必需脂肪(EFA)是婴幼儿正常生长发育和维持健康必需的物质,在营养学上是指体内不能合成,需从食物中摄取或补充的一类脂肪酸,其中长链多不饱和脂肪酸作用尤为重要。二十世纪60年代人们就发现食用n-3脂肪酸可预防心血管疾病。比如与西欧人相比,爱斯基摩人患心肌梗塞、糖尿病的几率明显减少,究其原因与爱斯基摩人膳食中的脂肪酸成分有关。他们每日摄入的EPA(二十碳五烯酸)和DHA(二十二碳六烯酸)可达5～10克,而摄入的饱和脂肪酸仅为西欧人的50%。二十世纪80年代进一步的研究表明,多不饱和脂肪酸在人体内具有广泛的生物学效应和生理功能,尤其表现在对脑功能和视网膜的发育上。大脑60%由脂质构成,主要是胆固醇和磷脂,磷脂中富含DHA和AA,这也就是我们称之为启智元素的主要理由。膳食脂肪酸很少以游离形式存在,主要是以由三分子高级脂肪酸和一分子甘油组成甘油三酯的形式存在。其中根据碳链中双键的位置不同可以将多不饱和脂肪酸(PUFA)分为n-3、n-6、n-9系列。其中n-3、n-6系列中常被我们提到的是由α-亚麻酸经生化演变(体内脱饱和、增加双键和延长碳链的过程)而来的二十二碳六烯酸(C22:6 n-3)即DHA和由亚油酸演变而来的花生四烯酸(C20:4 n-6)即AA。因此α-亚麻酸和亚油酸被认为是必需脂肪酸(EFA),也是n-3、n-6系列脂肪酸的母体。脑细胞膜磷脂含有大量多不饱和脂肪酸(PUFA),尤其是DHA和AA它们大部分集中在大脑皮质和视网膜。动物实验表明,在脑和视网膜发育过程中,对DHA和AA的需求量急增。如果孕妇妊娠期必需脂肪酸(EFA)供给不足会影响胎儿脑发育,还会使脑 Essential Fat (EFA) is essential for the normal growth and development and maintenance of health in infants and young children. In nutrition, EFA refers to a kind of fatty acid that can not be synthesized in the body and needs to be taken in or supplemented by food. The effect of long-chain polyunsaturated fatty acids is particularly important . In the 1960s people found that consumption of n-3 fatty acids prevented cardiovascular disease. For example, compared with Western Europeans, Eskimos suffering from myocardial infarction, diabetes significantly reduced the chances, the reason and Eskimos dietary fatty acid composition. Their daily intake of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) up to 5 to 10 grams, while the intake of saturated fatty acids is only 50% of Western Europe. Further studies in the 1980s showed that polyunsaturated fatty acids have a wide range of biological and physiological functions in the human body, especially in the development of brain function and the retina. Sixty percent of the brain is made up of lipids, mostly cholesterol and phospholipids, and is rich in DHA and AA in phospholipids, which is why we call it the element of enlightenment. Dietary fatty acids rarely exist in free form, mainly in the form of triglycerides consisting of three molecules of higher fatty acids and one part of glycerol. Polyunsaturated fatty acids (PUFA) can be divided into n-3, n-6 and n-9 series according to the position of the double bonds in the carbon chain. Among the n-3, n-6 series we often refer to the docosahexaenoic acid derived from the biochemical evolution of α-linolenic acid (in vivo desaturation, double bond increase and carbon chain extension) C22: 6 n-3) ie DHA and arachidonic acid (C20: 4 n-6) derived from linoleic acid, ie AA. Therefore, α-linolenic acid and linoleic acid are considered essential fatty acids (EFA), but also n-3, n-6 series of fatty acid precursors. Brain cell membrane phospholipids contain large amounts of polyunsaturated fatty acids (PUFA), especially DHA and AA, which are mostly concentrated in the cerebral cortex and the retina. Animal experiments show that in the brain and the development of the retina, the demand for DHA and AA surge. If pregnant women essential fatty acid (EFA) supply during pregnancy will affect fetal brain development, but also the brain