Can I continue to drink milk？ Experts answer your questions.

　　Figure/vision china

　　Cover of colostrum basic protein CBP and bone health

　　□ Xue Qingxin

　　"A glass of milk every day makes Chinese strong" is a classic milk slogan that many people are very familiar with. Drinking milk often is good for health. All along, China has been vigorously promoting the benefits of drinking milk. I hope everyone can drink milk every day.

　　Not long ago, the 2022 edition of Dietary Guidelines for Residents in China was published. Compared with the 2016 edition of Dietary Guidelines for Residents in China, the new guidelines put special emphasis on milk intake. The original version recommended that the intake of milk and dairy products be 300g/day, but the recommended amount in the 2022 version has been increased to 300g-500g/day.

　　This change further confirms the importance of drinking milk, and also reflects the importance China attaches to drinking milk.

　　Even so, there will still be many different voices on drinking milk, and there are even people who strongly oppose drinking milk.

　　But there are still many misunderstandings about milk.

　　answer questions

　　Drinking milk has hormones, and drinking it often can lead to precocious puberty? Not really!

　　There are two sources of estrogen in milk: one is the natural estrogen contained in milk itself, which comes from the natural secretion of dairy cows during milk production; The other is artificially added estrogen, which is mainly used for infertility and cow disease treatment. Among them, the content of natural estrogen in milk is very low, which is not harmful to human body, and many common natural foods contain estrogen or estrogen-like, such as meat and bean products, and even breast milk contains estrogen, which is often higher than milk. The artificially added estrogen will of course be restricted by the state. China’s "Regulations on the Administration of Veterinary Drugs" clearly stipulates estrogen drugs, and related drugs may not be detected in animal foods. Therefore, as long as it is milk purchased by regular manufacturers, you don’t have to worry too much about estrogen.

　　In addition, there is no evidence that drinking milk will lead to precocious puberty or damage children’s health. On the contrary, many studies show that the intake of milk and its products can increase the bone density of children, adolescents and postmenopausal women, which is beneficial to the growth and development of children.

　　Adults drinking milk will not cause cancer. Studies have shown that milk and its products have nothing to do with the risks of breast cancer and prostate cancer. And drinking milk often may also reduce the risk of breast cancer by 16%, and drinking 200 grams of dairy products every day can reduce the risk of colon cancer by 7%.

　　Therefore, on the whole, as long as it is milk produced by regular manufacturers, you don’t have to worry about cancer, so drink it with confidence.

　　Milk and citrus fruits are the same? Rest assured to eat!

　　There are rumors among the people that milk and citrus fruits are alike and cannot be eaten together, because milk will denature and precipitate after encountering citric acid in oranges, which will lead to stones.

　　The truth is that when milk meets citrus fruits, precipitation may indeed occur. This is because the organic acid in the fruit breaks the acid-base balance. When the pH value just reaches the isoelectric point of protein, protein particles in milk are easily collided and condensed because of the weakened intermolecular force, and thus flocculent precipitation will occur. But these deposits are also edible, and many cheeses are produced in this way.

　　Even if you don’t eat it with fruit, milk will precipitate and solidify after encountering stomach acid. Therefore, milk and citrus fruits can be safely eaten together, without poisoning or stones.

　　Lactose intolerance: Do you want to quit milk? Actually, no!

　　Lactose intolerance is very common in China. Lactase that decomposes lactose is lacking in the intestines of these people, and discomfort will occur after drinking milk, such as abdominal distension, abdominal pain and diarrhea. But even if there is lactose intolerance, it does not mean that it is necessary to quit milk.

　　It is recommended to try the following four methods:

　　① Drink yogurt: During the fermentation of yogurt, lactose will be decomposed by microorganisms to produce lactic acid, which will reduce the lactose content and relieve the symptoms of lactose intolerance. Another study shows that increasing the intake of yogurt can improve the symptoms of lactose intolerance.

　　② Drink 0 lactose or low lactose milk: It is very suitable for lactose intolerant people to drink by using special technology to hydrolyze lactose in milk.

　　③ People who are only slightly lactose intolerant can try to improve lactose tolerance: drink 60-120g pure milk 2-3 times a day for 3 weeks after each meal, and gradually induce the intestine to enhance lactose tolerance.

　　④ Low-salt cheese: According to protein ratio, 10 grams of cheese is equivalent to 100 grams of milk.

　　Is the milk with long shelf life because of preservatives? fault

　　Many milk on the market has a shelf life of up to 6 months, so some people think that it is secretly added with preservatives.

　　In fact, there is no need to add preservatives to milk, and the shelf life depends on the sterilization method of milk.

　　The shelf life of pasteurized milk is generally short, usually 7 days, and it needs to be stored in cold storage; However, milk sterilized at ultra-high temperature instantly kills almost all microorganisms and bacteria during sterilization, so it can still be preserved for a long time without preservatives, generally up to 6 months, and can be stored at room temperature.

　　Now there are many transparent packaging bags of milk on the market, the price is relatively high, which can directly see the true color of milk and give people a very fresh feeling. Many consumers also prefer to buy this kind of milk, thinking it is more nutritious and more comfortable to drink. In fact, transparent packaging bags do not mean that milk is fresher and more nutritious. Vitamin B2 in milk is a photosensitive substance, which is unstable under light. However, milk in transparent packaging bags is often directly exposed to sunlight and light, which may increase the loss of vitamin B2 in milk.

