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I. Benefits and Harms of Salt (I) The benefits of salt start with the understanding of salt. What is salt? Salt is a white powdery solid, the main component is sodium chloride, which is composed of chloride ion and sodium ion. Sodium ions can provide pure salty taste, while chloride ions are taste AIDS. The sodium ion in salt is constant in plasma, and the concentration of sodium and chlorine in plasma has an important influence on osmotic pressure. At the same time, there are two main processes to adjust the sodium concentration: (1) is to control the loss of sodium; (2) It is the control of sodium intake. The content of sodium in extracellular fluid can be maintained at a relatively stable level, which is directly related to the following factors; Glomerular filtration rate, glomerular cells, renal angiotensin-aldosterone, systemic sympathetic nervous system, catecholamine concentration, circulating blood sodium-potassium relationship, the third factor, blood pressure. That is to say, sodium in sodium chloride is an indispensable chemical element in our body. There are about 6200-6900 mg of sodium in our body, which is widely distributed in various tissues and organs in the body, regulating water in the body, enhancing neuromuscular excitability, maintaining acid-base balance and normal blood pressure. Why is salt so important? This is because people will get sick because of insufficient salt intake; Without it, the heart cannot beat normally; Salt is the main raw material of gastric acid. If the body lacks chlorine, it will cause gastric acid deficiency, indigestion and loss of appetite. If you don't eat salt for a long time, people will feel weak, dizzy and twitch all over, which is called "salt loss" in medicine. Salt plays an important role in maintaining osmotic pressure of body fluids and acid-base balance, maintaining stress of nerves and muscles, and regulating physiological functions. . Salt can adjust the acid-base balance. In summer and autumn, people are prone to heatstroke and diarrhea, which can easily cause severe dehydration and electrolyte disorder. If you can't see a doctor immediately, you can use light salt mixed with salt to solve dehydration collapse caused by diarrhea and heatstroke. If you eat too little salt, your hair will turn white. The story of the white-haired girl is a good example. Xi was forced into the mountains by Huang Shiren and hid in a cave. A few years later, because she couldn't eat salt, her black hair became as white as snow. In many inland areas of China, iodine deficiency is a very serious problem. Adults suffer from goiter due to iodine deficiency, while children suffer from cretinism, also known as cretinism. Such children are not only short, but also seriously mentally retarded. In the 1990s, more than half of the junior middle school population lived in iodine-deficient areas. As long as people take iodine, this problem can be solved. But how to add it is a problem. Nutritionists in our country have studied the problem of iodizing salt. Later, the state forced people to add iodine to the salt that people can't live without every day. Salt is indispensable to us, and eating salt has fundamentally reversed this situation. Because of its remarkable achievements, the United Nations specially praised China's achievements, which is a great contribution of nutritionists in China. Moreover, when a large amount of extracellular fluid is lost (such as excessive bleeding and sweating) or food is short of salt, the content of sodium ions in the body decreases, and potassium ions enter the blood from cells, and diseases such as blood thickening, less urine and yellow skin will occur. Therefore, salt is very important and we can't live without it. Since it is so important, shouldn't we ask for more? Let's look at the harm of excessive salt intake. (2) The harm of excessive salt intake has always been "salty is fresh" in the diet of Chinese residents, especially in the north; "A good cook has a handful of salt"; The concept of "salty food is delicious" likes to eat salty things, commonly known as "heavy mouth". Long-term intake of a lot of salt is very harmful to health. It is pointed out in the Dietary Guidelines for Residents in China that the blood pressure level and the prevalence rate of hypertension are closely related to the salt intake. The prevalence of hypertension in the north of China is higher than that in the south, the average blood pressure in rural areas is higher than that in cities, and the salt intake is the same, that is, the north is higher than that in the south and the countryside is higher than that in cities. Clinical intervention treatment of hypertension confirmed that when salt intake increased, hypertension increased. If the daily salt intake is reduced by 2.4g, the average systolic blood pressure and diastolic blood pressure of healthy people can be reduced by 0.3kpa(2.3mmhg) and 0. 19kpa (1.4mmhg) respectively. The systolic and diastolic blood pressure of patients with hypertension can be reduced by 0.77kpa(5.8mmHg) and 0.33kpa(2.5mmHg) on average. It shows that salt intake directly affects blood pressure level. We all know that adding salt to fresh pig blood will coagulate pig blood. Of course, if we eat too much salt, our blood will become sticky, which will promote atherosclerosis and easily block up in tiny blood vessels. People who eat more salt are more likely to catch a cold, because high concentration of salt will inhibit the activity of respiratory cells and their disease resistance; At the same time, it also reduces saliva and lysozyme in the mouth, increasing the chance of upper respiratory tract virus and bacterial infection. Excessive salt is still the chief culprit of osteoporosis. Because the kidney excretes too much sodium with urine every day, every time it excretes 1000mg sodium, it loses about 26mg of calcium. Therefore, the more sodium the human body needs to excrete, the greater the consumption of calcium, which will inevitably affect the normal growth of bones. Excessive salt intake will not only induce hypertension, but also cause gastritis and peptic ulcer, and eating too salty will also disfigure your face. Life Times has published that "Eating too salty will ruin your appearance". (1), too much salt intake is easy to cause rough and dull skin, which is more obvious after sun exposure and wrinkles increase. Eating more salt will increase sodium ions in the body, lead to dehydration of facial skin cells, lead to skin aging, yellow face and increased wrinkles. (2) Excessive intake of salt, animal fat and protein will affect the normal metabolism of the liver, resulting in freckles and chloasma on the cheeks. (3) Eating too much salt will not only destroy metabolic alopecia, but also make hair yellow. Many foreign studies also show that eating too salty will increase the burden on the kidneys and further cause sodium excretion disorder, thus raising blood pressure. protein metabolic disorder will affect the formation of protein in the hair, making the hair color fade or even wither. There may be many reasons why some people eat less but are fat, but eating too salty may also be one of them. The water content in the body is closely related to the sodium chloride content. When the sodium chloride content in the body increases, the water content also increases. On the contrary, when the body lacks sodium chloride, the water content will also decrease. Excessive salt intake will cause water metabolism disorder, and water retention in the body cannot be ruled out, leading to edema and weight gain. Therefore, it is necessary to eat less salt if you want to be slim. Since too much salt won't do, and too little salt won't do, how much is appropriate? Second, the appropriate amount of salt The World Health Organization put forward the suggestion of 5g per person per day in 2006. However, in view of the dietary habits of Chinese residents, China Nutrition Society suggested that the daily salt intake of healthy adults should be 6g, and that of teenagers should not exceed 4g per person per day. We put salt in our cooking every day, and there are many foods containing hidden salt in our life. So what is hidden salt? As the name implies, it is the hidden sodium content in food. Sodium exists not only in salt, but also in soy sauce, soy sauce, pickles, monosodium glutamate, pickled fish, pickles and bacon. These are all salts that we ignore, and there are hidden salts in delicious snacks, so we should eat less of these foods.