One Fish, Two Fish

Compared with no (or very low) intake, modest dietary intake of fatty fish and omega 3 from seafood, the equivalent of one fatty fish meal a week, is associated with a marked 40% - 50% reduction in sudden cardiac death.  As such, some intake of omega 3 from seafood appears to be better than none.

Both clinical and animal experimental evidence suggests that the effect of omega 3 fish oils on the risk of sudden cardiac death relates primarily to reduced vulnerability to ventricular fibrillation, rather than to a reduction in atherosclerosis or non fatal myocardial infarction (heart attack).

Source: Circulation. 2003; 107:2632 The Fish Story: A diet hypothesis with clinical implications: n-3 polyunsaturated fatty acids, myocardial vulnerability and sudden death.