What is cod liver oil and can it really help oil the joints?

Cod liver oil is a supplement that is derived from the liver of a cod fish and is a good source of the essential fat omega-3 which has a positive effect on everything from mental illness to the health of your heart. Certain advertisements give the impression that cod liver oil will literally oil your joints. While this isn't true, cod liver oil is very good for your joints. It contains anti-inflammatory substances called prostaglandins that have been proven to help those suffering from painful or swollen joints.  Cod liver oil is equally beneficial for your bones due to its high content of vitamin D.