The National Institute for Health and Clinical Excellence (NICE) recommends that after a myocardial infarction patients should eat two to four portions of oily fish a week or omega 3 acid ethyl esters. The aim is 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.
What is interesting and rather startling is the meagre evidence upon which this far reaching decision is based.
The evidence is a large trial in Italy 10 years ago (GISSI) who found substantial reduction in fatal but not non-fatal heart attacks. These trials are massive enterprises requiring management skills of the highest. Asking simple questions with impeccable statistics and number of willing participants.
Questions remain, are the results reproducible, is fish oil equi-potent to eicosapentanenoic acid, docosahexaenoic acid, or the combination of both. Is surgical treatment better?
The chosen population is important, high or low incidence of myocardial heart disease.
Such research is needed not only because of the millions of people with heart disease worldwide, but also because the world’s marine fauna is being pushed towards extinction largely for commercial gain.
Since GISSI only one large trial has been published. The Japan Eicosapentanenoic Acid Lipid Intervention Study(UELIS) found that the addition of eicosapentanenoic acid reduced major coronary events by around a fifth. The trial demonstrated the benefit of eicosapentanenoic acid without docosahexaenoic acid and eicosapentanenoic acid in addition to effective lipid lowering treatment. The findings are striking because fish consumption in Japan is high.
In a systematic review Leon and colleagues assess the effects of fish oil on the secondary prevention of mortality and arrhythmias arrhythmias. No conclusive answer is available as no new evidence is available. It is amazing that one of the tenets of
believe is so fragile. Or is it?
Brunner and Iso 2009 Fish oil and secondary prevention of cardiovascular disease .BMJ vol 338 ppp 118-9
GSSI-Prevention Investigation 1999 Lancet vol 354, 447-55
Leon et al 2009 Effect of fish oil on arrhythmias and mortality: systematic review. BMJ . vol 337 pp 149-152
- Martin Eastwood