Fruity Heart Health

Fruit and veggies in diet can overcome genetic cardiac risks

18/10/2011 Toronto

A diet high in vegetables and fruits, especially those eaten raw or lightly cooked, can reduce the risk of having a heart attack or stroke -- even for those with at a genetic risk of cardiovascular disease. This according to a pair of studies at McMaster and McGill involving 27,000 subjects.

“Despite potentially having a family history of heart disease, or an implied genetic increased risk, you can actually turn off the bad genes by adopting healthy dietary patterns. ... this is important because sometimes people feel that their family history and their genes are not modifiable, so they just have to live with it, “says co-author Dr Sonia Anand, a professor of medicine and epidemiology at McMaster University.

Bad genes need help

The study, looked at those who carried the 9p21 variants -- long considered predictor for cardiovascular disease --and those who did in five ethnic groups: European, South Asian, Chinese, Latin American, and Arab. The findings showed that the risk of a heart attack in people with the 9p21 gene variant who consumed a “prudent diet” composed mainly of raw vegetables, fruits, and berries was similar to that of people without the high-risk gene variant. Those with the gene who lacked a healthy diet were twice as likely to have a heart attack.

Jamie Engert, a cardiovascular geneticist at McGill and joint principal investigator of the research says: “We know that 9p21 genetic variants increase the risk of heart disease for those who carry it, but it was a surprise to find that a healthy diet could significantly weaken its effect.” That reduced effect was seen in all ethnic groups except those of Arab ancestry, but that may have been due to the comparatively small number of participants in that group.

Dr Anand says it is not known how diet overcomes the power of DNA. “But we hypothesize that in some way a diet high in fruits and vegetables, and all of the good things that are contained in them, somehow modifies the expression of this particular gene. From the purely scientific perspective, it's interesting to see this interaction and do future studies to understand the mechanism, because everyone is always looking for drug targets or some way to modify the expression of genes.”

And that expression is powerful. Dr Beth Abramson, a cardiologist at St. Michael's Hospital in Toronto who was not involved in the research, notes that 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. She says: “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.”

Moreover eating a diet high in fruit and vegetables is good for everyone, says Dr Abramson, who is also a spokeswoman for the Heart and Stroke Foundation of Canada. In addition to the advice regarding fruit and vegetables – and she recommends 10 servings a day- her diet advice also includes keeping fat intake to a minimum.

Dr Anand acknowledges that in spite of the longstanding efforts of public health advocates to eat more fruit and vegetables, only a minority of the populace “takes this advice to heart.”

Dr Engert concurs but adds that as personal genomic testing becomes more affordable and common, those who learn they have this genetic propensity for cardiovascular disease may be motivated to adopt the diet and behaviour changes to lower their risk. “That doesn't mean that they won't get heart disease,” he says, explaining that there are likely multiple areas of DNA involved in boosting an individual's likelihood of having a heart attack or stroke. “It just means their increased risk because they carry this susceptibility gene is no longer there.”