Due to the way they’re processed, many fish oil supplements contain synthetic fish oil. DHA and EPA from fish oil are triglycerides, which are highly bioavailable. In most fish oil supplements, the DHA and EPA have been converted to ethyl esters — a synthetic substrate with low bioavailability that comes with health concerns.
A study, recently published in Annals of Internal Medicine on July 9 of 2019, examined the effectiveness of supplements and diets to prevent cardiovascular disease. The study looked at reviews and trials that encompasses 277 trials and 992,129 participants. They found that Omega-3 products yielded “low-certainty” evidence that they were associated with reduced risk for myocardial infarction and coronary heart disease.
One of the many problems with such medical studies is the products used. Some studies have highlighted this issue with fish oils.
Other studies looking into what common fish oil supplements actually contain have found that they have lower amounts of omega-3 than specified on the label, variable content and unregulated purity, and potentially significant levels of saturated fat and rancid oils.
Scientific American
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A recent article from Dr. Mercola’s site explains this issue in depth.
Whittel estimates about 98% of the omega-3 products on the market are inferior (and perhaps even toxic) due to the way the fish are caught and processed — a summary of which is provided in the graphic below.
In short, in order to render the rancid fish safe for human consumption, it must be cleaned, and what’s left at the end of this process is a synthetic ethyl ester omega-3 oil. The reason why some brands are able to provide you with higher concentrations of DHA, for example, is also because of this deconstruction and reconstruction process, and this appears to be part and parcel of Amarin’s complaint.
The processing most fish oils undergo transforms the omega-3 fats from their triglyceride form into an ethyl ester form. In fish, the DHA and EPA occur in the form of triglycerides, which are the most bioavailable. In most commercial fish oil supplements, however, the DHA and EPA are delivered in the form of ethyl esters.
Mercola recommends making sure your fish oil contains DHA and EPA in their triglyceride form. The company needs to process the fish oil the right way. Cold-pressed, minimally processed fish oil with triglyceride DHA and EPA is more expensive to produce.
We recommend Carlson and Nordic Naturals. Green Lifestyle Market carries Nordic Naturals fish oil.
Mercola also recommends krill oil, which has greater bioavailability.