A traditional Mediterranean diet that includes a healthy serving of nuts each day may help reverse a cluster of risk factors for heart disease, researchers reported Monday.
In a study of more than 1,200 older adults, Spanish researchers found that those who followed the diet had lower rates of metabolic syndrome -- a clustering of risk factors for heart disease, diabetes and stroke, which includes high blood pressure, abdominal obesity, elevated blood sugar and unhealthy cholesterol levels.
The prevalence of metabolic syndrome among the men and women who followed the nut-enriched Mediterranean diet fell by nearly 14 percent over one year compared with roughly 7 percent among study participants who followed a traditional Mediterranean diet rich in olive oil.
In a third study group that received advice to follow a low-fat diet, the prevalence of metabolic syndrome dipped by only 2 percent.
The findings suggest that the Mediterranean diet can help manage metabolic syndrome, even without weight loss or exercise, the researchers report in the Archives of Internal Medicine.
They also imply that the benefits may be greater when people use nuts as a major fat source, according to the investigators, led by Dr. Jordi Salas-Salvado of the University of Rovira i Virgili in Reus.
Both study groups on the Mediterranean diet increased their intake of extra- virgin olive oil, and research has shown olive oil to have cardiovascular benefits.
However, the researchers point out, unlike olive oil, nuts are "whole foods" that provide nutrients other than healthy fats -- including fiber, potassium, calcium and magnesium. Walnuts also contain substantially more of heart-healthy omega-3 fat than olive oil does.
Those nutrients have been shown to reduce blood pressure, cholesterol and inflammation, and improve the body's use of insulin, a hormone that regulates blood sugar.
The study involved 1,224 older adults at high risk of cardiovascular disease, 61 percent of whom had metabolic syndrome at the study's start. The participants in both Mediterranean groups also participated in periodic sessions on how to change their diets -- including advice on cooking with olive oil, replacing red meat with white meat and fish, and eating more fruits and vegetables.
After one year, Salas-Salvado's team found, there were no significant weight changes in any of the groups, on average. However, there were reductions in the various components of the metabolic syndrome -- most apparent in those who boosted their nut intake.
A longer-term follow-up is now needed, the researchers say, to see if the Mediterranean diets prevent heart attacks and other complications of metabolic syndrome.
SOURCE: Archives of Internal Medicine, December 8/22, 2008.