Omega-3 fatty acids or PUFA are considered essential fatty acids because these are not made in the body or are inefficiently converted from ALA to EPA and DHA. Thus, we need to get them from our diet .
Omega-3 fatty acids reduce the risk of arrhythmias, decrease the triglyceride levels, slow the growth of the atherosclerosis and marginally reduce the blood pressure -by reducing the inflammation and lowering the clotting risk. They also play a beneficial role in dementia, depression, arthritis and certain cancers.
Experts usually recommend 1 gram of DHA and EPA combined from fish oil daily for those with heart disease. People with high levels of triglycerides may take doses of up to 4 grams a day under the supervision of a physician. There is an increased tendency of bleeding in people taking high doses and especially those who are on anti platelet drugs and anti coagulants.
However, the recent randomized trials
in high-risk populations (those with either multiple risk factors or a history of cardiovascular disease) have suggested very little benefit from omega-3 fatty acids.
Patients with multiple cardiovascular risk factors were given 1 gram of fish oil per day vs placebo, and it showed no benefit. Also, other meta-analyses have been published in the past year that looked at all of the randomized trials in aggregate. These are secondary-prevention, randomized trials with high-risk populations. In general, these meta-analyses have shown disappointing results.
It is very important to keep in mind that these high-risk populations -- include many individuals who are already taking multiple heart medications such as statins, aspirin, and ACE inhibitors, which may obscure the effect of omega-3 fatty acids. There may be very little incremental benefit from omega-3 fatty acids in that setting.
First, these randomized trials of fish oil do not advise against the recommendation to have at least 2 servings of dietary fish per week. That is a recommendation from the American Heart Association and many other professional societies, and many studies suggest benefit. Some of the benefit may be because dietary fish is replacing other foods that could increase risk, such as red meat or foods high in saturated fat.
Second, in patients who are candidates for prescription omega-3 fatty acids, especially those who have very high triglyceride levels, these findings do not cast a doubt on that indication for use. That would still be an appropriate use. In patients who are taking fish oil and are doing very well on it and feel strongly that the fish oil is helping their symptoms or are a benefit to them, there is no strong basis from these studies for encouraging them to stop, because there were no major risks associated with fish oil found in the studies.
To sum it all up. Omega-3 fatty acids are not needed nor recommended for primary or secondary prevention of cardiovascular-related mortality and morbidity. However if the patient is using it and is tolerating it, it can be continued.
But, in those people whose triglycerides are very high, these may still be a good recommendation.