is a "special product" specially used by mammals to feed the next generation. Milk is a kind of food with complete nutrient composition, suitable composition ratio, and easy to digest and absorb. Its extremely high nutritional value is unique among natural foods. Hippocrates, the father of medicine, once called milk "the closest food". Milk mainly provides high-quality protein, vitamin A, vitamin B2 and calcium. Proteins in milk account for about 3%, mainly whey protein and casein, with high digestibility, the proportion of amino acids meets human needs, and has high nutritional value. The fat content in milk is 3% to 4%, mainly saturated fatty acids, and exists in the form of tiny fat balls, which is easy to be digested and absorbed. Under natural conditions, the sugar (carbohydrate) in milk is mainly lactose. Milk is rich in vitamins and minerals, and is easily digested and absorbed.

　　Milk is the best source of dietary calcium, and its contribution to human calcium nutrition is almost irreplaceable. Milk not only has high calcium content (about 100 milligrams per 100 grams of milk), but also has a reasonable ratio of calcium and phosphorus. It also contains some factors that promote calcium absorption, so calcium absorption in milk is very high. A large number of studies have shown that drinking milk for children and adolescents can promote growth and development, especially for bone development and height growth, but also increase bone density and delay the age of osteoporosis in adulthood. Adult drinking milk can promote bone health and prevent osteoporosis, especially for women before and after menopause.

　　The results of the 2002 survey on nutrition and health status of Chinese residents showed that the calcium intake of urban and rural residents in China was obviously low, less than half of the recommended intake; the intake of dairy products was only in developed countries About 5%. To this end, the Chinese Nutrition Society has increased the recommended amount of milk and its products in the "Dietary Guidelines for Chinese Residents 2007". It is recommended that each person drink 300 grams of milk or equivalent milk products per day. This is not the maximum limit. Drinking more milk is also allowed, but when the milk consumption exceeds 300 grams per day, you should choose low-fat or skimmed milk and its products. Because milk and its products have a higher fat content and are mainly saturated fatty acids, and also contain cholesterol. When the amount of milk consumed is large (such as >300 grams per day), more saturated fatty acids and cholesterol are not conducive to cardiovascular System health. The so-called "low-fat" or "skimmed" milk refers to milk that uses a certain method to reduce or remove fat. Low-fat or skimmed milk is also more suitable for patients with hyperlipidemia, obesity or those who are obese.

　　Every person should drink 300 grams of milk or equivalent amount of milk products per day. In terms of the most common liquid milk, 300 grams is roughly 300 milliliters. The most common liquid milk packaging on the market is 250 grams per bag. This means that each person must choose one other milk product such as yogurt, cheese, milk powder, fruit-flavored milk, etc. on the basis of guaranteeing to drink a bag (250 grams) of milk every day to diversify the dairy products consumed .

　　 Drinking 300 grams of milk per day is recommended for children over 6 years of age and ordinary adults. "Dietary Guidelines for Chinese Residents 2007" also recommends: 4-6 years old preschool children should consume 300-600 grams of milk every day; 1 to 3 years old children should consume no less than 350 grams of liquid milk for children Formula milk powder, and it is not suitable to directly feed ordinary liquid milk or adult milk powder; infants from 6 months to 1 year old should consume 600-800 ml (or grams) of breast milk or infant formula milk every day; infants within 6 months are extremely large Some foods are milk.