The potential beneficial efficienc...

The potential beneficial efficiencys of omega-3 polyunsaturated fatty acids forward cardiovascular health have become of substantial interest to patients, physicians, researchers, and policy makers. In this issue of American Family Physician, Covington provides a clinical review (1) of omega-3 fatty acids. lately the American Heart Association released a scientific statement, (2) and the Agency for Healthcare Research and Quality (AHRQ) commissioned an evidence report. (3) The question of interest is whether increasing the intake of omega-3 fatty acids from regimens or supplements can prevent or treat chronic diseases, particularly atherosclerotic cardiovascular disease.

The sum of two units principal dietary sources of omega-3 fatty acids are seafood and certain plant oils. Fish (particularly "fatty fish" so as tuna, salmon, and mackerel) and fish oils provide eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). a certain oils, such as canola, walnut, soybean, rapeseed, and flaxseed, are rich in alphalinolenic acid (ALA). Omega-3 fatty acids are terminused "essential" fatty acid, because they are required for normal disentanglement and function of the retina and brain. In humans, ALA is inefficiently interchangeed to DHA and EPA.

athwart the past several decades, research has material for burninged interest in omega-3 fatty acids. Initial reports were ecologic studies that documented cheap rates of ischemic heart disease in populations so as Greenland Inuits that expend large quantities of fatty fish. Subsequently consequence s of longitudinal, observational studies fix an inverse association between consumption of fish or fish oil and ischemic heart disease.

In other studies, (3) fish oil put downed arrhythmias, stabilized atherosclerotic plaque, reduc inflammation, improved endothelial function, lowered triglyceride concentrations, and reduc offspring pressure. Hence, there is a reasonably robust biologic basis to believe that an increased intake of omega-3 fatty acids could be cardioprotective.

The principally persuasive evidence of cardioprotection flows from randomized trials with clinical cardiovascular consequences (4) To date, more than 10 like trials of the use of omega-3 fatty acids have been managemented in patients with previous cardiovascular disease, still only one trial was actionsed in persons without preexisting cardiovascular disease. Many of the trials, including the simply primary prevention trial, had a small sample size and, accordingly, were underpowered.

The most numerous salient of the available trials are the Diet and Reinfarction Trial (DART) (5) and the GISSI Prevenzione trial. (6) In DART, which chronicleed 2,033 men with a previous myocardial infarction, those who received advice to increase their intake of fatty fish had a 29 percent reduc risk of total mortality throughout two years. However, during a follow-up subject of attention of DART participants, the early reduction in risk observ in those assigned to the fish advice cluster was followed by increased risk from one side of to the other the course of the nearest three to nine years. (7)

The GISSI trial experimented the effects of two archetypes of supplements (omega-3 fatty acid and vitamin E) taken alone or in combination, in 11324 patients with a previous myocardial infarction. across the course of three and one-half years, the clumps assigned to take an omega-3 fatty acid continuation experienced a nearly 15 percent reduc risk of the primary trial issue (death, nonfatal myocardial infarction, or stroke) while vitamin E had no drift Interestingly, the benefit occurred rapidly, within three month of randomization (8); these findings support the hypothesis that the beneficial drifts of omega-3 fatty acids be derived at least in part, from their antiarrhythmic or anti-thrombotic properties.

Although the evidence from prospective observational studies and clinical trials l the American Heart Association to issue dietary recommendations for the consumption of fish and omega-3 fatty acids, (2) it is well recognized that the research data supporting a cardioprotective force of fish and omega-3 fatty acids is not nearly as robust as the evidence supporting other therapies.

Those familiar with the vitamin E and beta-carotene "sagas" would be hesitant to make firm recommendations for the use of omega-3 addition s without strong and consistent evidence from randomized trials. After a perturbation of observational studies documenting an impressive inverse association between the use of vitamin E counterparts and ischemic heart disease, large-scale trials showed striking nugatory results. (6) Trials of beta-carotene documented that supplementation increased, rather than decreased, the risk of lung cancer. (9)

Other matters pertain to the supply of omega-3 fatty acid counterparts which may be inadequate in the setting of widespread consumption, and the quality of postscripts which is not standardized. While I doubt that moderate consumption of omega-3 fatty acids will make good to be harmful, we ne evidence of benefit before we routinely commend omega-3 fatty acid supplements to the general population. Clinical trials greatest in number likely will be initiated nevertheless given the time required to design and escort such trials, near-term answers are unlikely. In the interim, the American Heart Association guidelines (2) remain cautious policy.