Seven things to open the door: "rice, oil, salt, sauce and vinegar tea", which shows that salt is a necessity for people. Su Shi, a great writer in the Song Dynasty, wrote in his poem: "Don't you forget the taste? You can eat without salt in March?" If you don't put some salt in the dish when you eat, even the delicacies are like chewing wax. Salt is not only an important condiment, but also an indispensable substance to maintain the normal development of human body. Adjust the balanced distribution of water in human body, maintain osmotic pressure inside and outside cells, participate in the formation of gastric acid, promote the secretion of digestive juice, and stimulate appetite; At the same time, it also ensures the pH necessary for the action of pepsin, maintains the balance of pH in the body and the normal circulation of body fluids. People cannot live without salt. Eating too little salt can also lead to low sodium content in the body, loss of appetite, weakness of limbs and dizziness. In severe cases, there will be anorexia, nausea, vomiting, increased heart rate, weak pulse, muscle spasm, blurred vision, weakened reflex and other symptoms. In ancient times, the Netherlands, Sweden and other countries stipulated that people who violated the criminal law were not allowed to eat salt as punishment for a period of time.

However, eating too much salt is also harmful to the human body. The results of scientists' research show that salt can "replenish water" to the human body, that is to say, salt has a certain adsorption force on water. If there is more salt in the human body, it is necessary to increase the water accordingly, so that too much water stays in the body, thus causing high blood pressure. Someone has investigated the eating habits of residents in northern Tokyo, Japan. They eat an average of 25 grams of salt every day, and people with hypertension account for 30 ~ 40% of all residents. In other parts of the world, people only eat 5 ~ 15g of salt every day, and only 8 ~ 10% of them suffer from hypertension. Eskimos living in the Arctic Circle eat less than 5 grams of salt every day, and almost no one suffers from high blood pressure. Therefore, experts suggest that adults should not eat more than12g of salt every day.