BOSTON, MASSACHUSETTS. There is significant evidence that a moderate to high fish intake protects against sudden cardiac death or fatal coronary heart disease. There is also evidence that supplementation with fish oil (EPA and DHA) can reduce coronary death among patients who have survived a heart attack (myocardial infarction). Now researchers at the Harvard Medical School report that women with a high blood plasma level of DPA, EPA and DHA (docosapentaenoic acid, eicosapentaenoic acid and docosahexaenoic acid, respectfully) have a substantially reduced risk of suffering a non-fatal heart attack.
The study involved 32,826 nurses (average age of 60 years) who had blood samples drawn in 1989 or 1990. During a 6-year follow-up, 147 non-fatal heart attacks occurred in the group (0.07%/person year). The 147 heart attack (MI) patients were matched with 288 controls and the fatty acid content of their plasma and red blood cells (erythrocytes) measured. The researchers observed that the average plasma concentrations of DPA, EPA and DHA were significantly lower in MI patients than in controls. They conclude that the nurses in the highest quartile of EPA plasma level have a 77% lower risk of suffering a non-fatal MI (myocardial infarction) than do those in the lowest quartiles (after adjusting for confounding variables). Corresponding risk reductions for DPA and DHA were 60% and 54% (not statistically significant). The association between fatty acid levels in erythrocytes and MI risk was statistically non-significant. Similarly, there was no statistically significant correlation between high plasma levels of alpha-linolenic acid (ALA) and a lower risk of non-fatal MI.
The researchers also noted that high plasma concentrations of EPA and DPA and, to a lesser extent, DHA were associated with more favorable levels of triglycerides, HDL cholesterol, and several inflammatory markers. They conclude that higher plasma levels of EPA and DPA are associated with a lower risk of non-fatal heart attacks (MI) among American women.
Sun, Q, et al. Blood concentrations of individual long-chain n-3 fatty acids and risk of nonfatal myocardial infarction. American Journal of Clinical Nutrition, Vol. 88, 2008, pp. 216-23