People who eat a Mediterranean diet high in olive oil or nuts may reduce their likelihood of developing clogged leg arteries, according to new research from Spain.
The finding follows results from the same trial published last year that showed sticking to a Mediterranean diet could lower the risk of heart attack and stroke (see Reuters Health story of February 25, 2013 here: reut.rs/1hxUexN).
"Now we have this very strong reduction in the risk of peripheral artery disease," Dr. Miguel Martínez-González, from the University of Navarra in Pamplona, told Reuters Health. "This is very reassuring."
Peripheral artery disease arises when plaque builds up in the arteries that carry blood to the legs and feet, restricting blood flow. The condition often causes leg pain and fatigue, especially during walking.
The current trial, Martínez-González said, is the first to randomly assign people without heart disease to a Mediterranean or other diet and see how they fare.
He and his colleagues allocated 7,477 older Spaniards to one of three diet plans: a Mediterranean-style diet supplemented with extra-virgin olive oil, a Mediterranean diet with extra nuts or a standard low-fat diet.
Participants met with a dietician four times each year to review their eating habits and set goals for how to follow their prescribed diet more closely. The researchers also gave them shopping lists, menus and recipes as well as free olive oil or nuts for those assigned to the Mediterranean diets.
Although none of the participants had heart disease at the start of the study, all were deemed to be at risk because they had diabetes or a combination of other risk factors.
Over an average of almost five years, 89 people in the study developed peripheral artery disease. That included 18 in the olive oil group, 26 in the nuts group and 45 in the low-fat comparison group, the researchers wrote in the Journal of the American Medical Association.
They found the Mediterranean diet supplemented with olive oil cut people's risk of peripheral artery disease by 64 percent, and the one with extra nuts cut the risk in half.
But because the condition was relatively rare, they calculated that more than 300 people would have to eat a Mediterranean-style diet instead of a low-fat one to prevent one case of peripheral artery disease.
The authors cautioned that because they didn't originally set out to measure the risk of peripheral artery disease, their study is just a first shot at looking at how it may be influenced by diet.
Andrew Gardner, who has studied diet and peripheral artery disease at the University of Oklahoma Health Sciences Center in Oklahoma City, agreed that's a limitation of the new study. It also only counted the disease in people who had symptoms, he noted.
"At least it's a step in the right direction recognizing that diet may have an important role in developing peripheral artery disease and then certainly once you have it, it may affect the way the symptoms progress," Gardner, who wasn't involved in the new research, told Reuters Health. "This is a study that is very timely and long overdue."
Martínez-González said it makes sense that if a Mediterranean diet can reduce the risk of heart attack and stroke, it can affect other diseases related to clogged arteries - possibly by lowering inflammation and improving cholesterol numbers.
"From a biological, mechanistic point of view, the underlying disease process for peripheral artery disease is exactly the same as for stroke or (heart attack). It is atherosclerosis, or disease of the arteries," he said.
When it comes to adopting a Mediterranean-style diet, Martínez-González suggested people start with what's easiest for them - like drinking a glass of red wine each night or eating more vegetables prepared with olive oil. Other healthy changes include substituting poultry and fish for red meat and having fruit for dessert instead of sweets on most days, he said.