MONDAY, Dec. 8 (HealthDay News) -- In older adults at risk for heart disease, a Mediterranean diet plus daily servings of mixed nuts may help manage metabolic syndrome, according to a Spanish study.

Metabolic syndrome describes a group of health problems that includes abdominal obesity, high cholesterol, high blood pressure and high glucose levels -- all of which are risk factors for cardiovascular disease. Previous research suggests that a Mediterranean diet -- which includes lots of cereals, vegetables, fruits and olive oil, moderate consumption of fish and alcohol, and low intake of dairy, meats and sweets -- lowers the risk of metabolic syndrome.

This new study included 1,224 people, ages 55 to 80, at high risk for cardiovascular disease. They were randomly assigned to one of three groups. The control group received advice on a low-fat diet while the other two groups received quarterly education about the Mediterranean diet. One of the Mediterranean diet groups received one liter per week of virgin olive oil, while the other group received 30 grams per day of mixed nuts.

At the start of the study, 61.4 percent of the participants met criteria for metabolic syndrome. After one year, the prevalence of metabolic syndrome decreased by 13.7 percent in the mixed nut group, by 6.7 percent in the olive oil group, and by 2 percent in the control group.

There were no weight changes in any of the groups over the one-year study period. But the number of people with large waist circumference, high triglycerides or high blood pressure significantly decreased in the Mediterranean diet/mixed nuts group compared with the control group. This suggests that the Mediterranean diet with mixed nuts improves certain features of metabolic syndrome, such as oxygen-related cell damage, insulin resistance, and chronic inflammation, the researchers said.

"Traditionally, dietary patterns recommended for health have been low-fat, high-carbohydrate diets, which generally are not palatable. The results of the present study show that a non-energy-restricted traditional Mediterranean diet enriched with nuts, which is high in fat, high in unsaturated fat and palatable, is a useful tool in managing the metabolic syndrome," concluded Dr. Jordi Salas-Salvado, of the University of Rovira i Virgili, and colleagues.

The study was published Dec. 8 in the journal Archives of Internal Medicine.

More information

The U.S. National Heart, Lung, and Blood Institute has more about metabolic syndrome.