While we have known for some time about the potential benefits of fish in the diet, the specific role of supplements containing the beneficial component, omega-3 fatty acids, has been less clear, due to inconsistent results from various studies.
Fortunately, a new study released this month has clarified the link between supplementation with omega-3 fatty acids and the development of heart disease. This was actually a meta-analysis, meaning it summarized the data from multiple previous studies, in a manner that yields more information than the individual studies themselves. This was a very thorough analysis, specifically looking at the best quality studies (called randomized trials), and specifically looking at the useful component of omega-3 fatty acids, EPA and DHA. Moreover, the researchers were focused specifically on heart and circulatory complications.
What did they find? The intake of omega-3 fatty acids, either from food or supplements, reduced the risk of heart disease by 6%. This reduction is mild, and was actually insignificant, but there was a significant decrease specifically patients who started out with high triglyceride levels (> 150 mg/dL) or LDL cholesterol (> 130 mg/dL). When the researchers included additional nonrandomized studies, the reduction in heart disease was 18%. Another important conclusion was that there does not appear to be any harmful effect of supplementation.
So what can we conclude?
First, supplementation with 1 g of omega-3 fatty acids daily, either from food or supplements, appears to be mildly beneficial in preventing heart and circulatory disease.
Second, the majority of the benefit is in patients who start out with elevation of triglyceride or LDL cholesterol. Previous studies (such as this) have shown that otherwise healthy patients derive minimal or no benefit from fish oil supplementation.
Third, there does not appear to be evidence of harm at this level of supplementation.
Also of note, more detailed studies are ongoing to determine the optimal level of supplementation and specific patients. Finally, keep in mind that there are other potential benefits of fish oil supplementation unrelated to heart disease, so if supplementation makes you feel better or healthier, it may be reasonable. As always you should discuss your specific health situation with your doctor before considering any supplement or other therapy.
For more information, here as a video I recorded last year for the video blogging site Vidoyen.com, who asked me, Do Fish Oil supplements prevent heart disease? Here is a link to my 3 minute reply.
Reference to original article:
Alexander D, Miller P, Van Elswyk M, et al. A meta-analysis of randomized trials and prospective cohort studies of eicosapentaenoic and docosahexaenoic long chain omega-3 fatty acids and coronary heart disease risk. Mayo Clin Proc 2017;92:15-29