必需脂肪酸(EFA)的定义不明确:“基本”这个词可以解释在一个狭窄的方式,即一个必然需要的饮食,因为人体不能合成,或在一个更扩展方式,即对于一个人的生活,包括这样一个更大数量的脂肪酸。在这两种情况下，它仍然是富含双键或不饱和的长链脂肪酸(因此简称PUFA:多不饱和脂肪酸)，这使得这些脂肪酸的结构更加流动和灵活。这一事实很重要，因为细胞膜(包括神经元)等结构中富含脂肪酸。从有限的“必需”一词来看，真正必需的脂肪酸只有两种，即不能由人体合成的脂肪酸(因此也称“维生素F”):α -亚麻酸(ω3 -ω3)和亚油酸(ω6 -ω6)。单词后面的数字表示从最后一个碳原子到第一个双键的碳原子数量。考虑到广义的“本质”一词，它可以包括两系的所有多不饱和脂肪酸，即ω3和ω6。在“非必需”物质中，众所周知的是二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)，它们是构成神经冲动传递的突触膜磷脂的基本物质，越来越多地出现在孕妇和儿童早期的营养补充剂和特殊食品中，因为它们在胎儿和儿童的正常神经元和视觉发育中发挥着关键作用。ω3主要存在于脂肪多的鱼类中(鲑鱼、鲭鱼、凤尾鱼等)。 The alpha-linolenic acid (essential) is contained in nuts and cold- extracted soybean and corn oils. ω6 are found primarily in cold- extracted vegetable oils but also in some cereals, legumes and vegetables. The population as a whole has often shortage of ω3, rarely ω6. Polyunsaturated fatty acids have many important functions: they are precursors of substances with hormonal effect, called eicosanoids (prostaglandins, thromboxanes, leukotrienes, etc.), they are essential for proper fetal and infant development, energy production, proper functioning of cellular and intracellular membranes (e.g. nucleus and mitochondria), synthesis of hemoglobin, blood clotting, health of skin and joints, sexual function and reproduction, improved glucose tolerance in diabetics, etc. One of the most well-known effects of PUFAs, which is “attractive” for the production of fortified food by the food industry, consists in the power of these substances to reduce blood levels of triglycerides and total cholesterol, and in particularly “harmful” cholesterol, i.e. LDL, resulting in substantial benefits in terms of cardiovascular health. It also seems that PUFAs play an important role in the prevention of neurological diseases such as depression. For all the above mentioned benefic effects, which are now well known to consumers, since for years supported by scientific evidence, food fortification through essential fatty acids is a promising business. This operation, however, is not always easy, since it poses a number of challenges not indifferent to food technology. Let us consider the most critical aspects. Lipid nature: Since they are substances of lipid nature, their intake is simple only in the case of food of the same nature, e.g. fats and creams, or eggs (whose fortification is obtained by adding PUFAs to the diet of laying hens).
