People whose genes put them at risk for heart disease may be able to do something to combat their heredity — eat plenty of fruits and vegetables.

In a new study, people with alterations in a gene called 9p21 had an increased risk of having a heart attack. But if they ate a diet high in raw fruits and vegetables, that increase was virtually eliminated.

The study is one of the largest to examine the interaction between genes and diet and its findings suggest that, although our genes may increase the risk of certain diseases, our diet may mitigate this effect.

"It's exciting to observe that, potentially, we can turn off a high-risk gene by a dietary change," said study researcher Sonia Anand, a professor of medicine and epidemiology at McMaster University in Ontario, Canada.

The study appears today (Oct. 11) in the journal PLoS Medicine.

Genes and heart attack risk

Anand and colleagues examined the genomes of 8,114 people of five ethnicities: European, South Asian, Chinese, Latin American and Arab. About half had experienced a heart attack.

Certain "risk markers" within the 9p21 gene were associated with an increased risk of heart attack. Those with risk markers were about 1.2 times more likely to suffer a heart attack than those without any of these markers.

However, the quality of a person's diet changed this risk.

Those with the genetic risk who ate more than two servings of fruits and vegetables a day had about the same risk of heart attack as those without the genetic risk.

And those with the genetic risk who ate a diet low in fruits and vegetables were 1.3 times more likely to have a heart attack than those who had the genetic risk but ate a diet high in fruits and vegetables.

The researchers confirmed their findings in another sample of more than 19,000 Finnish citizens. They found that a diet high in fruits, vegetables and berries reduced the risk of cardiovascular disease in those with the genetic risk for heart disease.

Changing diet
Future research should investigate exactly how fruits and vegetables act on genes to change a person's risk of heart disease, the researchers said. A recent study published in the journal Cell Research found that genetic material within plants can survive digestion in the stomach and alter gene expression in mice. However, it's not clear if this happens in people.

The new findings might provide additional motivation for people to change their diet. While public health officials have been telling us to eat more fruits and vegetables for years, not many people do, Anand said.

"Perhaps this would be almost a motivational tool to know that, genetically, you're at increased risk of a heart attack, and this can be reduced by consuming more fruits and vegetables," Anand said.

Pass it on: A healthy diet may counteract the effect of genes that put us at risk of heart disease.