Fish Oil
Fish oils come from fatty or oily fish, such as trout, mackerel, tuna, herring, sardines, and salmon. They contain omega-3 fatty acids, and many contain vitamins A and D.
The benefits of fish oil seem to come from its omega-3 fatty acid content. Fish that are especially rich in these oils include mackerel, herring, tuna, and salmon. The body doesn't produce many of its own omega-3 fatty acids. Omega-3 fatty acids reduce pain and swelling, and also prevent the blood from clotting easily.