n-3 fatty acids and cardiovascular disease.
n-3 fatty acids and cardiovascular disease.
Year: 2006
Authors: Breslow, JL
Publication Name: Am. J. Clin. Nutr.
Publication Details: Volume 83, Page 1477S.
Abstract:
Almost 30 years ago, studies began to suggest that ingestion of omega 3’s provides protection against CVD. Of 14 prospective cohort studies (studies that look at lifestyle risks) of omega 3’s and CVD, omega 3’s were found to be beneficial in twelve and to have no effect in only two. The association between increasing intakes of EPA and DHA and reductions in the relative risk of death from CVD has been established in a number of studies. Men who had recovered from myocardial infarction and advised to eat fatty fish had a significant 29% reduction in 2-year all-cause mortality (death due to many factors) compared with men who received no diet advice. The investigators concluded that “a modest intake of fatty fish (2 or 3 portions per week) may reduce mortality in men who have recovered from myocardial infarction.” This corresponds to an additional 500–800 mg/day of n-3 fatty acids as EPA plus DHA. In the group randomly assigned to increase its intake of oily fish, a subgroup chose to ingest a fish oil capsule containing 450 mg of EPA plus DHA daily. In this subgroup, total mortality was lowered by 56% and coronary heart disease mortality was lowered by 62%, which strongly suggests that the benefit of fish consumption was in the fish oil fraction. A number of studies have shown beneficial effects of ALA on heart health. For example, in the Health Professionals Follow-up Study a 1% increase in ALA intake (expressed as percent of energy) was associated with a 40% reduction in the risk of non-fatal coronary heart disease (CHD). Another major study, the Lyon Diet Heart Study, included participants who had previously survived a myocardial infarction. The experimental group consumed a typical Mediterranean style diet rich in ALA, whereas the control group consumed a typical Western-type diet low in ALA. Those who consumed the diet rich in ALA had a 75% reduction in non-fatal heart attacks, and a 70% reduction in total death compared to the control group. ALA, EPA and DHA may protect the heart through improvements in abnormal heart rhythms and a reduction of blood platelet stickiness (thrombosis). More recently, studies have shown that omega 3 fatty acids lower C-reactive protein (CRP)?an inflammatory compound produced in the body. Many international health organizations have established recommended dietary intakes of n3 fatty acids. In 2002 the American Heart association established the following recommendations: 1) Individuals without documented coronary heart disease were advised to eat fish (preferably oily) twice per week plus oils and foods rich in ALA (flaxseed, canola, soy, walnuts). This equates to approximately 500mg/d of n3 fatty acids compared with current intakes of < 100mg/d. 2) Individuals with documented coronary heart disease were counseled to consume 1 g/d of EPA+DHA from oil fish and/or in supplement form. 3) Individuals with hypertriglyceridemia could ingest 2-4 g/d of EPA+DHA under a physicians care. In conclusion, directions for future research in the area of omega 3 fatty acids should include: 1) more randomized controlled trials (RTCs); 2) investigating the impact of EPA and DHA separately versus together, which has been the case in the majority of studies to date; and 3) investigating the effect of ALA versus EPA + DHA on various endpoints of CVD.
