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Eating vegetables raw or lightly steamed is a healthier option than boiling. ((Eric Risberg/Associated Press))

Eating a Mediterranean diet rich in vegetables and nuts does help protect the heart, a new review concludes.

"We took this on because there is a lot of confusion out in the public about what we should eat and what we should avoid eating in terms of preventing a heart attack," study co-author Dr. Sonia Anand of McMaster University in Hamilton, Ont., told CBC News on Tuesday.

"So the good thing is, we can say try and eat more like someone who would live in Greece or Italy, the Mediterranean diet, and try and avoid a Western-type of diet, which is your eggs and bacon breakfast or your hot dogs for lunch."

The review, which appears in Monday's Archives of Internal Medicine, analyzed nearly 200 studies involving millions of people published between 1950 and June 2007.

The Mediterranean diet involves high consumption of:

  • Vegetables.
  • Legumes.
  • Fruits.
  • Nuts that are not roasted or salted.
  • Cheese or yogurt.
  • Whole grains.
  • Fish.
  • Monounsaturated fats such as olive oil and avocados.

The research also confirmed that trans-fatty acids are associated with an increased risk of heart disease.

Starchy carbs such as white bread, white rice and white potatoes that are high on the glycemic index were also linked to an increased risk of heart disease.

'Several simple good things'

Colourful vegetables seem to be better for us than non-colourful vegetables, said Anand, who suggested that people eat a variety of fruits and vegetables.

They found little strong evidence showing benefits or harm of foods such as meats, butter, eggs and other high-fat dairy products.

Anand said she hoped the "strong evidence categories" for both protective and harmful foods will help people choose what to eat, and help dietitians and physicians counsel patients, rather than telling people to avoid certain types of fat.

To rank the foods, Anand's team used criteria developed by Sir Austin Bradford Hill, the late British scientist who helped establish the link between smoking and lung cancer.

Commenting on the review, Jean-Pierre Despres of the Quebec Heart and Lung Institute said the research was well done and systematic.

"It's another opportunity … to emphasize to the Canadian population there's no miracle single thing in what we eat that is going to cure diabetes and heart disease," he said from Quebec City.

"It's a little bit of several simple good things."

The Heart and Stroke Foundation of Canada and the Canadian Institutes of Health supported the research.

With files from The Canadian Press, Associated Press