Polyunsaturated fatty acids, also called polyenoic acids, refer to fatty acids containing 2 or more unsaturated double bonds in their molecular structure. The more double bonds there are, the higher the degree of unsaturation and the higher the nutritional value. With the development of science, the effects of certain polyunsaturated fatty acids on the human body are further understood, especially docosahexaenoic acid, eicosapentaenoic acid and linoleic acid in general vegetable oils (often combined with linolenic acid** Polyunsaturated fatty acids represented by *Cun) and others have attracted more and more attention. Let’s talk about a brief understanding of the role of polyunsaturated fatty acids on the human body.

1 Polyunsaturated fatty acids are special nutrients for the prevention and treatment of cardiovascular and cerebrovascular diseases

Many people are aware of this phenomenon. In modern society, cardiovascular and cerebrovascular diseases are increasingly threatening Human health and life, the number of deaths caused by cardiovascular and cerebrovascular diseases represented by hypertension, hyperlipidemia, arteriosclerosis, coronary heart disease, thrombosis, etc. has ranked first among all types of diseases at a rate of 40%, facing the threat of death , many people are looking for the cause and prevention and treatment methods. In the late 1960s, scientists accidentally discovered that the Greenland Eskimos living in the Arctic ice sheet had almost no cardiovascular and cerebrovascular diseases, while Europeans and Americans had the highest incidence rates, and Asian Japanese had lower incidence rates. It turns out that the Eskimos have a unique diet of "raw fish and seal meat" in the world, which is rich in the most effective substances for preventing and treating cardiovascular and cerebrovascular diseases. The fat of fish meat contains unique n-3 series polyunsaturated fatty acids - Docosahexaenoic acid (DHA), Docosapentaenoic acid (NPA), Eicosapentaenoic acid (EPA), and Eicosapentaenoic acid. enoic acid, stearidonic acid, etc. The high content of polyunsaturated fatty acids in fish fat is unmatched by other foods. Cardiovascular and cerebrovascular diseases are mainly caused by atherosclerosis, and hyperlipidemia is the primary risk factor for atherosclerosis. Therefore, correcting hyperlipidemia plays an important role in preventing and treating cardiovascular and cerebrovascular diseases. Polyunsaturated fatty acids have the following effects on lipid metabolism in the human body: (1) Promote cholesterol metabolism and prevent lipid deposition in the liver and artery walls. Cholesterol in human blood can come from food or can be synthesized by the liver. The former is exogenous and the latter is endogenous. Although cholesterol is a component of higher eukaryotic cell membranes and is necessary for cell growth and development, excessive cholesterol content in serum will accumulate on the walls of coronary arteries and cause coronary heart disease. When there is a lack of polyunsaturated fatty acids in the diet or too much saturated fatty acids are taken in, saturated fatty acids can stimulate bile secretion and promote the absorption of dietary cholesterol, resulting in excessive cholesterol levels in the blood; when there is an abundance of polyunsaturated fatty acids in the diet, cholesterol will It combines with it to form cholesterol ester, which promotes the formation of bile acid and is excreted from the intestines. Famous nutritionist Keys has always believed that blood cholesterol levels have little to do with dietary cholesterol intake. However, blood cholesterol is directly proportional to the dietary intake of saturated fatty acids and inversely proportional to the dietary intake of unsaturated fatty acids. Therefore, an appropriate intake of a certain amount of polyunsaturated fatty acids in the diet can promote the body's cholesterol metabolism, reduce the total cholesterol content in the serum, prevent lipid deposition in the liver and arterial walls, and prevent cardiovascular and cerebrovascular diseases (mainly coronary heart disease). ) is helpful. According to research, the EPA and DHA contained in marine fish oil are the main components in preventing coronary heart disease.

(2) It can increase the high-density lipoprotein content in serum and has a certain effect on reducing blood lipids. Since cholesterol is a fat-soluble substance, it must be combined with proteins to form lipoproteins in order to be dissolved in the blood and transported in the body. There are two types of cholesterol lipoproteins in the human body, namely high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). When cholesterol exists in the blood in the form of low-density lipoprotein, it is easy to be deposited on the blood vessel wall. When it exists in the blood in the form of high-density lipoprotein, it can remove cholesterol on the blood vessel wall, dredge the blood vessels and protect the heart. . Therefore, high-density lipoprotein in human serum is a protective factor for cardiovascular and cerebrovascular diseases, while low-density lipoprotein is one of the culprits in atherosclerosis. After the saturated fatty acids ingested in the meal are absorbed, triglycerides are formed in the liver and then converted into low-density lipoproteins. Saturated fatty acids can inhibit the activity of low-density lipoprotein receptors, thus reducing the elimination of cholesterol in the blood. The absorption of cholesterol increases, the synthesis of blood lipids increases, and the elimination decreases, thus increasing blood lipids. After polyunsaturated fatty acids are digested and absorbed, they do not form triglycerides and low-density lipoproteins in the liver, but combine with apolipoproteins secreted by liver cells to form high-density lipoproteins (HDL). HDL serves as a receptor for cholesterol and Cholesterol is combined to form HDL-C, which is then transported into liver cells through blood circulation. The cholesterol forms bile acids and is excreted out of the body for elimination, thus lowering blood lipids and helping to fight atherosclerosis.

