Oct. 11, 2011 -- We know that eating a very healthy diet appears to make heart disease less likely, but now that even goes for people whose genes put them at a higher than normal risk of heart trouble.
"A diet high in fruits and vegetables appears to mitigate the genetic risk of a heart attack," says researcher Sonia S. Anand, MD, PhD, professor of medicine and epidemiology at McMaster University in Hamilton, Ontario, Canada.
The finding, if it bears out, could affect many people at risk for heart disease because of a genetic variant that researchers have only recently linked with heart attack. It could also call into question the suggestion that you can't help your genes.
In general, about 50% of people carry one copy of the bad gene and 20% carry two copies, Anand tells WebMD.
The study is published in PLoS Medicine.
Can Diet Trump Genes?
Anand and colleagues evaluated how diet could affect variants in the chromosome 9p21 region. In 2007, scientists from several countries found variants in this 9p21 area highly linked with heart disease and heart attack.
Since the initial reports, other groups confirmed the link. Some people have one copy of the gene variant. Others have two copies, and their risk of heart disease is thought to be even higher.
"We are confident the gene associated with heart attack is real," Anand says.
Anand and her team studied the effects of a healthy or unhealthy diet on more than 27,000 people, some of whom had the high-risk genes. They were of five ethnicities, including European, South Asian, Chinese, Latin American, and Arab.
The researchers drew from two different studies. One was called INTERHEART; the other was the FINRISK study, based in Finland.
In the INTERHEART study, the researchers compared 3,820 patients who had heart attacks with 4,294 who did not.
The Finnish study included 19,129 people. Of those, 1,014 had heart disease.
The studies used different dietary information. For the INTERHEART study, the researchers drew up a prudent diet score based mostly on raw vegetable and fruit intake. The score also took into account ''risk'' foods, such as fried foods, meat, and salty snacks.
For the Finnish study, diet information was collected from a questionnaire that included 130 food items. The score was based on intake of fruit, vegetables, and berries. Those who ate at least two out of those three foods daily earned the prudent rating.
The risk of heart attack for those with the bad genes who ate the least prudent diet was increased about 30%, Anand tells WebMD. "The risk [of heart attack] of those with the bad genotype who were in the high prudent diet group was not increased," she tells WebMD. This suggests that diet can weaken the effect of the genetic variation, the researchers say.
Healthy Diet and Heart Disease Risk: Perspective
The study findings suggest that lifestyle does matter, no matter what your genes have dealt you, says Eric Topol, MD, professor of translational genomics at The Scripps Research Institute and director of the Scripps Translational Science Institute in La Jolla, Calif.
He reviewed the study findings for WebMD.
"This suggests you may be able to do something about it [bad genes] if you follow a prudent diet that is rich in fruits and vegetables.
"I think this is a very sound report," he says. "It's really one of the first solid evidence of this whole field of nutrigenomics."
Nutrigenomics is defined as the way genes interact with nutrients.
The researchers found a dose response, Topol says. The worse the diet, the higher the risk of heart attack. The better the diet, the lower the risk.