Fish oil, like the name implies, is oil extracted from the tissues of (oily) fish, namely among mackerel, herring and tuna. Cod liver oil, as the name also implies, is oil extracted from the liver of the cod fish. There is a similarity between fish oil and cod liver oil: they are both terrible for human consumption.
Even if one is cold-pressed, and the other is cold-pressed, extra virgin, they both quickly oxidize even in your stomach, generating destructive free radicals.
Omega 3 fatty acids being essential is a myth. The human body and brain does not need DHA or EPA from fish oil or cod liver oil. That too is a myth, and a dangerous one at that!
There are some parts of the human digestive system -specifically within the duodenum – that if you could touch it, it would burn you like fire. Ayurveda calls it “AGNI.” Fish oil comes from cold water creatures for the most part. Fish oil is too unstable for the AGNI process.
If you think you are getting a balanced source of vitamin A and vitamin D3 from cod liver oil, you are sadly mistaken. The cod liver oil of today is not the same cod liver oil your great grand-mother insisted upon. There are two main forms of vitamin A, retinol and beta carotene. The beta carotene is a pre-form which the liver has the control to convert into the necessary levels of vitamin A the body needs. Retinol is pure vitamin A without restrictions — your body can overdose on it. Our liver is designed to make retinol from carotenoids, found in beta carotene from food, and not absorb it purely from synthetic (or extracted oil) sources. Furthermore, retinol in cod liver oil competes with vitamin D3, reducing vitamin D3 effectiveness.
And furthermore, both fish oil and cod liver oil are capable of producing a disease that is rarely, if ever, talked about in the medical community: yellow fat disease (or pansteatitis.) This disease not only affects animals, such as felines, but also affects the liver of the human body. The liver of any animal, including cod fish liver is always a toxic, poisonous organ, and should be used sparingly.
I love fish, when they are alive. The unnecessary mass destruction of the marine ecosystem is now having a powerful effect on our climate. Some tsunami and earthquakes may be at the hands of human meddling!