The National Institute for Health and Clinical Excellence recommends that after a myocardial infarction patients should eat two to four portions of oily fish a week. People who are not willing or able to do this may be prescribed omega 3 acid ethyl esters, which are licensed in the United Kingdom and Japan for patients who have had a myocardial infarction. The aim is to achieve a daily intake of 1 g of long chain polyunsaturated fish oil and thereby to reduce the risk of death or further non-fatal cardiovascular events.

In the NICE review, evidence for the benefit of purified fish oils in this patient group was provided by one large trial completed a decade ago.1 GISSI (Gruppo Italiano per la Sperimentazione della Streptochinasi nell’Infarto Miocardico) found substantial reductions in total mortality and mortality from cardiovascular disease but not in non-fatal cardiovascular events. Important questions remained. Were the findings reproducible? Is it eicosapentanenoic acid, docosahexaenoic acid, or the combination of both that protects against …