Evidence first reported 20 years ago from the Greenland Inuit population suggested that fatty fish and fish oils contained substances that reduced the incidence of ischemic heart disease.

These substances, later determined to be omega-3 fatty acids, were found in early clinical trials to reduce platelet aggregation and to reduce hypertriglyceridemia by as much as 35%. More recent trials have found that omega-3 fatty acids also appear to reduce the risk of cardiac arrhythmia and sudden cardiac death and modestly reduce atherosclerotic plaque formation and hypertension.

Clinical trials have not demonstrated adverse effects at moderate daily doses. These findings have implications for clinicians who may want to suggest that patients increase their intake of fatty fish or supplement their diet with more concentrated sources of omega-3 fatty acids.