Here's another reason to follow the Mediterranean diet

Eating a Mediterranean diet rich in healthy fats from olive oil and nuts provides better protection against heart attack and stroke than a low-fat diet, a new Spanish trial has shown.

This is great news for South Africans. According to the Heart and Stroke Foundation of South Africa, 225 South Africans are killed by heart disease every day. 

"Extensive research has found a significant benefit of eating a Mediterranean diet, and separate research has shown a significant benefit to the consumption of nuts, particularly walnuts, which was the majority of the nuts in this study," said Dr Rachel Bond. She is associate director of Women's Heart Health at Lenox Hill Hospital in New York City.

"This study combines those two factors and shows that, in combination, this dietary modification has a significant benefit to cardiovascular health," Bond continued. "These new results provide further evidence for physicians to educate their patients about how beneficial dietary modification can be in terms of their heart health."

The new report was published online in the New England Journal of Medicine.

The beneficial effects 

In the clinical trial, led by Dr Miguel Angel Martinez-Gonzalez, from the Instituto de Salud in Spain, nearly 7 450 people at high risk of heart disease were assigned to one of three diets, a Mediterranean diet supplemented either with extra-virgin olive oil or with mixed nuts, or a "control" diet focused on reducing fat intake.

Participants were then tracked for about five years to see whether the Mediterranean diet helped protect their heart health. A Mediterranean diet focuses on replacing saturated fats from butter and fatty cuts of meat with healthy unsaturated fats from sources like olive oil, nuts and fatty fish.

About 3.8% of people in the olive oil group and 3.4% of people in the nuts group experienced a stroke or heart attack during the follow-up period, compared with 4.4% of people on a low-fat diet, the investigators found. Analysis revealed that the Mediterranean diet with olive oil reduced risk of a stroke or heart attack by 31%, and the diet with nuts reduced risk by 28%, the study authors said.

Colleen Chiariello is chief clinical dietitian with Northwell Health's Syosset Hospital in Syosset, New York. She said, "The researchers concluded that following a Mediterranean diet with supplemental olive oil or nuts has beneficial effects, especially for high-risk patients trying to prevent cardiovascular events."

And Dr Robert Eckel, director of the Lipid Clinic at the University of Colorado Hospital, in Denver, said that the Mediterranean diet has long been recognised as a heart-healthy diet by the American Heart Association. But Dr Eckel isn't sure this study adds much to the already strong evidence supporting this diet. That's because the low-fat diet control group had been asked to eat less than 30% of their daily calories in fat, which is "not beneficial", he said.

Is the diet affordable?

"The control group was on a low-fat diet that is not anything consistent with current dietary recommendations," Dr Eckel noted. In addition, a Washington, D.C.-based nutritionist, Rebecca Scritchfield, pointed out that the clinical trial took place in Spain, and there are critical lifestyle differences between that more laid-back country and the United States.

"If you're a male in America literally working yourself to death, no amount of salmon or nuts or olive oil is going to save you," said Scritchfield, the author of Body Kindness.

The Mediterranean diet works to protect heart health mainly because it replaces saturated fat with unsaturated fat, Dr Eckel and Scritchfield explained. People still feel the fullness associated with fat, but aren't at risk of having their arteries clogged.

Scritchfield is also concerned about whether poorer people can afford to be on the Mediterranean diet, which involves a lot of healthy whole foods.

"Eating does need to be affordable," she said. "We could be leaving out a group of people if it's an expensive way to eat, because they wouldn't be able to afford the food."

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