While this is far from the first paper to find a connection between the Mediterranean diet and heart health, it is unique because of its large size and design. It randomized a group of more than 7,000 people at high risk of heart disease to follow either one of two kinds of Mediterranean diets (one supplemented with olive oil and one with nuts) or a low-fat diet. This is the most powerful way to show that the diet itself was causing the differences in health outcomes. (Other research includes mainly observational studies showing that people from Mediterranean countries have less heart disease, which could be due to factors besides diet, notes the New York Times.)
In fact, the benefits of following the Mediterranean diet were so powerful that the trial was ended early, after five years, because it was deemed unethical to continue.
The subjects in the study, men and women between ages 55 and 80, had either type 2 diabetes or at least three major risk factors for heart disease, such as smoking, obesity, high blood pressure, high LDL cholesterol or low HDL cholesterol.
So what did they eat, exactly? The two groups of Mediterranean dieters were encouraged to eat fish and legumes three times a week, eat white meat instead of red, and avoid processed cookies and cakes. One group was told to use at least four tablespoons of extra virgin olive oil daily; the other was encouraged to eat an ounce of nuts each day. The low-fat dieters, it turned out, actually didn’t lower their fat intake much. They basically ate their usual diet, including red meat, soda, and processed foods.
Compared with the group on the low-fat diet, the olive oil group had a 30 percent lower risk of heart attack, stroke or dying of heart disease after five years. Those in the nuts group had a 28 percent lower risk.
“The strength of this study comes from the fact that we measured hard outcomes and not just blood pressure or changes in cholesterol levels,” study author Ramón Estruch, from the Department of Internal Medicine at the Hospital Clinic of Barcelona, told Time.com. “We really believe the Mediterranean diet lowers incidence of [heart attack], stroke and cardiovascular deaths.”
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Photo Credit: Duncan Smith