Omega-3 fatty acids, also called n-3 fatty acids, are mainly alpha-linolenic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are one of the essential polyunsaturated fatty acid series. The omega-3 series of polyunsaturated fatty acids is a long chain of interconnected carbon-hydrogen atoms with 3-6 unsaturated bonds in the middle, and vegetable oils and fish oils are the main sources of them. Alpha-linolenic acid is the parent of the omega-3 family of fatty acids, and its carbon chain can be extended into longer chains of polyunsaturated fatty acids such as EPA and DHA. DHA is necessary to maintain the normal function of retinal pigment and also promotes fetal brain development.EPA can lower cholesterol and triglycerides, reduce blood viscosity and help prevent cardiovascular diseases such as atherosclerosis. It is recommended that the human body consume omega-3 series of polyunsaturated fatty acids in moderation, which helps to maintain the health of the organism.