A new study reports that eating a traditionally Mediterranean diet including lots of mixed nuts may help prevent metabolic syndrome, which is a good predictor of heart disease. Metabolic syndrome includes high blood pressure, fat in the abdominal area, and high cholesterol and blood glucose levels — keeping these factors in check can lead to better cardiovascular health.

Nuts may be helpful in combating metabolic syndrome by working to reduce common factors like insulin resistance, oxygen-related cell damage, and chronic inflammation.

Researchers at the University of Rovira i Virgili in Spain wished to put the Mediterranean diet to the test, since it has been associated with better heart health in the past. The Mediterranean diet is high in fruits, vegetables, cereals, olive oil, moderate in fish and alcohol, and low in sweets and other animal products.

The team studied 1,224 participants (ages 55-80) who were already at risk for heart disease and randomly divided them into groups: one was told to keep to a low-fat diet, and two groups were educated quarterly about the typical Mediterranean diet. One of these two groups was given a liter of olive oil every week and the other was given an assortment of mixed nuts every day (30 grams). The researchers asked participants not to change their normal exercise routines.

After one year of following their respective diets, changes in the participants' heart health were assessed. Researchers found that while nobody's weight changed throughout the study, the occurrence of metabolic syndrome decreased 13.7% in the Mediterranean diet/mixed nut group, 6.7% in the Mediterranean/olive oil group, and only 2% in the low-fat group. The prevalence of large waste-lines, high cholesterol, and high blood triglyceride levels all decreased in the Mediterranean diet/mixed nut group. The researchers say that nuts may be helpful in combating metabolic syndrome by working to reduce common factors like insulin resistance, oxygen-related cell damage, and chronic inflammation.

Lead researcher Jordi Salas-Salvadó points out that in the past, "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." The team also says that to assess the longer-term benefits of the Mediterranean diet, a follow-up study on these participants would be very useful.

The study was published in the December 8/22 issues of the journal Archives of Internal Medicine.