Fish is good food, certainly, but let's not go overboard. Here are the fish facts. While population studies look at fish consumption, clinical studies almost always use fish oil capsules. It's generally assumed that the supplements provide the same health benefits as the fish itself. However, there may be other beneficial compounds in the fish not found in the capsules.
Fatty fish are the richest sources.
Like aspirin, these omega-3s make platelets in the blood less likely to stick together and may reduce inflammatory processes in blood vessels. Thus they reduce blood clotting, thereby lessening the chance of a heart attack. But the same would happen if you replaced the meat with beans or other foods low in saturated fat. Thus, when researchers control for saturated fat intake, the effect of fish on cholesterol often turns out to be minimal, at best. Large amounts of fish oil are known to reduce triglycerides, the major type of fat that circulates in the blood.