Dietary Alpha-linolenic Acid intake & risk of sudden cardiac death & coronary heart disease.
Dietary Alpha-linolenic Acid intake & risk of sudden cardiac death & coronary heart disease.
Year: 2005
Authors: C M Albert, K Oh, W Whang, J E Manson, C E Chau, M Stampfer, W Willett, F B Hu.
Publication Name: Circulation.
Publication Details: Volume 112; Page 3232.
Abstract:
It is well established that long chain n-3 fatty acids derived from fish are associated with reduced risks of coronary heart disease (CHD), particularly mortality from CHD and sudden cardiac death (SCD). Because fatty fish is not readily available or nor palatable to many people, the cardio-protective effects of alternative sources of n-3 fatty acids, such as alpha-linolenic acid (ALA), are currently being investigated. ALA is an intermediate-chain fatty acid found in high concentrations in flaxseed, canola, and soybean oils. Previous prospective cohort studies have demonstrated an inverse association between ALA intake and risk of fatal CHD with no – or little effect – on nonfatal myocardial infarction (MI). The objective of this study was to specifically examine the relationship between ALA intake and risk of SCD, while also reporting on the association between ALA intake and other coronary death and nonfatal MI during 18-years of follow-up. Data for the study was obtained from the Nurse’s Health Study, a prospective cohort study that consisted of 76,763 women. All participants were free from cancer and completed a semi-quantitative food frequency questionnaire (FFQ) at baseline in 1984. FFQ’s were also completed in 1986, 1990, 1994, and 1998. Dietary ALA intake was calculated based on total ALA intake from values reported in the US Department of Agriculture database. ALA was found to be the predominant n-3 fatty acid consumed, with intake ranging from 0.37% of total energy intake in the lowest quintile, to 0.74% of energy in the highest quintile. During 18-years of follow-up, 206 cases of SCD, 641 other CHD deaths, and 1604 nonfatal MI cases were reported. While controlling for coronary risk factors, and other fatty acid intake (including long-chain n-3 intake), intake of ALA was found to be inversely associated with risk of SCD, but not with risk of other fatal CHD or nonfatal MI. Women in highest two quintiles of ALA intake were found to have a 38% – 40% lower risk of SCD compared to women in the lowest quintile of ALA intake. When examined continuously, every 0.1% increase in ALA intake (as percent of energy) was associated with a 12% reduction in SCD risk. The observed inverse relationship between ALA intake and SCD remained significant in women with high intakes of long chain n3 fatty acids. These data further support the hypothesis that ALA may influence cardiovascular risk through effects on fatal ventricular arrhythmias. Other plausible mechanisms by which ALA may exert favorable effects on coronary and SCD risk include endothelial function, inflammation, and thrombosis. Based on the growing body of evidence demonstrating the beneficial effect of diets enriched with ALA on SCD, these researchers state that the public health impact of such a low cost and easily accessible intervention could be significant.