(3) It can reduce the aggregation ability of platelets and reduce the generation of thrombus. Vasoconstriction and platelet aggregation are another important factor in atherosclerosis and promote blood coagulation and cause embolism. Polyunsaturated fatty acids (mainly EPA) can increase the activity of phosphoprotein esterase, inhibit platelet aggregation, and promote the decrease of plasma glycolipid, cholesterol, and triglyceride indexes. EPA can also increase the thrombolytic effect of tissue fibrinolytic activator, reduce fibrinogen levels and blood viscosity, and increase blood fluidity, thereby preventing the formation of thrombus and reducing the incidence of atherosclerosis.

(4) After the inflammatory reaction of blood vessels, it will promote the deposition of lipids on the arterial wall and cause the occurrence of atherosclerosis. Polyunsaturated fatty acids can strengthen the production of white blood cells on the damaged surface of blood vessels. function, thereby reducing the inflammatory response and delaying the process of vascular sclerosis in the damaged part of the blood vessel.

(5) Polyunsaturated fatty acids can promote the function of the human body’s defense system and make the fatty acid profile in the blood develop in a direction beneficial to human health, thus helping to prevent other diseases that can cause and aggravate cardiovascular and cerebrovascular diseases. occur.

2 Polyunsaturated fatty acids help strengthen the brain and improve eyesight

Polyenoic acids such as DHA contained in fish oil and breast milk are themselves important substances that make up brain cells and cranial nerves. , which is necessary for the growth and development of brain cells and brain nerves and to maintain normal operation. It can also promote the formation of neural networks, improve cardiovascular and cerebrovascular functions and brain blood supply, improve the brain's self-nutrition system, and play a significant repair role in brain cells that have shrunk and died due to age and other factors. Therefore, DHA is essential for intellectual processes such as memory and thinking. Docosapentaenoic acid (NPA) can activate brain neurotransmitters, greatly speeding up information transmission and processing, and is therefore the key to determining the brain's response ability. If the supply of n-3 polyunsaturated fatty acids is insufficient during the fetal period, the division and proliferation of fetal brain cells will be hindered. A severe lack of polyunsaturated fatty acids will cause delayed brain cell development and low intelligence.

N-3 polyunsaturated fatty acids are also essential nutrients for the retina of the eye. Its deficiency is the root cause of many eye diseases and low vision in children.

3 Intake should be appropriate

If too much polyhydric saturated fatty acid is taken in, the unsaturated double bonds in its structure will undergo a peroxidation reaction and produce peroxidized lipids. This is a free radical that is one of the risk factors for aging and cancer. If this peroxidized lipid appears in the skin, it will form lipofuscin and cause age spots; if it appears in the cells, it will weaken the cell function; obese patients may easily cause cholelithiasis if they consume too much unsaturated fatty acids. Studies have shown that the increase in lipid peroxide in the blood is more harmful to the formation of atherosclerosis than the increase in cholesterol. Nutritionists from the Chinese Academy of Preventive Medicine put forward the "food pyramid" model in order to improve people's health. The top layer of the pyramid is oil, which is divided into animal fat and vegetable oil. Generally, animal fat contains higher saturated fatty acids (except fish oil). The "dietary goal" proposed by the United Nations World Health Organization is that fat accounts for 30% of total energy intake. The American Heart Association, Food and Nutrition Board, and American Medical Association further recommend that saturated, monounsaturated, and polyunsaturated fatty acids should comprise 10 percent each of the diet. Japanese researchers further proposed that an average daily intake of 200 to 500 mg of n-3 unsaturated fatty acids can reduce coronary heart disease mortality by 30% to 50%, which is equivalent to a daily intake of 30g of fish, that is, the intake of n-3 fatty acids The amount should be 350 to 400 mg per day.

With the improvement of living standards, in our daily life, on the premise of ensuring a diversified food intake, we should also pay attention to the dietary balance of lipid nutrition, not only to prevent excess animal fat, but also to Prevent excessive intake of vegetable oils to prevent new nutritional disorders.

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< p>If you have any questions, you can leave a message in my space. If you need help, please contact me anytime. Hope this helps.