17 October 2011
ByAppeared in BioNews 629
Eating high quantities of fresh fruit and vegetables can counterbalance the effects of having a genetic predisposition to heart disease, an international study has found.
The research, led by scientists at McGill University and McMaster University, Canada, examined the incidence of heart attack (myocardial infarction) in individuals carrying four different high-risk variants of a region of DNA called 9p21. They then investigated how the risk was influenced by environmental factors such as smoking, physical activity and diet. They found that having a diet high in raw vegetables and fruit reduced the likelihood of heart attack in people who carried any one of the high-risk genetic variants.
Strikingly, for one of the genetic variants, rs2383206, the extra risk could be completely abolished by a vegetable-heavy diet. Carriers of rs2383206 who ate plenty of fruit and vegetables were no more likely to have a heart attack than individuals who did not carry any of the four high-risk genetic variants. Professor Sonia Anand, who led the team at McMaster University, commented: 'Our results support the public health recommendation to consume more than five servings of fruits or vegetables as a way to promote good health'.
The study had 8,114 participants from five ethnic groups (3,820 heart attack patients and 4,294 controls), selected from people enrolled in a huge global study on heart attack called INTERHEART. By examining participants' DNA, the researchers re-confirmed the increased risk of heart attack in carriers of any of the four genetic variants. Questionnaires were used to examine diet, smoking and physical activity. The team acknowledge that a limitation of the study is that self-reporting of lifestyle factors in this way can be prone to bias.
To support their findings, the researchers also analysed data from another large study into cardiovascular disease (CVD), the FINRISK study. This examined 19,129 Finnish individuals, including 1,014 cases of CVD, and found a similar relationship between genetic predisposition, diet and risk of CVD. However, this study looked at the prevalence of a different high-risk variant of 9p21; used a different questionnaire to investigate diet; and looked at CVD in general (of which heart attack is just one disorder). The two studies cannot, therefore be directly compared.
Judy O'Sullivan, senior cardiac nurse at the British Heart Foundation, said: 'This piece of research is certainly an interesting and useful insight into how our risk of developing heart disease is influenced by a number of factors. [...] The relationship between [lifestyle and genetics] is often very complicated and we don't yet have all the answers but the message appears to be very simple; eating lots of fruit and vegetables is great news for our heart health'.