1, protein in milk
The content of protein in milk is 3%~3.7%, mainly casein and whey protein, and a small amount of lipid globular membrane protein. Protein is one of the important parts of human body. What the human body needs for protein is actually the need for amino acids.
There are 20 main amino acids in milk protein, including lysine, methionine, phenylalanine, threonine, tryptophan, valine, leucine and isoleucine, and 8 essential amino acids. Therefore, protein in milk is a kind of high-quality protein, which can provide eight essential amino acids for human body.
Special instructions:
In the protein of wheat, barley, oats, rice and corn, the content of lysine is very small; Protein in peanuts and soybeans contains less methionine. Therefore, when eating steamed bread, rice, oatmeal, corn, peanuts and bean products, milk can be matched to avoid the lack of lysine and methionine in human body, so that protein can be easily digested and absorbed by human body.
In the protein of wheat, barley, oats, rice and corn, the content of lysine is very small; Protein in peanuts and soybeans contains less methionine.
2. Lactose in milk
The lactose content in milk is 4.5%~5%.
Usually, lactose is the main sugar that babies eat. Lactose can maintain the optimal number of intestinal bacteria in infants' intestines and promote the absorption of calcium. Therefore, milk is the main source of sugar for infants.
3. Vitamins in milk
Milk contains vitamin A, vitamin D, vitamin B 1, vitamin B2, nicotinic acid, vitamin B6, pantothenic acid, biotin, folic acid, vitamin B 12, vitamin C, vitamin E, choline and inositol. Vitamins are essential nutrients to maintain normal physiological functions of human body. Milk is the best source of vitamins.
4. Minerals in milk
Milk mainly contains minerals such as calcium, magnesium, iron, sodium and potassium, as well as trace amounts of iodine, copper and zinc.
Calcium is an important component of bones and teeth. 100g milk contains 100 ~ 120mg calcium. Protein and lactose in milk can promote the absorption of calcium, and calcium in milk is easily absorbed and utilized by human body. Therefore, milk is the most ideal calcium source for infants.
5. Cholesterol in milk
Cholesterol is an important component of human cell membrane. It is reported that the average daily cholesterol intake of normal people is 106~254 mg.
High blood cholesterol is related to cardiovascular diseases. The cholesterol content in milk is low, 100 g of milk contains cholesterol 13 mg. Therefore, drinking milk will not cause high blood cholesterol.
Second, the shortcomings of milk
1, lactose intolerance in milk
About 40% of children, the secretion of lactase in small intestine is reduced or the activity is not high, and the lactose in milk cannot be digested and decomposed, and some lactose is fermented into lactic acid, hydrogen, methane and carbon dioxide by colon flora. Lactic acid stimulates intestinal wall, increases intestinal peristalsis and causes diarrhea. Therefore, children with lactase deficiency or low lactase activity, drinking milk will cause diarrhea.
With the increase of age, the activity of lactase in the intestine drops sharply, or even has no activity at all. Therefore, when adults drink milk, the lactose in it is not easy to digest, and some people will also cause diarrhea.
2. protein allergy in milk.
Due to environmental pollution, different constitutions and excessive use of antibiotics, the flora in the human body will be unbalanced, which will cause allergic reaction (abnormal immune reaction) to protein in milk, causing diarrhea and skin eczema. For babies, it is milk protein allergy.
Special instructions:
(1) Lactose intolerance: sour mouth, more farts, sour stool and frothy stool during diarrhea.
(2) Milk protein allergy: repeated spitting of milk, diarrhea, smelly but not sour stool, no foam in stool, mucus in blood, accompanied by skin eczema.
(3) Lactose-intolerant people should not drink milk, but choose lactose-free milk.
(4) People who are allergic to milk protein should not drink milk, and should choose formula milk powder deeply hydrolyzed in protein.
It is concluded that drinking milk can replenish water and high-quality protein for human body, and provide 8 essential amino acids for human body.
Drinking milk can provide sugar sources (not breastfeeding), vitamins and minerals such as calcium.
When eating steamed bread, rice, oatmeal, corn, peanuts and bean products, it can be matched with milk to avoid the lack of lysine and methionine in human body, so that protein can be easily digested and absorbed by human body.
Infants and adults who are lactose intolerant should not drink milk, and should choose lactose-free milk.
Infants who are allergic to milk protein should not drink milk, and formula milk powder with deep hydrolysis of milk protein can be used.
Drinking milk will not lead to high blood cholesterol.