Raw Veggies Can Cut Heart Risk Despite Genes - MedPage Today
- Explain that diets high in raw vegetables and fruit appeared to reduce the risk of cardiovascular disease related to the chromosome 9p21 region, which has been identified as a genetic risk factor.
- Note that data on diet, cardiovascular outcomes, and genetics were derived from two large studies, INTERHEART (a retrospective study) and FINRISK (a prospective study), which did not use all of the same variables.
You can't choose your family or the genetic cardiovascular risk they pass on to you. But you can choose your diet -- and that may be enough to mitigate the deleterious effect of the genes, researchers reported.
Analysis of data from two large studies suggests that a "prudent" diet -- one rich in raw vegetables and fruit -- can markedly reduce the genetic risk of heart attack and cardiovascular disease, according to Jamie Engert, PhD, of McGill University in Montreal, and colleagues.
Several genetic studies have linked the chromosome 9p21 region with increased risk of heart attack and cardiovascular disease, but the interplay of genes and environment has not been clear, the researchers noted online in PLoS Medicine.
"We know that 9p21 genetic variants increase the risk of heart disease" for those who carry the risk alleles, Engert said in a statement. "But it was a surprise to find that a healthy diet could significantly weaken its effect."
To try to pin down the interaction of genes and environment, Engert and colleagues turned to an international retrospective case-control study of acute nonfatal MI, the INTERHEART study, as well as to a prospective study, dubbed FINRISK, of cardiovascular disease in Finland.
The researchers assessed the effect of four genetic variants previously linked to MI among 8,114 people who took part in the INTERHEART study, including 3,820 cases of heart disease and 4,294 of various ethnicities -- European, South Asian, Chinese, Latin American, and Arab.
They also analyzed the interaction of the genetic effect with three diet types, labeled:
- Oriental, including such items as soy sauce, tofu, pickled foods, green leafy vegetables, eggs, and low sugar
- Western, including eggs, meats, fried and salty foods, sugar, nuts, and desserts
- Prudent, including raw vegetables, fruits, green leafy vegetables, nuts, desserts, and dairy products
In FINRISK, the researchers assessed the effect of a single chromosome 9p21 genetic variant on incident cardiovascular disease, as well as the interaction with a "prudent" diet high in fresh vegetables and fruits and fresh or frozen berries or with diets with medium and low consumption of those foods.
The study had data on 19,129 people, including 1,014 incident cases of cardiovascular disease.
In INTERHEART, all four variants were associated with MI, with odds ratios ranging from 1.18 to 1.20 and with P values between 1.85x10-8 and 5.21x10-7.
They found a significant interaction between a prudent diet and all four of the variants. Specifically:
- The strongest interaction was with raw vegetable intake (all P<0.008), but adjusting for raw vegetables reduced the interaction to marginal significance while adjusting for other components of the prudent diet had little effect.
- One variant, dubbed rs2383206, was strongly associated with heart attack in the group with the lowest prudent diet score (OR 1.32, 95% CI 1.18 to 1.48, P=6.82x10-7).
- The effect was diminished step-wise for the medium and high scoring prudent diet groups with odds ratios of 1.17 and 1.023, respectively, but only the first represented a significant increase in risk.
In FINRISK, a diet high in vegetables, fruits, and berries was inversely associated with cardiovascular disease (HR 0.79, 95% CI 0.66 to 0.94) compared with the diet lowest in those foods. The effect was significant at P=0.0076.
As in INTERHEART, the chromosome 9p21 variant showed an effect of the risk allele on incident cardiovascular disease among individuals with low and medium consumption of vegetables, fruits, and berries, but demonstrated no effect in the high consumption group. The hazard ratios were 1.22, 1.35, and 0.96, respectively, but only the first two were significant, at P=3x10-4 and P=4.1x10-3.
The researchers cautioned that the findings might be affected by recall bias in the INTERHEART study, because participants may not have accurately remembered and reported their diets.
Also, they noted, there was only a small number of incident cases of cardiovascular disease in the FINRISK study, which might have limited the power of the analysis.
The two studies used different definitions of cardiovascular disease and different dietary variables, which may have complicated comparisons between study populations.
The study had support from the Heart and Stroke Foundation of Ontario.
The authors declared that there are no competing interests.
From the American Heart Association:
15 Oct, 2011--
Source: http://news.google.com/news/url?sa=t&fd=R&usg=AFQjCNHpQJ6Zj4AmMSYr8z3i9DtUOn8dlw&url=http://www.medpagetoday.com/Cardiology/Prevention/29048
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