Much evidence shows that the marine omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid have beneficial effects in various cardiac disorders, and their use is recommended in guidelines for management of patients after myocardial infarction. Questions have been raised about their usefulness alongside optimum medical therapies with agents proven to reduce risk of cardiac events in high-risk patients. Additionally, there is some evidence for a possible pro-arrhythmic effect in subsets of cardiac patients. Some uncertainly exists about the optimum dose needed to obtain beneficial effects and the relative merit of dietary intake of omega-3 polyunsaturated fatty acids versus supplements. This review looks at the evidence for the effects of omega-3 polyunsaturated fatty acids on various cardiac disorders and the risk factors for cardiac disease.
Dietary intake of fish is the best way to increase marine n-3 PFA intake. 1 gram per day of omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic supplement is equivalent to 55-85 g of fresh tuna, sardine, salmon or trot or 650 g Atalntic cod.
The amount of PUFA intake to educe triglycerides cannot be achieved by diet alone.
Marine n-3 PUFAs act as pleiotropic agents on the cardiovascular system with a diverse range of effects, most of which are beneficial. So far, the most important effect seems to be related to reduction in mortality after a myocardial infarction. Although findings from several studies have suggested the possibility of an anti¬arrhythmic effect, other clinical studies have not convincingly supported this mode of action. The overall effect of n-3 PUFAs in patients with coronary ischaemia without previous myocardial infarction is not established, with a potential benefit in the reduction of ischaemic coronary events set against an ongoing controversy over a possible rise in the risk of arrhythmic events. The anti-¬inflammatory, anti-atherosclerotic, and anti-immuno¬modulatory effects have not yet been proven to give clinical benefits.
Saravanan et al 2010 , Cardiovascular effects of marine omega- 3 fatty acids . The Lancet vol 376 pp 540-550
- Martin Eastwood