Fish Oil and the Heart

Three new studies add strongly to the growing evidence that consumption of fish and fish oil supplements can reduce death from heart disease.
In the April 10 issue of the Journal of the American Medical Association, investigators from the Harvard School of Public Health reported that women who consumed more fish and fish oil (omega-3 fatty acids) significantly reduced their risk of heart disease. In this study, among 85,000 women enrolled in the Nurses' Health Study, those who ate fish 2 to 4 times per week reduced their risk of heart disease by 30%, compared to women who rarely ate fish.
Similarly, in a study published in the April 11 issue of the New England Journal of Medicine, investigators from Massachusetts General Hospital reported that men in the Physicians' Health Study (men who had no evidence of prior heart disease) who consumed omega-3 fatty acids had a significantly reduced risk of sudden death.
And finally, investigators from Italy reported this week in Circulation that consuming 1 gram per day of omega-3 fatty acid supplements resulted in a significantly reduced risk of sudden death among survivors of heart attacks.
While a major benefit of fish oil in these studies appears to be a reduction in sudden death from cardiac arrhythmias, omega-3 fatty acids also appear to reduce triglyceride levels, reduce blood pressure, and stabilize the blood clotting mechanisms. Thus, there are several pathways in which fish oil can potentially benefit the cardiovascular system. The evidence that omega-3 fatty acids benefits the heart, thanks to these three studies, is now nearly irrefutable, and will no doubt become widely accepted by the medical community. (The American Heart Association, however, is waiting for yet more evidence before changing its official recommendations.)
Omega-3 fatty acids are most plentiful in darker, fatty fish such as mackerel, sardines, and salmon. If individuals take the new evidence regarding fish oil to "heart," we are very likely to see a shortage of affordable sources. (People might also want to keep in mind that there is some concern about the level of mercury in certain fish. The FDA last year said that pregnant women should not eat some kinds of fish - king mackerel being one of them - because of the risk of mercury toxicity to the fetus.) Fortunately, scientists are avidly attempting to devise a means of synthesizing omega-3 fatty acids so that we are not completely reliant on marine vertebrates.