Again, I ain't no doctor, but I can tell you what I myself take, and why. One is cod liver oil, the other is fish oil. The big difference is cod liver oil is high in vitamin D, which many people are deficient in, so this form may be a good one to take in the winter. Also, cod liver oil has vitamin A, an important nutrient, but one that can be toxic as high doses.
Carlson's lemon flavored cod liver oil is great because:
* No fishy burpsCONTAMINANT PROFILE: regularly tested using AOAC international protocols for potency and purity by an independent, FDA registered laboratory and found to be free of detectable levels of mercury, cadmium, lead, PCB's and 28 other contaminants.
* Easy to use
* Nitrogen-flushed bottle for freshness
* They use Norwegian cod, up there where it's less polluted
* The oil is separated from the liver tissues without the use of chemicals
* Glass, not plastic bottle
And Nordic Naturals Complete Omega 3-6-9 is great because:
* No fishy burpsCONTAMINANT PROFILE: (from company literature) Every batch of Nordic Naturals Omega-3 oils is tested for purity and freshness at NILU in Oslo, Norway. Our finished product is third-party tested by laboratories in the United States and in Canada, verifying purity and freshness levels.
* Capsules keep it fresh
* Borage oil to add gamma linoleic acid (great for PMS) (I wrote about growing borage here)
* From anchovies and sardines, fish low on foodchain and therefore less contaminated
* Uses rosemary extract (neat idea!) to preserve freshness.
* Obviously, Norwegian
NN DOES have a bit of soy; I have been told by the company that it's "fractionated" and therefore easy to digest. Just a tip.
NOTE: a recent report by ConsumberLabs, an independent supplement testing lab, showed that of all the fish oils they tested, things like mercury and PCBs weren't a huge problem, even with the cheapest brands (it may be because fish don't regularly store these things in their liver--it goes into the meat) BUT a few of them didn't have the level of Omega-3s they said they did and one was spoiled. As this is a pay-for-subscription service, I'll tell you that the one spoiled brand they found was Garden of Life.
Be careful of any fish oil that smells/tastes rancid and it goes bad very fast and then produces free radicals up the wazoo, which is very counterproductive if you're taking these things for your health! Use it up fast and keep it in the fridge, for starters!