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A Traditional Mediterranean Diet May Prevent Heart Attacks, Strokes, And Deaths from Heart Disease

By: Barbara Sadick

A traditional Mediterranean diet may prevent about 30 percent of heart attacks, strokes, and deaths from heart disease, according to a New England Journal of Medicine study published online on February 25, 2013.

The Mediterranean diet recommends primarily eating plant-based foods such as fruits and vegetables, legumes, whole grains, and nuts. Some fish and poultry, and moderate amounts of wine are allowed, but dairy, red meat, processed meats, and sweets are limited. Butter should be replaced with healthy fats such as olive and canola oil, and herbs and spices should be used instead of salt to flavor foods.

This study, part of the PREDIMED study, which began in 2003 and assembled research groups involved in studying nutrition and cardiovascular risks in Spain, was a large randomized clinical trial of dietary intervention meant to evaluate whether the Mediterranean diet supplemented with extra-virgin olive oil or nuts prevents cardiovascular disease as compared to a normal low-fat diet composed of rice, fruits, vegetables, fish, bread, and potatoes.

Led by Dr. Ramon Estruch and other researchers from the University of Barcelona in Spain, the study randomized 7,447 people ages 55-80 into three groups.  All participants were free of cardiovascular disease at the start of the study, but were at high risk because they had either type 2 diabetes or three cardiovascular risk factors such as smoking, hypertension, or obesity. 

Study participants were randomly placed into one of three groups.  The first ate a Mediterranean diet supplemented with extra virgin olive oil.  The second also ate a Mediterranean diet supplemented with nuts, while the third ate a traditional low-fat diet and basically served as the control or comparison group.

The majority or 57 percent of the participants were women.  Many of both sexes were overweight or obese, and those who had pre-existing conditions were randomized equally to each of the three groups, ensuring a fair and accurate assessment.  Because the goal of the diet wasn’t   to lose weight, there were no rigid menus or calorie intake limits.

When the study ended early after five years due to its enormous success, both versions of the Mediterranean diet showed a substantial reduction in the risk of cardiovascular disease when compared to the low fat or control group.  Of the 7 percent who had dropped out of the study, the majority had been in the low-fat diet group.  This may have been because during the first half of the study, the control group wasn’t being monitored as intensely as the Mediterranean diet groups who were watched carefully to ensure they had extra virgin olive oil and extra nuts every day.  Half way through the study, though, the low-fat group received more intense oversight to keep them interested.

Robert Ostfeld, MD, Cardiologist and Co-Director of the Cardiac Wellness Program at Montefiore Medical Center in New York City, says the study findings support his belief that our

Western-style diet is a very unhealthy one.  He says that were we to adopt other diets, including the Mediterranean diet, we could be a country with much less cardiovascular disease..  “Our western style diet,” he says, “is made up of a lot of processed foods, animal fat, and very few fruits and vegetables.”

Ostfeld has been enrolling patients into his Cardiac Wellness Program at Montefiore where they’re making a transition from consuming a typical American diet to eating a whole-food, plant-based diet. “We have been humbled and awestruck by the results,” he says.

Kathy McManus, Director of the Department of Nutrition at Brigham and Women’s Hospital in Boston, says the design of this study was excellent, as was the data collected.  “It shows us once again,” she says “the importance of healthy eating patterns to prevent disease and gives us more support to help people do what they have to do to prevent cardiovascular disease.”