Docosahexaenoic acid,22:6n‐3 (DHA) and its metabolites are vital for the structure and functional brain development of the fetus and infants, and also for maintenance of healthy brain function of adults. DHA is thought to be an essential nutrient required throughout the life cycle for the maintenance of overall brain health. The mode of actions of DHA and its derivatives at both cellular and molecular levels in the brain are emerging. DHA is the major prevalent fatty acid in the brain membrane. The brain maintains its fatty acid levels mainly via the uptake of plasma free fatty acids. Therefore, circulating plasma DHA is significantly related to cognitive abilities during ageing and is inversely associated with cognitive decline. The signaling pathways of DHA and its metabolites are involved in neurogenesis, antinociceptive effects, anti‐apoptotic effect, synaptic plasticity, Ca2+ homeostasis in brain diseases, and the functioning of nigrostriatal activities. Mechanisms of action of DHA metabolites on various processes in the brain are not yet well known. Epidemiological studies support a link between low habitual intake of DHA and a higher risk of brain disorders. A diet characterized by higher intakes of foods containing high in n‐3 fatty acids, and/or lower intake of n‐6 fatty acids was strongly associated with a lower Alzheimer's Disease and other brain disorders. Supplementation of DHA improves some behaviors associated with attention deficit hyperactivity disorder, bipolar disorder, schizophrenia, and impulsive behavior, as well as cognition. Nevertheless, the outcomes of trials with DHA supplementation have been controversial. Many intervention studies with DHA have shown an apparent benefit in brain function. However, clinical trials are needed for definitive conclusions. Dietary deficiency of n‐3 fatty acids during fetal development in utero and the postnatal state has detrimental effects on cognitive abilities. Further research in humans is required to assess a variety of clinical outcomes, including quality of life and mental status, by supplementation of DHA.

中文翻译：

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二十二碳六烯酸，22:6n-3：它在大脑结构和功能中的作用

二十二碳六烯酸,22:6n-3 (DHA) 及其代谢物对胎儿和婴儿的大脑结构和功能发育以及维持成年人的健康大脑功能至关重要。DHA 被认为是整个生命周期中维持整体大脑健康所需的必需营养素。DHA 及其衍生物在大脑细胞和分子水平上的作用模式正在出现。DHA是脑膜中主要流行的脂肪酸。大脑主要通过摄取血浆游离脂肪酸来维持其脂肪酸水平。因此，循环血浆 DHA 与衰老过程中的认知能力显着相关，与认知能力下降呈负相关。DHA 及其代谢物的信号通路参与神经发生、镇痛作用、抗凋亡作用、突触可塑性、脑疾病中的 Ca2+ 稳态以及黑质纹状体活动的功能。DHA 代谢物对大脑中各种过程的作用机制尚不清楚。流行病学研究支持 DHA 习惯性摄入量低与脑部疾病风险较高之间存在联系。以高摄入 n-3 脂肪酸和/或低摄入 n-6 脂肪酸为特征的饮食与较低的阿尔茨海默病和其他脑部疾病密切相关。补充 DHA 可改善与注意力缺陷多动障碍、双相情感障碍、精神分裂症和冲动行为以及认知相关的一些行为。然而，补充 DHA 的试验结果一直存在争议。许多 DHA 干预研究表明，对大脑功能有明显的好处。然而，需要临床试验才能得出明确的结论。胎儿在​​子宫内发育和出生后状态的饮食中缺乏 n-3 脂肪酸会对认知能力产生不利影响。需要对人类进行进一步研究，以通过补充 DHA 来评估各种临床结果，包括生活质量和精神状态。