HEALTH NEWS

Study Title:

Fruits, Vegetables, and Weak Cardiovascular Genes

Study Abstract

Background
One of the most robust genetic associations for cardiovascular disease (CVD) is the Chromosome 9p21 region. However, the interaction of this locus with environmental factors has not been extensively explored. We investigated the association of 9p21 with myocardial infarction (MI) in individuals of different ethnicities, and tested for an interaction with environmental factors.

Methods and Findings
We genotyped four 9p21 SNPs in 8,114 individuals from the global INTERHEART study. All four variants were associated with MI, with odds ratios (ORs) of 1.18 to 1.20 (1.85×10−8≤p≤5.21×10−7). A significant interaction (p = 4.0×10−4) was observed between rs2383206 and a factor-analysis-derived “prudent” diet pattern score, for which a major component was raw vegetables. An effect of 9p21 on MI was observed in the group with a low prudent diet score (OR = 1.32, p = 6.82×10−7), but the effect was diminished in a step-wise fashion in the medium (OR = 1.17, p = 4.9×10−3) and high prudent diet scoring groups (OR = 1.02, p = 0.68) (p = 0.014 for difference). We also analyzed data from 19,129 individuals (including 1,014 incident cases of CVD) from the prospective FINRISK study, which used a closely related dietary variable. In this analysis, the 9p21 risk allele demonstrated a larger effect on CVD risk in the groups with diets low or average for fresh vegetables, fruits, and berries (hazard ratio [HR] = 1.22, p = 3.0×10−4, and HR = 1.35, p = 4.1×10−3, respectively) compared to the group with high consumption of these foods (HR = 0.96, p = 0.73) (p = 0.0011 for difference). The combination of the least prudent diet and two copies of the risk allele was associated with a 2-fold increase in risk for MI (OR = 1.98, p = 2.11×10−9) in the INTERHEART study and a 1.66-fold increase in risk for CVD in the FINRISK study (HR = 1.66, p = 0.0026).

Conclusions
The risk of MI and CVD conferred by Chromosome 9p21 SNPs appears to be modified by a prudent diet high in raw vegetables and fruits.

From press release:

A long-held mantra suggests that you can't change your family, the genes they pass on, or the effect of these genes. Now, an international team of scientists, led by researchers at McMaster and McGill universities, is attacking that belief.

The researchers discovered the gene that is the strongest marker for heart disease can actually be modified by generous amounts of fruit and raw vegetables. The results of their study are published in the current issue of the journal PLoS Medicine.

"We know that 9p21 genetic variants increase the risk of heart disease for those that carry it," said Dr. Jamie Engert, joint principal investigator of the study, who is a researcher in cardiovascular diseases at the Research Institute of the McGill University Health Centre (RI-MUHC) and associate member in the Department of Human Genetics at McGill University. "But it was a surprise to find that a healthy diet could significantly weaken its effect."

The research, which represents one of the largest gene-diet interaction studies ever conducted on cardiovascular disease, involved the analysis of more than 27,000 individuals from five ethnicities -- European, South Asian, Chinese, Latin American and Arab -- and the effect that their diets had on the effect of the 9p21 gene. The results suggest that individuals with the high risk genotype who consumed a prudent diet, composed mainly of raw vegetables, fruits and berries, had a similar risk of heart attack to those with the low risk genotype.

"We observed that the effect of a high-risk genotype can be mitigated by consuming a diet high in fruits and vegetables," said Sonia Anand, joint principal investigator of the study, and a researcher at the Population Health Research Institute and a professor of medicine and epidemiology at the Michael G. DeGroote School of Medicine at McMaster University. "Our results support the public health recommendation to consume more than five servings of fruits or vegetables as a way to promote good health."

"Our research suggests there may be an important interplay between genes and diet in cardiovascular disease," says the study's lead author Dr. Ron Do, who conducted this research as part of his PhD at McGill and is now based at the Center for Human Genetics Research at the Massachusetts General Hospital, Boston, Massachusetts. "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."

Study Information

Ron Do, Changchun Xie, Xiaohe Zhang, Satu Männistö, Kennet Harald, Shofiqul Islam, Swneke D. Bailey, Sumathy Rangarajan, Matthew J. McQueen, Rafael Diaz, Liu Lisheng, Xingyu Wang, Kaisa Silander, Leena Peltonen, Salim Yusuf, Veikko Salomaa, James C. Enge.
The Effect of Chromosome 9p21 Variants on Cardiovascular Disease May Be Modified by Dietary Intake: Evidence from a Case/Control and a Prospective Study.
PLoS Medicine
2011 October
Department of Human Genetics, McGill University, Montréal, Quebec, Canada.