Another study, this time from Harvard University in the US, has demonstrated disappointing information about what is contained in the fish oil capsules taken by many people every day . The omega-3 content in many brands was a third less than advertised on the bottle and the other two thirds included significant saturated fats. The omega-3 fatty acids themselves were also generally oxidized, rendering them no longer effective. Little is known about the potential biological effects of the oxidized lipids. The authors proposed that the levels of saturated and oxidized fat may interfere with their intended biological/potential benefits, perhaps explaining research results demonstrating little or no effect on cardiovascular protection, reducing diabetes side-effects and studies on treatment foe ADHD in population studies. (


The research matched results from New Zealand ( published in, from October 2014: Fish oil supplements ) analyzing 30 different products, which also demonstrated over 80% had higher than acceptable levels of oxidation. Only 3 of the 32 supplements contained quantities of the supplements equal or higher than the labelled content, only 8% met the international recommendations for acceptable oxidation levels.


Most fish oil is farmed from ocean fish off the coast of Peru and Chile, they are processed onshore and then transported long distances again for more processing into capsules and packaging. Omega-3's are very unstable and breakdown easily in processing, becoming oxidized or rancid.


Fish oils are taken for a variety of reasons, particularly for the effects on reducing inflammation, improving immune function,  improving cognition and lowering cardiovascular disease risk. Recent studies show supplements may not be as helpful as previously thought in reducing heart attack or stroke. 


The authors' advice regarding reliable products was to regularly eat fresh oily fish, if you don't eat fish, you can get omega-3's from ground flax-seed or flax- seed oil, chia seeds, walnuts, canola oil and soy oil. The fats, vitamins, minerals, and supporting molecules in whole food rather than the solitary EPA and DHE omega-3 fatty acids may provide the health benefits demonstrated by studies of different populations with high and low omega-3 diets.  Also to note,  more omega-3's are being  manufactured from algal sources, an unoxidized source of omega-3 available as a supplement for those wishing to supplement their diets

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