Key Findings:
This study assessed whether ALA intake is associated with reducing fatal coronary heart disease (CHD) through decreasing fatal ventricular arrhythmias and sudden cardiac death (SCD). In this large, long-term (18 years), prospective cohort study of women, ALA intake was inversely associated with the risk of SCD but not with other types of fatal CHD or nonfatal MI. Every 0.1% increase in energy intake from ALA was associated with a 12% reduction in SCD risk. These results are very important as many women who die suddenly of a heart attack have no symptoms of heart disease. The authors suggest further study of diets and/or supplements enriched with ALA for antiarrhythmic properties and/or to reduce the risk of SCD as the benefits to public health would be significant.
ABSTRACT:
BACKGROUND: Alpha-linolenic acid, an intermediate-chain n-3 fatty acid found primarily in plants, may decrease the risk of fatal coronary heart disease (CHD) through a reduction in fatal ventricular arrhythmias and sudden cardiac death (SCD). METHODS AND RESULTS: We prospectively examined the association between dietary intake of alpha-linolenic acid assessed via updated food-frequency questionnaires and the risk of SCD, other fatal CHD, and nonfatal myocardial infarction (MI) among 76,763 women participating in the Nurses’ Health Study who were free from cancer and completed a dietary questionnaire at baseline in 1984. During 18 years of follow-up, we identified 206 SCDs, 641 other CHD deaths, and 1604 nonfatal MIs. After controlling for coronary risk factors and other fatty acids, including long-chain n-3 fatty acids, the intake of alpha-linolenic acid was inversely associated with the risk of SCD (P for trend, 0.02) but not with the risk of other fatal CHD or nonfatal MI. Compared with women in the lowest quintile of alpha-linolenic acid intake, those in the highest 2 quintiles had a 38% to 40% lower SCD risk. This inverse relation with SCD risk was linear and remained significant even among women with high intakes of long-chain n-3 fatty acids. CONCLUSIONS: These prospective data suggest that increasing dietary intake of alpha-linolenic acid may reduce the risk of SCD but not other types of fatal CHD or nonfatal MI in women. The specificity of the association between alpha-linolenic acid and SCD supports the hypothesis that these n-3 fatty acids may have antiarrhythmic properties. (Authors Abstract)