SOUTHAMPTON, UNITED KINGDOM. It is well established that populations with a high consumption of oily fish have a lower incidence of heart disease and several studies have confirmed that fish oils (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) are the protective components. There is also impressive evidence that they help prevent atherosclerosis, lower blood pressure, reduce triglyceride levels, and are highly protective against both fatal and non-fatal heart attacks. Fish oils also have antiarrhythmic effects and help prevent blood clotting.
Recent research concludes that perhaps the most important effect of oils from fish, when it comes to preventing cardiovascular disease, is their ability to stabilize atherosclerotic plaque by reducing the infiltration of inflammatory and immune cells (lymphocytes and macrophages) into the plaque. Heart attacks are now believed to involve the rupture of an atherosclerotic plaque. These plaques come in two main varieties, those with a thin, unstable fibrous cap and those with a thick, stable fibrous cap. A recent study showed that supplementation with 1.4 grams/day of fish oil significantly reduced macrophage infiltration and resulted in a substantial shift towards a preponderance of stable, thick-capped plaques. At least two studies have shown that the beneficial effects of fish oils on heart health become clear after about 2 months.
Calder, Philip C. New evidence in support of the cardiovascular benefit of long-chain n-3 fatty acids. Italian Heart Journal, Vol. 4, July 2003, pp. 427-29