By Kathleen Doheny
MONDAY, Feb. 25 (HealthDay News) -- Score another heart-health win for the Mediterranean diet.
Eating a diet rich in olive oil, nuts, fresh fruits and vegetables, along with red wine, helped those at high risk for cardiovascular problems avoid heart trouble better than those eating a low-fat diet, a new Spanish study has found.
During a follow-up period of about five years, study participants on a Mediterranean diet that emphasized either olive oil or nuts had a 30 percent greater reduction in relative risk of a heart attack, stroke or death from cardiovascular disease, said study lead author Dr. Miguel Angel Martinez-Gonzalez. He is chairman of preventive medicine and public health at the Universidad de Navarra in Spain.
"This is a moderate-to-high benefit," he said. "The low-fat diet also helped, but to a lesser degree."
The new findings are published online Feb. 25 in the New England Journal of Medicine. They will also be presented this week at the International Congress on Vegetarian Nutrition in Loma Linda, Calif.
The findings echo those from previous research.
Martinez-Gonzalez's team evaluated nearly 7,500 men and women. They ranged in age from 55 to 80 when they enrolled in the study, which began in Spain in 2003. Fifty-seven percent of the participants were women.
While the men and women had no history of heart attack or stroke or other cardiovascular problems at enrollment, they did have risk factors such as type 2 diabetes, smoking, high blood pressure or high cholesterol.
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The researchers assigned the men and women to one of three groups -- a low-fat diet, a Mediterranean diet that focused on nuts or a Mediterranean diet that focused on olive oil.
On average, the men and women were overweight or obese. In all three groups, the average body-mass index was 30 or close to it, which is defined as obese.
The olive oil group consumed about a liter -- roughly 34 ounces -- of olive oil a week. The nuts group ate about one ounce of nuts a day, including walnuts, hazelnuts and almonds. Members of both groups also ate plenty of fruits and vegetables, as well as fish, and drank wine with meals. They could have white meat but were told to avoid red and processed meats.
[See Best Plant-Based Diets]
The low-fat group ate low-fat dairy, breads, potatoes, fruits and vegetables and lean fish. They were told to avoid oils, baked goods, nuts, red and processed meat and fatty fish.
At the end of the study, 288 cardiovascular events had occurred. While 109 of those events occurred in the low-fat group, 96 were in the group that ate a Mediterranean diet with olive oil, and 83 were in the Mediterranean diet-with-nuts group.
When the researchers looked separately at stroke, heart attack and death, only the link between the Mediterranean diet and stroke was statistically significant. The researchers found a link between the diets and heart protection, but it did not prove cause and effect, they said.
So why does the Mediterranean diet seem to boost heart health? Martinez-Gonzalez said it's probably the combination of good-quality fats -- both monounsaturated like olive oil and polyunsaturated like vegetable oils -- and the wide range of other nutrients.
The findings came as no surprise to two U.S. experts.
"I think this is demonstrating again, conclusively, that this is the diet to go on to prevent heart disease," said Dr. Suzanne Steinbaum, director of women and heart disease at Lenox Hill Hospital in New York City, and a spokeswoman for the American Heart Association's Go Red for Women campaign.