The current study
examined more than 15,000 people in 39 countries around the world, all with stable heart disease and an average age of 67. Researchers asked about their diet, including how many times a week they consumed servings from food groups such as meat, fish, dairy, whole grains or refined grains, vegetables, fruit, desserts, sweets, sugary drinks, deep-fried foods and alcohol. Participants were given a "Mediterranean diet score," based on consumption of healthy foods, or a "Western diet score," based on consumption of unhealthy foods.
The researchers followed up about four years later to compare how many participants from each diet group had experienced a major adverse cardiovascular event, such as heart attack, stroke or death.
They found that for every 100 people who ate the highest amount of healthy Mediterranean foods, there were three fewer heart attacks, strokes or deaths compared with 100 people who ate the least amount of healthy foods.
After adjusting for other factors that might affect the results, such as smoking and exercise, the study also found that the risk of heart attacks, strokes or death from heart disease was reduced by about one-third for those who follow a Mediterranean diet, said study author Ralph Stewart of Auckland City Hospital and the University of Auckland in New Zealand.
Better to include the good than avoid the bad
Stewart said the results suggest that eating greater amounts of healthy food was more important for people with heart disease than avoiding unhealthy foods.
"The success of the traditional approach to dietary advice, which often (focuses) on avoiding foods which are enjoyed, has been variable," Stewart said. "A clear message to increase healthy foods -- eat three or more servings of fruit and vegetables each day -- could be more successful."
Registered dietitian Lisa Drayer, who was not involved in the study, agrees that it's important to focus on eating healthy foods rather than avoiding unhealthy ones.
"We all need to eat to live," she said. "If you want to break other bad habits, you cut them out of your life: You cut cigarettes, you cut out drugs. But when it comes to food, you can't not eat. It's just as important, if not more important, for everyone to know what they should eat as opposed to what they should steer clear of. Adding certain foods on a regular basis is more achievable as opposed to stripping your diet of everything you like."
Drayer said the Mediterranean diet is consistent with the new U.S. Dietary Guidelines and other diets, such as Dietary Approaches to Stop Hypertension
, which have proved to be protective in terms of disease prevention. She recommends including foods from the Mediterranean diet, such as salmon, fruits, vegetables, whole grains and even a glass of wine, to keep our hearts healthy.
"The diet has proven itself, and it behooves every one of us to eat more fish on a regular basis, to have half of our plate filled with produce and to enjoy the occasional glass of wine," she said. "And the more consistent you are with this type of diet, the more impact it has on your health."
Study isn't a 'green light' for unhealthy foods
The researchers also found that consuming a Western diet did not increase the risk of cardiovascular events. Stewart said this is surprising because such a diet includes foods known to increase the risk of obesity.
Although the study didn't find an association with the Western diet, Drayer said it's still important to limit processed and fried foods, since they've been shown to increase weight gain, cholesterol and heart disease risk.
The study does have some limitations, as it relied on people's memories of what they ate, and the questionnaire didn't define a serving size. The study was also part of a drug trial, but the findings of this study were not related to the drug.
Stewart and Drayer both caution that these new findings don't mean people can consume unhealthy foods without restrictions.
"This study should not give people the green light to go ahead and eat large portions of sugary foods and beverages and deep-fried foods," Drayer said. "But this study shows that it's never too late to make changes in your diet, and it can be particularly beneficial to include healthy foods."