It has been observed that the fish eating populations (e.g. eskimos) rarely suffer from heart diseases. Now it has been proven that fish and fish based oils play a protective role in heart diseases. This protective quality has been ascribed to long-chain n-3 PUFA. These fatty acids decrease fibrinogen levels, inhibit the activity of platelets and also the clotting process. Moreover, they reduce the levels of Cholesterol and triglycerides.
Generally, 100-200 gm of fish taken twice a week can play a preventive role with regard to heart disorders.