鱼油的功过是非

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Fish oil -- helpful or harmful?
By BJS
Created 01/14/2008 - 14:59

Fish oil supplements may help some cardiac patients while harming others, suggests a new review of evidence compiled by St. Michael’s Hospital and University of Toronto researchers.

In a systematic review of trials where patients with implantable cardioverter defibrillators used fish oil supplements, Dr. David Jenkins and Dr. Paul Dorian found significant differences among the trials, indicating fish oil may be beneficial to some patients while having a negative impact on others.

“Fish oils can have complex and varied effects on the heart,” says Jenkins, a U of T Professor of Medicine who runs the Clinical Nutrition and Risk Factor Modification Centre at St. Michael’s Hospital. “These effects include blocking cardiac ion channels, reducing fibrosis in response to mechanical stress, decreasing blood coagulation, and possibly altering immune function.”

There is evidence from multiple large-scale population (epidemiologic) studies and randomized controlled trials that intake of recommended amounts of DHA and EPA in the form of dietary fish or fish oil supplements can reduce the risk of death, heart attack and dangerous abnormal heart rhythms in people with known cardiovascular disease, as well as potentially slow hardening of the arteries and lower blood pressure slightly. But the evidence also shows high doses can have harmful effects, such as an increased risk of bleeding. Although benefits are proposed for alpha-linolenic acid, scientific evidence is less compelling and beneficial effects may be less pronounced.

The meta-analysis reveals that studies in different patient populations with different pathophysiologies and therapeutic regimens have all produced divergent results. However, more recent data suggests that particular caution should be exercised when analyzing data from certain subgroups, such as men with stable angina. The same may also be true for patients with implantable cardioverter defibrillators who have a history of ventricular tachycardia and who are not taking antiarrhythmic medications.

“Fish oils have promise as beneficial in cardiovascular disease but our work highlights our gaps in understanding and the need for more research,” adds Dorian, a cardiologist at St. Michael’s Hospital and U of T Professor of Medicine University of Toronto.

The review, which will appear in the January 15 edition of the Canadian Medical Association Journal, also indicates that further research and large randomized controlled trials are needed before long-chain omega-3 fatty acids are used in patients with heart failure and angina.

Source URL:
http://www.scienceblog.com/cms/f ... -harmful-15228.html
多伦多大学医学教授，圣米迦勒医院临床营养和风险因子修正中心的Jenkins称，“鱼油可能对心脏各种复杂的作用”。“这些作用包括阻塞心脏的离子通道、减少由于机械压力而出现的纤维变性、减少凝血以及可能改变免疫功能。”
从多项大样本量（流行病学）研究及随机对照试验中得到证据，以鱼类膳食或鱼油补充剂的形式摄入推荐量的DHA和EPA，对于患有心血管疾病的人来说，除了可以潜在的减缓动脉硬化及轻微的降血压外，还可以减少死亡、心脏病发作及危险的心律失常风险。但是也有证据显示高剂量补充剂会有不良影响，例如增加出血风险。虽然服用补充剂的益处源于α-亚麻酸，但缺少具有说服性的科学证据，且益处也不是很显著。