If you don't put some salt in your dishes when you eat, even 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. It regulates the balanced distribution of water in human body, maintains the osmotic pressure inside and outside cells, participates in the formation of gastric acid, promotes the secretion of digestive juice and can 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 can't do without salt. Eating too little salt will also lead to low sodium content in the body, loss of appetite, weakness of limbs and dizziness. In severe cases, anorexia, nausea, vomiting, accelerated heart rate, weak pulse, muscle spasm, blurred vision, weakened reflex and other symptoms may occur.

The chemical composition of salt is sodium chloride. Normal human body contains about100g of sodium, of which 40% is in bone, 50% in extracellular fluid, and10% is in intracellular fluid. The most abundant cation in extracellular fluid is sodium ion, which is an important substance to maintain the stability of human internal environment, that is, water electrolyte, acid-base balance, organ cell function and nerve and muscle excitability. When people are in severe diarrhea, blood loss, sweating, etc., or when food is very scarce and salt is extremely scarce, the human body will be obviously weak, weak, and even collapse and shock, which is life-threatening. Intravenous infusion of saline is often needed for treatment.

Primitive people had other ways to supplement sodium even if they didn't eat salt. Animals had to supplement themselves with salt.