Eating a diet rich in fruits and vegetables may mitigate the effects of a gene linked to heart disease, Canadian researchers say.

The research article in Tuesday's issue of the journal PloS Medicine was one of the largest gene-diet interaction studies for cardiovascular disease. A healthy diet could significantly weaken the effect of a heart disease gene variant. Tony Gentile/Reuters

The researchers analyzed the diets of more than 27,000 individuals from five ethnicities — European, South Asian, Chinese, Latin American and Arab — to look at how diet and the 9p21 gene were related in two separate studies.

"We know that 9p21 genetic variants increase the risk of heart disease for those that carry it," said Dr. Jamie Engert, joint principal investigator of the study, who is a researcher in cardiovascular diseases at the Research Institute of the McGill University Health Centre in Montreal.

"But it was a surprise to find that a healthy diet could significantly weaken its effect," he added in a release.

Study participants who lowered their risk thanks to diet ate at least two servings of fruits and vegetables a day.

The investigators divided participants into three groups based on subjective food patterns:

• Oriental (soy sauce, tofu, pickled foods, green leafy vegetables, eggs, and low sugar).
• Western (eggs, meats, fried and salty foods, sugar, nuts, and desserts).
• Prudent (raw vegetables, fruits, green leafy vegetables, nuts, desserts, and dairy products).

The combination of the least prudent diet and two copies of the risk variant (human cells contain two complete sets of chromosomes, one from each parent) was associated with a doubling in risk for heart attack. The findings support public health recommendation to eat more than five servings of fruits and vegetables, said Dr. Sonia Anand. McMaster University

The paper's authors concluded: "There may be an important interplay of genes and environment" in cardiovascular disease.

The findings also support the public health recommendation to eat more than five servings of fruits and vegetables to promote health, they said.

The results also raise the possibility that a sound diet can mediate the effects of 9p21, the journal's editors noted.

Some participants may not have remembered their diet accurately, and there was a small number of cardiovascular cases in one of the studies, the editorial said.

The researchers also acknowledged other limitations of the paper, including differences in diet variables between the two studies, and a small number of individuals of Latin American and Arab compared with other ethnic groups.

The authors did not declare any competing interests.