Cardiovascular disease has long had the dubious distinction of being a leading cause of morbidity and mortality in Canada. Cardiovascular disease includes high blood pressure, excess levels of fat in the blood (high cholesterol and/or high triglycerides), narrowing of the arteries through either hardened vessel walls or plaque build up (atherosclerosis or arteriosclerosis), congestive heart failure (weakened heart muscle), and arrhythmias.
There are a number of lifestyle and dietary factors that have been associated with the development of heart disease, including smoking, high blood sugar, gender (men are more commonly affected than women, although rates in women increase dramatically after menopause), lack of exercise, a diet of predominantly refined and processed foods, inflammation, and various hormone imbalances.
But the good news is that cardiovascular disease is so prevalent that many nutrients, nutraceuticals, and lifestyle interventions have been studied for both the prevention and treatment of heart disease. One of the most widely studied supplements for cardiovascular health is essential fatty acids from fish oils.
Fish oils provide two key essential omega-3 fatty acids: EPA (eicosapentanoic acid) and DHA (docosahexanoic acid).
EPA is a key molecule for the production of anti-inflammatory compounds in the body, and inflammation has been implicated in the development of cardiovascular disease . As such it has been studied as a useful supplement in the prevention and/or treatment of atherosclerosis, arrhythmias, congestive heart failure, hypertension (high blood pressure), and high blood lipids. 
DHA is more specific for brain and nerve tissues. Fish oil has been shown to have anti-arrhythmic effects  and the mechanism may be related to the positive effect of DHA on the nerves that run through the heart to coordinate contractions of the various chambers.
Not all fish oil supplements are created equally. Considerations for choosing the best fish oil supplement come down to a few different factors.
1. Molecular distillation: The process of molecular distillation serves two purposes. Firstly, it is a key step in the removal of dioxins, PCBs, heavy metals, and other contaminants from the ocean. And secondly, it allows for concentration of EPA and DHA so that smaller doses of the supplement are able to contribute a greater effect to the body.
2. Emulsification: Since oil and water do not mix, the first stage of fat metabolism in the digestive tract is for bile from the liver to surround droplets of oil, essentially suspending them in the watery medium of digestive juices. Think of a creamy mayonnaise vs. vinaigrette: both contain oil and vinegar, but the emulsifying effect of the egg yolk in the mayonnaise allows the oil to be suspended in tiny, micro-droplets. Emulsification of oil improves absorption  as it supports the first step of fat digestion and eases the burden on the liver/gall bladder to provide sufficient bile. Many people complain of “fishy burps” from their supplements, which is generally a side effect of too much oil on too tired a liver. Emulsification eases the process. Those who have undergone gall bladder removal must be mindful of consuming fat but find emulsified oils to be well tolerated.
3. Sustainability: The planet that we inhabit is very different from that of our ancestors, or even our grandparents. Oceans are more polluted than ever, and fish stocks have been decimated in some areas. The health effects of fish oil in general make them so appealing that it can create internal conflict in some people when the environmental impact is considered. Non-profit, non-governmental organizations such as Friend of the Sea support marine health through certification of products that originate from sustainable fisheries and aquaculture. For more information, and to identify the logo, visit friendofthesea.org.
A fish oil supplement is a cornerstone of both prevention and treatment of heart disease in its many forms. A potent, pure, and high quality fish oil is a friend for life.
2. Gaby, A. Nutritional Medicine. Fritz-Perlberg publishing, 2011. 227-30, 247-8, 261-2, 289, 317, 329
3. Raatz SK1, Redmon JB, Wimmergren N, Donadio JV, Bibus DM. Enhanced absorption of n-3 fatty acids from emulsified compared with encapsulated fish oil. J Am Diet Assoc. 2009 Jun;109(6):1076-81. doi: 10.1016/j.jada.2009.03.006.