Omega-3 fatty acids began making headlines in the 1970s when researchers studying the Greenland Inuit Tribe found that they were not as susceptible to cardiovascular disease as much as the general population. They attributed their heart health to the consumption of large amounts of fat from fish. Some initial studies found benefit from eating fish rich in omega-3 fatty acids. Based on this information, organizations such as the American Heart Association began encouraging individuals to consume omega-3 fatty acids from fish in order to boost heart health.
With the positive information coming out about fish oil, people began looking for other alternative ways to get the benefits of fatty fish without actually having to eat the fish. Fish oil supplements began gaining popularity. But do fish oil supplements really provide those heart protection benefits that we had originally thought? The answer is not as clear as one would hope.
Certain fish bulk up on omega-3 polyunsaturated fatty acids by consuming plankton and other plants. These fatty acids and their health benefits are then passed on to people who eat fish regularly. Omega-3 fatty acids, particularly EPA and DHA, are thought be beneficial to health by:
Evidence supporting the benefit of omega-3 fatty acids on heart health has been inconsistent. In 2006, researchers published a systematic review of studies in the journal BMJ that determined omega-3 fats do not have a clear effect on total mortality, combined cardiovascular events, or cancer. A 2008 study in the same journal looked at the literature regarding the effects of fish oil and determined that fish oil supplements do result in a small but significant reduction in deaths from cardiac causes, but had no effect on all-cause mortality.
A study done in 2009 found evidence that omega-3 fatty acids benefit people with heart failure. The large study, published in Lancet, looked at patients with chronic heart failure. It found that patients taking omega-3 fatty acids had fewer hospitalizations for cardiovascular reasons, fewer heart-related deaths, and lower overall death rates than those taking a placebo pill.
In 2009, a systematic review published in Clinical Cardiology concluded that supplements with EPA and DHA reduce the risk of cardiovascular events, cardiac death, and death from all causes in patients who already have heart disease.
In contrast, in 2012, two papers concluded that omega-3 supplements were not as beneficial as previously thought. Researchers who published the results of a randomized trial in the New England Journal of Medicine found that a prescribed drug containing EPA and DHA did not reduce mortality or the risk of cardiovascular events in people with diabetes or prediabetes who were at high risk for a cardiovascular events. In a systematic review of studies published in the Archives of Internal Medicine, researchers found that omega-3 supplements did not appear to decrease the risk of future cardiovascular events (eg, heart attack, heart failure, stroke, or death) in patients who already have cardiovascular disease.
Based on these conflicting results, there is no clear answer as to the benefits of taking omega-3 fatty acid supplements to prevent heart attacks, strokes, and early death in all people.
Eating fish, while not nearly as well studied as the supplements, has had more consistently positive results in observational studies. However, in the few randomized trials that have been done on the potential benefits of eating fatty fish in patients with heart disease, the results have been inconsistent. So even going to the source, whether it be salmon, tuna, mackerel, or some other oily fish, has not clearly lived up to the promises of good heart health.
Despite the inconsistent evidence, the American Heart Association (AHA) still recommends eating omega-3 fatty acids to promote heart health. According to the AHA, people should aim to eat two servings (8 ounces) of oily fish per week. These recommendations are not only based on the potential benefits of fish fat, but also on the idea that eating this type of fat will replace less healthy saturated fats found in other meats or in dairy products.
In addition, for people who have coronary artery disease, the AHA recommends about 1 gram of EPA and DHA per day. While it's best to get this from eating oily fish, the AHA encourages people to talk with their doctors about taking supplements. And those with high triglyceride levels may need an even higher amount of omega-3s.
Fish still probably has benefits for your overall health, so don't throw out your fishing pole! However, it is best to talk to your doctor before starting a supplement to be sure it is the right choice for you.
Academy of Nutrition and Dietetics
American Heart Association
Heart and Stroke Foundation of Canada
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Tavazzi L, Maggioni AP, Marchioli R, et al. Effect of n-3 polyunsaturated fatty acids in patients with chronic heart failure (the GISSI-HF trial): a randomised, double-blind, placebo-controlled trial. Lancet. 2008;372(9645):1223-1230.
Last reviewed July 2014 by Michael Woods, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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