It is believed that salt is the chief culprit that harms health. Therefore, the World Health Organization recommends that the salt intake per person per day should not exceed 5 grams. Excessive salt intake will cause high blood pressure and increase the burden on the heart, blood vessels and kidneys. Salt has a great influence on hypertension. Physicians have observed a phenomenon that the more salt you eat, the higher the incidence of hypertension. For example, Eskimos consume about 4 grams of salt every day, and there is almost no high blood pressure; The incidence of hypertension is 6.9% in people who consume 7 salts every day; In the United States, the incidence of hypertension is15g salt per day; Residents in northern Japan consume 26 grams of salt every day, and the incidence of hypertension is as high as 39%, and the proportion of deaths from hypertension and cerebral hemorrhage is also very large. In China, some areas in the south are used to sweets, and most dishes are flavored with sugar, so the incidence of hypertension is low, while some areas in the northwest are acidophilic and the incidence of hypertension is also low. In some areas of Tibet, residents even put salt in their tea, and the incidence of hypertension is around 20%, which shows how much salt affects our health. How much salt should we take in every day? Do not exceed 6 grams, which is more beneficial to the human body. Patients with hypertension and heart disease should eat less. If it is reduced to less than 5 grams, it can lower blood pressure and even eliminate hypertension. According to physiological knowledge, we know that the human body is short of sodium chloride, and the water in blood moves to tissues and cells, and the water in tissues increases, and cells swell and swell. Just like salted oysters put in fresh water, the human body will be swollen and swollen. Will this be good for your health? In particular, brain cell edema stimulates cells, showing symptoms such as nervous system inhibition, such as nausea, vomiting, fatigue, headache, lethargy, and unresponsiveness. Severe cell membrane rupture may occur; However, blood concentration, viscosity increase, smooth muscle spasm, colic of workers in high temperature workshop, spasmodic contraction of skeletal muscle and blood circulation disorder in different degrees. People will be general weakness, muscle contraction weakness and spasm, nerve information transmission will be affected, and even lead to death.
On the other hand, a person's 24-hour urine contains sodium130-261mmol (3-6g) and chlorine170-255mmol (4.8-7.2g). In terms of sodium, people excrete 7.6- 15.2 grams of sodium chloride from urine every day, and generally need 10- 15 grams of sodium chloride; Even if there is no salt in the diet, the human body still needs to excrete 2 grams of sodium chloride from the urine day and night, so human beings must consume more than 2 grams of sodium chloride every day. In addition, the human body will also lose a lot of salt when sweating. Therefore, 5 grams of salt is far from enough for the loss of salt in urine and the needs of human body. Especially for manual workers and athletes, 5 grams of salt is not enough. In fact, some people's diseases are caused by eating too lightly, such as some phlegm, asthma, cough, hyperlipidemia and so on. As long as you eat a little salty, you will be fine.
Salt is indispensable to the human body. If the human body is short of salt, people will be dizzy, tired and don't think about eating. In the long run, it will cause many diseases, white hair. In the hospital, we often see patients infusion, many of which are sodium chloride saline (that is, 0.9% saline).
Why does the concentration of normal saline have to be 0.9%? Let's analyze an interesting experimental phenomenon first.
About 200 years ago, in order to improve the method of brewing wine, people filled a round glass tube with alcohol, and then, at the lower end of the glass tube, it was sealed with animal bladder membrane. The lower end of the glass tube was immersed in water, and soon it was found that the bladder membrane bulged automatically. Obviously, this is water seeping into the alcohol tank through the bladder membrane. The swelling of the liquid in the cylinder is called osmosis, while the films such as bladder membrane, cell membrane, sheepskin and cellophane are called semi-permeable membranes.
The leakage phenomenon is regular. If the two kinds of brine are separated by a semi-permeable membrane, the water in the salt solution always permeates from the weak brine to the strong brine until the concentrations on both sides are equal.
Blood in the human body contains salt. Blood consists of red blood cells and liquid plasma. There are three kinds of blood cells: red blood cells, white blood cells and platelets, of which red blood cells account for the vast majority. The cell membrane is a semipermeable membrane. Under normal circumstances, intracellular solution and extracellular plasma solution must maintain a certain concentration. When people are infusion, the saline solution entering the plasma must also maintain a certain concentration, that is, 0.09%. If normal saline is diluted or distilled water is misused, the concentration of plasma will be diluted after infusion, so that the water in plasma will penetrate into blood cells with high concentration. As a result, blood cells swell or even rupture, leading to hemolysis. If the physiological saline is too thick, the water in the blood cells will seep out again. So generally speaking, normal saline must be 0.9%.
In case of special circumstances, such as severe dehydration of plasma caused by extensive burns, it is necessary to use less than 0.9% normal saline infusion to supplement the lack of water in plasma; If the patient's plasma water content increases due to excessive sodium loss, it is necessary to use more than 0.9% physiological saline infusion to increase the blood plasma concentration.
In our daily life, we often use the concentration of physiological saline. For example, in a hospital, eye drops should be prepared to a certain concentration, otherwise the eyes will be dehydrated or painful. When swimming, you won't feel pain when you open your eyes in seawater, but you will feel uncomfortable in fresh water. That's the reason. For example, when curing meat, we usually use strong brine to sterilize it, and the meat that loses moisture is easy to preserve.
Scientific research has proved that iodine deficiency disorder is an endemic disease with a clear cause. The only way to prevent this disease is to supplement iodine. How to supplement iodine? As a nutrient element, iodine supplementation participates in human metabolism, so it needs long-term, regular and trace. In other words, it is necessary to supplement iodine for many years, many times a day, and a small amount each time. Obviously, it is unscientific and difficult to make everyone supplement iodine by taking medicine or adding drinks and food every day. Practice shows that iodization with salt is a safe, effective, economical and simple method to supplement iodine! Everyone has to eat, and the iodized salt in the dish is a gift for those who lack iodine, which has no side effects on those who do not. Switzerland in Europe and Canada in North America have been implementing iodized salt for more than 20 years, and everything is normal. The safe range of human iodine intake is very large. From a medical point of view, it is safe to take 1000 micrograms of iodine every day. In fact, according to the investigation of relevant departments in China, people's iodine intake is generally only below 200-300 micrograms, so safety can be assured.
According to psychologists, the maximum daily salt intake is 6 grams, but now the average daily salt intake of most people is about 9.5 grams, which leads to many people suffering from cardiovascular diseases to varying degrees. If the daily intake of edible salt meets the standard requirements, the number of people suffering from myocardial infarction will decrease by 13%. At the same time, experts also pointed out that sea salt and mineral salt are essentially the same, and excessive consumption is harmful to human body. Finally, experts say that salt plays a key role in regulating the taste of food and coordinating the functions of various organs of human body, but the best effect can be achieved only by ingesting appropriate amount of salt, otherwise it will cause harm to human body.