When I was a kid my mom used to buy fresh fish for dinner regularly at the local fish monger. Then along came Captain Bird's Eye and a great campaign aimed at kids selling fish fingers/fish sticks. I can still hear the jingle in my head. Of course fish sticks were no where near as tasty or healthy as broiled fresh cod or skate but we kids begged, begged our mom for them. I kinda think the same thing is happening with the $1 billion dollar fish oil supplements industry. The "product" is sold as omega-3 fatty acids. A new analysis of existing data casts serious doubt on whether it protects against more heart problems in people with known heart disease. Whether it protects healthy adults against developing heart disease is a question as of yet without an answer but studies are on going and experts in the field are skeptical.
What I suggest is to eat fresh fish, broiled or steamed, never deep fried, at least twice a week. Not only does it taste great, it'll give you enough fish oil and help you minimise bad protein like red meat. If eating fish only did that, your heart would kiss you.