In a new study a team of researchers looked at the genotypes of 27,243 people from two separate studies to see if they had a certain gene variant. Earlier studies including a 2010 meta-analysis in the Journal of the American Medical Assn. found that the 9p21 gene is associated with a higher risk of heart attack and cardiovascular disease.
Despite the genetic makeup, people may be able to do something about it say researchers. The participants in this study represented a number of ethnicities: South Asian, Latin American, Arab, Chinese and European. They were asked about their dietary habits, including how many raw fruits and vegetables they ate, and how often.
Among the participants, those who had the high-risk genotype and ate a diet low in raw vegetables and fruits had a higher risk of heart attack or cardiovascular disease. However, eating a diet high in vegetables and fruits seemed to have a protective effect -- that group had a heart attack risk that was comparable to people with a low-risk genotype.
The study was published this week in the journal PLoS Medicine.
“Our research suggests there may be an important interplay between genes and diet in cardiovascular disease,” said lead author Ron Do, in a news release. “We found that in people with this high-risk gene who consumed a diet rich in vegetables and fruits, their risk came down to that of people who don't have that gene,” said Dr. Sonia Anand, a lead author and professor of medicine and epidemiology at the Michael G. DeGroote School of Medicine at McMaster University. “Despite having a high genetic risk for heart disease, a healthy lifestyle can actually turn off the gene,” said Anand. She also said it's not yet clear exactly how diet affects the gene.
Experts not involved in the Canadian research say the research provides more evidence that there is a strong gene-environment interaction involved in heart disease and other conditions.
“This may be true for other issues. There may be genetic factors that make a patient more sensitive to salt and develop hypertension, whereas another person can eat large amounts of salt and maintain normal pressure,” said Dr. Carl Lavie, medical director of Cardiac Rehabilitation and Prevention at the John Ochsner Heart and Vascular Institute at Ochsner Health System in New Orleans. “Other studies have also shown that those who eat healthier diets tend to offset the risk that same chromosome places on them,” said Dr. Phil Ragno, director of cardiovascular health and wellness at Winthrop University Hospital in Mineola, N.Y.
Dr. Beth Abramson, a cardiologist at St. Michael's Hospital in Toronto who was not involved in the research, said people with a close family relative who experienced early heart disease, such as a parent or sibling, have double the risk of having a heart attack or other cardiovascular event as those in the general population. “What this study seems to imply is that you shouldn't throw in the towel if you have a family history or are at risk for heart disease because healthy living with a healthy diet, in addition to other lifestyle changes such as exercise and maintaining a healthy body weight, can take away from the risk that genes give you,” she said.
“We know that despite public health recommendations to eat five or more servings of fruits and vegetables a day, only a minority of people take the advice seriously,” said Anand. “Genetic information may be a motivation to help people take the public health recommendation seriously.”
But she added that this research doesn't mean that people should go out and get genetically screened for the presence of 9p21 variants. Screening is costly and not routinely done. “This points the way toward the future and where we're going in terms of understanding the genetics of heart disease,” said Dr. William O'Neill, cardiology professor and executive dean of clinical affairs at the University of Miami's Miller School of Medicine. “Maybe in the next few years, we may be able to do specific gene scans on individual patients and if we find the patients who have genetic high risk, we really want to concentrate on modifying risk by targeting smoking, cholesterol and diet.”
“We often think of genetic factors as being un-modifiable factors,” said Anand. “But lifestyle factors can actually change the genes.” Dr. Ron Do, who was part of the study while at McGill University added, “Future research is necessary to understand the mechanism of this interaction, which will shed light on the underlying metabolic processes that the 9p21 gene is involved in.”
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