Breast milk is the only natural, safe and complete natural food for infants to grow. It is rich in nutrients and contains all the nutrients and antibodies required by infants to ensure the normal and healthy development of infants. Some mothers give up breast-feeding because of busy work or lack of physical strength, resulting in inadequate nutritional supplies and physical weakness. In addition, the correct feeding method is also very important.
The nutritional value of breast milk is 1.2% protein (1.2g per 100ml), fat 3.5%, sugar (ie carbohydrate) 7.5%, minerals, vitamins, water and enzymes.
The proteins in breast milk are mainly lactalbumin and casein (about 2/3 is lactalbumin) and have very high nutritional value. Lactalbumin enters the stomach and acts with gastric juices and solidifies into tender and fine granular milk masses that are easily digested and absorbed. It also promotes the digestion of lactose. Casein is found in small amounts in breast milk. It enters the stomach and is used with stomach acid to solidify into larger milk masses, which is not as easily absorbed as lactalbumin. Breast milk also contains a small amount of lactoferrin, which can both supply iron and inhibit the role of E. coli (so breast-fed infants do not suffer from diarrhea). In addition, it also contains immunoglobulin, which can bind to bacteria and viruses in the intestine. Although the amount is small, it has a large effect and is good for disease prevention.
The fat ball of breast milk is very small and its diameter is 0.9-22 microns. The fat of breastmilk is mainly neutral lipids, namely soft fat, stearin and liquid fat, of which the liquid fat is the most. About 50% of breast milk's fat is dependent on the role of breast milk's own lipase, which breaks down into free fatty acids in children's stomach. This free fatty acid is an important source of energy for infants. In addition, the high level of linoleic acid in breast milk is one of the essential unsaturated fatty acids in the human body. If the fat content in breast milk is less than 2.0 g/100 ml, the nursing person must supplement the fat from the diet.
The sugar contained in breast milk is mainly lactose, which is completely dissolved in the emulsion, so it is easily digested and absorbed. Lactose can promote the propagation of certain lactic acid bacteria in the intestine, so that the proportion of spoilage bacteria is reduced, thereby having therapeutic and preventive effects on infant diarrhea. Lactose can also promote the absorption of calcium in food in the intestine, which is also particularly beneficial to the development of the baby's brain. If the lactose contained in the milk is less than 4 g/100 ml, the infant's needs cannot be met.
The total amount of minerals in breast milk is 0.15-0.25 g/100 ml. Among them, calcium is the main component, potassium, chlorine content is lower, phosphorus and sodium are again, magnesium, manganese, sulfur, iron, and copper are the least. Since the amount of iron in breastmilk is small (about 0.1-0.2g/100ml), if the baby is still the only food when it has grown to four or five months, in order to avoid anemia, iron supplementation should be started. food.
Breast milk contains many vitamins such as vitamins A, B, C, D, and K, as well as trace amounts of folic acid. In addition to vitamin D, other vitamins are generally not lacking in breast milk. In order to supplement vitamin D, suitable amount of cod liver oil should be added from the newborn period.
Breast milk contains enzymes that help food digestion, such as lipase (also known as lipase), amylase and catalase, etc., which contains more lipase, it can ensure the digestion and absorption of fat in breast milk.
The composition of breast milk is not fixed and will produce different changes at different stages. Different phases of milk (such as colostrum, mature milk, and late-stage milk) have different ingredients and are suitable for the needs of infants in different stages of growth.
The milk secreted from breast milk from delivery to 12 days after delivery is colostrum, 13-30 days is transitional milk, 2-9 months are mature milk, and 10-20 months are late milk.
Colostrum is yellow, white and thick, contains more protein, less fat, and has more solid components than regular milk. Colostrum contains a large amount of antibodies. Newborns can obtain the immune body from colostrum. Therefore, infants fed within six months of breastmilk rarely have measles, rubella, polio, mumps and other infectious diseases. Colostrum also has a laxative effect that helps newborns excrete meconium.
During the transition period, the milk fat content was higher. From then on, the secretion of milk juice gradually increased to meet the infant's rapid growth.
The ratio of protein, fat and carbohydrate in mature milk is approximately 1:3:6. This proportion of milk can be fully digested and absorbed by infants.
The composition of late-stage milk is not much different from that of mature milk, but milk has been reduced during this period.