Dr. Jordi Salas-Salvado of the University of Rovira i Virgili in Spain and colleagues assessed 1,224 participants ages 55-80 and at high risk for cardiovascular disease. Participants were randomly assigned to one of three groups: one group received advice on a low-fat diet while two received quarterly education about the Mediterranean diet. One of the Mediterranean diet groups was provided with 1 liter per week of virgin olive oil and the other received 30 grams per day of mixed nuts.
At the beginning of the study, 61.4 percent of the participants met criteria for the metabolic syndrome -- abdominal obesity and high cholesterol, high blood pressure and high blood glucose levels, risk factors for cardiovascular disease.
The prevalence of metabolic syndrome decreased by 13.7 percent among those in the Mediterranean diet plus nuts group, 6.7 percent in the Mediterranean diet plus olive oil group olive oil group and 2 percent in the control group.
The study, published in the Archives of Internal Medicine, also found that the weight of the study participants did not change over the one-year period, however, the number of individuals with large waist circumference, high triglycerides or high blood pressure significantly decreased in the Mediterranean diet plus nuts group compared with the control group.