The health benefits of fish oil, and its omega-3 long chain polyunsaturated fatty acid content, have attracted much scientific attention in the last four decades. Fish oils that contain higher amounts of eicosapentaenoic acid (EPA; 20:5n-3) than docosahexaenoic acid (DHA; 22:6n-3), in a distinctive ratio of 18/12, are typically the most abundantly available and are commonly studied. Although the two fatty acids have traditionally been considered together, as though they were one entity, different physiological effects of EPA and DHA have recently been reported. New oils containing a higher quantity of DHA compared with EPA, such as fractionated and concentrated fish oil, tuna oil, calamari oil and microalgae oil, are increasingly becoming available on the market, and other oils, including those extracted from genetically modified oilseed crops, soon to come. This systematic review focuses on the effects of high DHA fish oils on various human health conditions, such as the heart and cardiovascular system, the brain and visual function, inflammation and immune function and growth/Body Mass Index. Although inconclusive results were reported in several instances, and inconsistent outcomes observed in others, current data provides substantiated evidence in support of DHA being a beneficial bioactive compound for heart, cardiovascular and brain function, with different, and at times complementary, effects compared with EPA. DHA has also been reported to be effective in slowing the rate of cognitive decline, while its possible effects on depression disorders are still unclear. Interestingly, gender- and age- specific divergent roles for DHA have also been reported. This review provides a comprehensive collection of evidence and a critical summary of the documented physiological effects of high DHA fish oils for human health.

中文翻译：

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高DHA鱼油如何影响健康？系统地审查证据

鱼油的健康益处及其omega-3长链多不饱和脂肪酸的含量在过去的40年中引起了科学界的广泛关注。鱼油中二十碳五烯酸（EPA; 20：5n-3）的含量高于二十二碳六烯酸（DHA; 22：6n-3），其比率为18/12，是最丰富的鱼油，通常进行研究。尽管传统上将两种脂肪酸一起考虑，尽管它们是一个整体，但最近已报道了EPA和DHA的不同生理作用。与EPA相比，DHA含量更高的新油，例如分馏和浓缩鱼油，金枪鱼油，枪乌贼油和微藻油，以及越来越多的其他油，包括从转基因油料作物中提取的油，即将来临。这篇系统的综述着眼于高DHA鱼油对各种人类健康状况的影响，例如心脏和心血管系统，大脑和视觉功能，炎症和免疫功能以及生长/身体质量指数。尽管在某些情况下报告了不确定的结果，而在其他情况下却观察到不一致的结果，但当前数据提供了充分的证据支持DHA是有益于心脏，心血管和脑功能的生物活性化合物，与EPA相比具有不同的，有时是互补的作用。据报道，DHA可有效减缓认知能力下降的速度，但其对抑郁症的可能影响尚不清楚。有趣的是，DHA在性别和年龄方面的差异作用也已有报道。