LONDON, ENGLAND - Adding nuts to a traditional Mediterranean diet rich in fruit and vegetables appears to provide extra health benefits, Spanish researchers said on Monday.

A daily serving of mixed nuts helped a group of older people manage their metabolic syndrome, a group of related disorders such as obesity, high cholesterol, high blood pressure and abnormal blood sugar, Jordi Salas-Salvado of the University of Rovira i Virgili in Spain and colleagues said.

"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," they wrote in the Archives of Internal Medicine.

The findings add to existing evidence of the health benefits of a Mediterranean diet that emphasizes vegetables, fish and healthy fats such as olive oil over red meat and alcohol. Studies have linked the diet to reduced risk of diabetes, asthma and a range of other conditions.

The researchers looked at 1,224 people in Spain aged 55 to 80 at high risk of heart disease. One group received advice on a low-fat diet while two others followed a Mediterranean diet, one getting an extra liter of olive oil per week and the other receiving an additional 30 grams of mixed nuts daily.

At the start of the study nearly two thirds of the men and women met the criteria for metabolic syndrome, but after one year the condition decreased by about 14 percent among those who ate nuts compared with 7 percent in the olive oil group and 2 percent in the control group on a low-fat diet.

Nuts contain beneficial nutrients such as fiber, arginine, potassium, calcium and magnesium, as well as a high level of unsaturated fats similar to olive oil, the researchers noted.