A heart-healthy diet rich in fruits, vegetables and fish significantly reduces the chance of a second heart attack and stroke in people with cardiovascular disease, McMaster University researchers have found.

A five-year study of almost 32,000 patients (average age 66.5 years) in 40 countries discovered those who ate a heart-healthy diet had a:

    35 per cent reduction in risk for cardiovascular death
    14 per cent reduction in risk for new heart attacks
    28 per cent reduction in risk for congestive heart failure
    19 per cent reduction in risk for stroke

"At times, patients don't think they need to follow a healthy diet since their medications have already lowered their blood pressure and cholesterol -- that is wrong," said Mahshid Dehghan, the study's lead author and nutritionist at McMaster University's Population Health Research Institute (PHRI). "Dietary modification has benefits in addition to those seen with Aspirin, angiotensin modulators, lipid-lowering agents and beta blockers."

The study is posted online in the American Heart Association journal Circulation.

Each year, at least 20 million people worldwide survive a heart attack or stroke. While drug treatments, such as Aspirin, substantially lower their risk of another heart attack, the McMaster study is the first to show a high quality diet also significantly lowers their risk.

For the study, researchers assessed the association between diet quality and the risk of cardiovascular disease using information collected from men and women who participated in two major McMaster-led global studies: ONTARGET, and TRANSCEND.

Participants with cardiovascular disease were asked how often they consumed milk, vegetables, fruits, grains, fish, nuts, meat and poultry over the past 12 months. They were also asked about lifestyle choices such as alcohol consumption, smoking and exercise. A healthy diet was indicated by a high intake of fruits, vegetables, whole grains and nuts as well as a high intake of fish compared to meat, poultry and eggs.

Researchers found a heart-healthy diet offered a "consistent benefit" over and above the benefits of taking medications to reduce the risk of heart attack and stroke.

Globally, healthy eating was associated with a lower risk of cardiovascular disease by more than 20 per cent in all regions of the world, which were grouped based on their food habit. According to income, similar results were found in middle and high income countries in different regions of the world.

The researchers believe this is the first study to report on the protective impact of healthy eating for individuals with cardiovascular disease who are taking medication to prevent a second heart attack, stroke or death.

"Physicians should advise their high-risk patients to improve their diet and eat more vegetables, fruits, grains and fish," Dehghan said. "This could substantially reduce cardiovascular recurrence beyond drug therapy alone and save lives globally."

Boehringer Ingelheim funded the study.