A Mediterranean diet includes a high proportion of fruit, vegetables, fish, and unrefined foods. A Western diet contains refined grains, sweets, desserts, sugared drinks, and deep-fried food.
The new research shows that the Mediterranean diet can decrease the risk of heart attack and stroke in people who already have heart disease.
At the same time, it suggests that if people avoid the unhealthy aspects of a Western diet, they also avoid worsening their risk of cardiac problems.
Guidelines from the American Heart Association (AHA) recommend frequent consumption of fruit, vegetables, fish, and other whole foods, say the authors of the current report.
Researchers – led by Prof. Ralph Stewart from Auckland City Hospital at the University of Auckland in New Zealand – looked at data for 15,482 people with stable coronary artery disease in 39 countries worldwide.
Fewer heart attacks among those who eat Mediterranean foods
Participants were aged 67 years on average, and the team followed them up for nearly 4 years.
Results show that for every 100 people eating the highest proportion of healthy Mediterranean foods, there were three fewer heart attacks, strokes, or deaths than among the 100 people with the lowest intake of healthy foods.
The subjects were part of a trial called STABILITY, which aimed to evaluate the effectiveness of a drug called darapladib in reducing heart attacks, strokes, and death.
Fast facts about heart disease
According to the Centers for Disease Control and Prevention (CDC), heart disease is the number one killer for both men and women in the United States
Around 610,000 Americans die of heart disease each year
Someone in the U.S. has a heart attack every 43 seconds.
Learn more about heart disease
Participants completed a questionnaire, in which they provided information about their diet. Details included how many times a week they ate whole grains or refined grains, meat, fish, dairy foods, fruit, desserts, sweets, sugary drinks, deep-fried foods, vegetables – except for potatoes – and how frequently they drank alcohol.
Based on this information, each person received a “Mediterranean diet score” (MDS). The greater the proportion of healthy foods they ate, the higher was the score they received. The total range of scores was from 0-24.
A “Western diet score” (WDS) gave points according to how much unhealthy food each person ate.
At the end of the 3.7-year study period, 1,588 people, or 10 percent of all participants, had experienced a major adverse cardiovascular event (MACE), whether a heart attack, stroke, or death.
The group that ate the highest proportion of healthy foods scored over 15 MDS points. Of these, 2,885, or 7.3 percent, experienced a MACE.
As the MDS score fell, the likelihood of a person experiencing a MACE went up.
An MDS score of 13-14 points was given to 2,855 people, and 10.5 percent of these had a MACE. Among the 8,579 people with an MDS score of 12 or lower, 10.8 percent had a MACE.
The pattern was consistent regardless of location and income levels.
After adjustments for other factors, with each unit increase in the MDS an individual with existing heart disease had a 7 percent lower risk of heart attack, stroke, or death from cardiovascular or other causes.
Meanwhile, the authors were surprised to note that eating more “Western” foods, considered to be less healthy, did not appear to increase the risk.
“The research suggests we should place more emphasis on encouraging people with heart disease to eat more healthy foods, and perhaps focus less on avoiding unhealthy foods.”
Prof. Ralph Stewart
He notes that while fruit and vegetables appear to reduce the risk of a heart attack or a stroke, small amounts of refined carbohydrates, sugar, deep fried food, and desserts do not appear to cause additional harm.
Prof. Stewart notes that the benefit of foods such as fruits and vegetables in protecting against heart disease is “not explained by traditional risk factors such as good and bad cholesterol or blood pressure.”
Study highlights dietary trends, despite limitations
Limitations of the current study include the fact that the assessments were “relatively crude,” so the authors say that there may be some harm in eating unhealthy foods.
Nor was there any assessment of total calorie intake, or of good and bad fats, although these factors may have an impact on obesity-related health problems.
In addition, the survey deliberately left it to the individual to decide what constitutes a “serving,” in order to make the process easy for respondents.
Participants were able to interpret a serving as a piece of fruit, or a portion of meat, grains or vegetables that would be appropriate for one person.
According to Prof. Stewart, this showed that scientists can identify a dietary pattern associated with a lower risk of recurrent heart attacks or strokes by using a few simple questions.
Prof. Stewart advises people to prioritize fruit and vegetables, because they may lower the risk of cardiovascular problems.
Learn about how a Mediterranean diet may protect against brain aging.
Written by Yvette Brazier