced significantly in the two Mediterranean diet groups.

Instituto de Salud Carlos III, the official funding agency for biomedical research of the Spanish government, supported the study.