Fish oil is a source of omega-3 fatty acids in the diet. Your body needs omega-3 fatty acids for many functions, from muscle activity to cell growth. Omega-3 fatty acids come from food. They cannot be made in the body. Omega-3 fish oil contains both docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Omega-3 fatty acids are important nutrients that are important for the prevention and treatment of heart disease. Omegas and fish oil are good for lowering blood pressure, lowering triglycerides, slowing the build-up of plaque in the arteries, reducing the risk of abnormal heart rhythms, reducing the chance of heart attacks and strokes, and reducing the risk of sudden cardiac death in people with heart disease.