Food has five flavors, namely, pungent, sweet, sour, bitter and salty. Different tastes have different physiological functions, such as: sweets can replenish qi and blood, detoxify and eliminate muscle fatigue; Sour spleen stimulates appetite and improves the absorption rate of minerals such as calcium and phosphorus; Bitter taste can dispel dampness and diuresis, and regulate liver and kidney; Spicy can stimulate the stomach, promote digestion, promote blood circulation and metabolism. Sour, sweet, bitter, spicy and salty flavors can complement each other, stimulate appetite and be beneficial to health. Improper, it will bring health risks, as the saying goes, "five flavors are out of balance, and all diseases are born in the body", such as: too many sweets affect appetite; Too much sour taste will make digestive function disorder; Excessive bitterness can cause indigestion; Excessive spicy can lead to oral ulcers, eye diseases, hemorrhoids and constipation.

Among the five flavors, "salty" is the most critical one. Some seafood and some meat are salty foods, but the most common and representative salting agent in life is "salt". In order to be healthy, we must control the intake of salt. It is almost a well-known truth that "more salt is lost".

Modern medicine has proved that the increase of diseases such as hypertension, arteriosclerosis, myocardial infarction, liver cirrhosis, stroke and nephropathy is closely related to excessive salt intake, which has become common sense. In China, northerners have a large amount of salt, which may be related to the regional climate. "Salt enters the kidney", and the dry, cold and appropriate salty taste in the north helps to protect the kidney's Yuanyang qi. But too salty will hurt the kidneys, and the northerners' dietary concept is "salty". They not only put more salt in cooking, but also often eat pickled products. Therefore, compared with the light and sweet eating habits in the south, the prevalence of hypertension showed a significant downward trend from north to south. Therefore, it is one of the important methods to control the incidence of hypertension to get out of the misunderstanding of "salty taste", change the eating habits of "heavy mouth" and salty taste, and arrange meals scientifically. In China's dietary guidelines, it is recommended to eat light and low-salt food, and it is suggested that the daily salt intake should be less than 6 grams. The World Health Organization recommends that the daily salt intake of patients with hypertension is 2 ~ 3 grams per person.