Cardiovascular disease Edit
Evidence, in the population generally, does not support a beneficial role for omega-3 fatty acid supplementation in preventing cardiovascular disease (including myocardial infarction and sudden cardiac death) or stroke.[3][19][20] However, omega-3 fatty acid supplementation greater than one gram daily for at least a year may be protective against cardiac death, sudden death, and myocardial infarction in people who have a history of cardiovascular disease.[21] No protective effect against the development of stroke or all-cause mortality was seen in this population.[21] Eating a diet high in fish that contain long chain omega-3 fatty acids does appear to decrease the risk of stroke.[22] Fish oil supplementation has not been shown to benefit revascularization or abnormal heart rhythms and has no effect on heart failure hospital admission rates.[23] Furthermore, fish oil supplement studies have failed to support claims of preventing heart attacks or strokes.[5][6][7]
Evidence suggests that omega-3 fatty acids modestly lower blood pressure (systolic and diastolic) in people with hypertension and in people with normal blood pressure.[24] Some evidence suggests that people with certain circulatory problems, such as varicose veins, may benefit from the consumption of EPA and DHA, which may stimulate blood circulation and increase the breakdown of fibrin, a protein involved in blood clotting and scar formation.[25][26] Omega-3 fatty acids reduce blood triglyceride levels but do not significantly change the level of LDL cholesterol or HDL cholesterol in the blood.[27][28] ALA does not confer the cardiovascular health benefits of EPA and DHAs.[29]
The effect of omega-3 polyunsaturated fatty acids on stroke is unclear, with a possible benefit in women.[30]