A Mediterranean diet high in olive oil, nuts, fish and fresh
fruits and vegetables may help prevent heart disease and
strokes, according to a large study from Spain.
Past research suggested people who eat this type of diet have
healthier hearts, but those studies couldn't rule out that
other health or lifestyle differences had made the
But for the new trial, written up in the New England Journal
of Medicine, researchers randomly assigned study volunteers
at risk of heart disease to a Mediterranean or standard
low-fat diet for five years, allowing the team to single out
the effect of diet in particular.
"This is good news, because we know how to prevent the main
cause of deaths - that is cardiovascular diseases - with a
good diet," said Miguel Angel Martinez-Gonzalez, who worked
on the study at the Universidad de Navarra in Pamplona.
He and colleagues from across Spain assigned almost 7,500
older adults with diabetes or other heart risks to one of
Two groups were instructed to eat a Mediterranean diet - one
supplemented with extra-virgin olive oil and the other with
nuts, both donated for the study - with help from
personalized advice and group meetings. The third study group
ate a "control" diet, which emphasized low-far dairy
products, grains and fruits and vegetables.
Over the next five years, 288 study participants had a heart
attack or stroke, or died of any type of cardiovascular
People on both Mediterranean diets, though, were 28 to 30
percent less likely to develop cardiovascular disease than
those on the general low-fat diet, the researchers said.
The new study is the first randomized trial of any diet
pattern to show benefit among people initially without heart
disease, said Dariush Mozaffarian, who studies nutrition and
cardiovascular disease at the Harvard School of Public
It's the blend of Mediterranean diet components, and not one
particular ingredient, that promotes heart health, according
"The quality of fat in the Mediterranean diet is very good,"
he told Reuters Health. "This good source of calories is
replacing other bad sources of calories. In addition, there
is a wide variety of plant foods in the Mediterranean diet,"
he added, including legumes and fruits as desserts.
He suggested that people seeking to improve their diet start
with small changes, such as forgoing meat one or two days a
week, cooking with olive oil and drinking red wine with meals
rather than hard alcohol.
Replacing a high-carbohydrate or high-saturated fat snack
with a handful of nuts is also a helpful change, experts
"I think it's a combination of what's eaten and what's not
eaten," said Mozaffarian, who wasn't involved in the study.
"Things that are discouraged are refined breads and sweets,
sodas and red meats and processed meats.
"The combination of more of the good things and less of the
bad things is important."
Teresa Fung, a nutrition researcher at Simmons College in
Boston, said that many people in the trial were already on
medications, such as statins and diabetes drugs.
"The way I see it is, even if people are on medication
already, diet has substantial additional benefit," she added.
"This is a high-risk group, but I don't think people should
wait until they become high-risk in order to change."