By now everyone has heard the benefits of taking omega 3 fish oils for health, and that is definitely a good thing. However, with everything there can be a down side, even something as good as omega 3 fish oils.
A recent research article published in Food Chem Toxicol. 2010 Nov;48(11):3093-7. Epub 2010 Aug 6 provided data that indicates that we need to be aware of something called 'POPs'. That would be Persistent Organic Pollutants, or POPs.
What are these POPs? Things like PCBs (polychlorinated biphenyls), nasty little compounds, and aryl hydrocarbon receptor agonist compounds. None of which is beneficial to us humans.
One of the most pointed pieces of info in the article was the defining amounts of these compounds in various sources of the omega 3s. Doctor's Nutrition has always been aware of these compounds and have done everything in our power to make sure they are not in our products. The research provided info that one of the highest concentrations of these unwanted compounds was in salmon and tuna oil. Obviously these big fish are higher up the food chain and have more time for concentration of the unwanted pollutants. PCBs ranged from <0.8 to 793 ng g(-1) oil, with salmon- and seal-derived products yielding the highest values.
So where do we get our fish oil? From anchovies, one of the smallest species of fatty fish. Even starting there we make sure it has undergone molecular distillation and is tested to be the lowest possible in all contaminants. We have always discouraged the use of salmon and 'bigger' fish oils. Now you know why!