　　However, opaque milk packaging can be stored away from light, which can better preserve the nutrition in milk.

　　remove a doubt

　　Continue to drink milk. Is a kilo a day enough?

　　Most people in our country don’t drink enough recommended milk.

　　According to the Scientific Research Report on Dietary Guidelines for Residents in China 2021, in 2015, the per capita milk intake in Chinese cities only reached 14% of the recommended amount in the 2016 edition of Dietary Guidelines, and it will be lower in rural areas. In other words, most people in China don’t drink enough milk. Milk is a good source of calcium supplement. If milk intake is insufficient for a long time, it may increase the risk of calcium deficiency.

　　Milk can not only supplement calcium, but also provide high-quality protein and vitamin B2. Lactose in milk can also promote the absorption of minerals such as calcium, iron and zinc.

　　The recommended milk intake in the 2022 edition of Dietary Guidelines for China Residents has increased to 300 -500 grams per day — — A kilo (500g) of milk a day is actually necessary. For special people with high calcium demand, it is still difficult to make up enough calcium even if they insist on drinking 300 grams of milk every day. For example, teenagers, women in the second and third trimester of pregnancy, nursing mothers and people over 50 can only supplement 321 mg of calcium if they drink 300 g of milk every day, which means they need to take 500 mg -900 mg of calcium from other foods.

　　In addition to milk, green leafy vegetables and bean products are also sources of calcium supplementation, but influenced by phytic acid and oxalic acid, the absorption rate is mostly not as good as that of milk. For example, the calcium absorption rate of tofu is only 15%; The calcium content of celery is 191 mg /100 g higher than that of milk, but the oxalic acid content is as high as 231 mg /100 g, the available calcium is only 79 mg /100 g, the leek calcium content is 105 mg /100 g, the oxalic acid content is as high as 162 mg /100 g, and the available calcium is only 34 mg /100 g. (Editor’s Note: Phytic acid can produce insoluble compounds with metal ions such as calcium, iron, magnesium and zinc; Oxalic acid can reduce the bioavailability of mineral elements, and it is easy to form calcium oxalate with calcium ions in human body, leading to kidney calculi).

　　I really don’t like drinking milk. How can I supplement my nutrition?

　　There are some people who just don’t like the taste of milk or are allergic to dairy products, so they really can’t drink milk to supplement calcium. There are also some friends who are always suspicious of milk and are unwilling to drink it. So how can these people get enough calcium?

　　For people who don’t like the taste of milk, milk and fruit can be made into milkshakes, such as strawberry milkshakes, banana milkshakes, mango milkshakes, etc., and the taste is mostly acceptable; You can also make custard and steamed bread with milk or milk powder; Yogurt and cheese are also good choices. According to protein ratio, 12.5 grams of milk powder is equivalent to 100 grams of milk.

　　For people who are allergic to milk, they can’t eat any dairy products, and they often worry about insufficient calcium intake. It is suggested to choose vegetables with high calcium content, such as rape, Chinese cabbage, radish tassel, fennel and coriander, while vegetables with high oxalic acid, such as spinach, amaranth, water spinach and celery, can be blanched before eating. Eat 300 -500 grams of vegetables every day, and the cooked vegetables are about 100 grams in size.

　　Bean products are recommended to eat at least 50 grams of soybeans, such as two fist-sized tofu or four pieces of dried tofu or 1.5 fist-sized shredded tofu.

　　In addition, calcium can also be supplemented appropriately. It is recommended to choose a small dose, preferably 100 -300 mg of calcium per tablet, which can be supplemented flexibly.

　　If you drink milk, you will get acne. What should I do?

　　Many friends actually like to drink milk, but it is helpless that when they drink milk, their faces will explode. This situation may be due to food intolerance to milk. Casein in milk can promote the secretion of insulin and IGF-1, leading to acne.

　　In particular, skim milk may be more serious than whole milk, so it is also mentioned in the China Acne Treatment Guide (2019 Revision) that if you have acne, you should pay special attention to limiting the intake of skim milk, and you can try sugar-free yogurt and low-salt cheese.

　　Some people also like to use milk as a mask, thinking that drinking milk and smearing milk can whiten the skin. In fact, this statement is unfounded. Black people also drink milk, and their skin color is still black.

　　The main ingredients of milk are water, protein, fat, calcium, etc. These ingredients have no special effect on whitening, even if you wash your face with milk every day, it will not whiten.

　　Skin color is closely related to genetic factors and environmental factors, and it cannot be changed by eating any kind of food. Drinking milk is recommended, but don’t expect whitening; As for washing your face with milk, don’t waste it again.

　　summary

　　From the point of view of calcium supplementation and disease prevention, it is necessary to have 300 -500 grams of milk every day. If you especially like to drink milk and drink more than 500 grams a day, then it is more recommended to choose low-fat milk, or reduce the intake of other oils in moderation, and avoid the total energy exceeding the standard.

　　(Source: "Science Rumors" WeChat official account)

　　interlinkage

　　Interview with Lou Wenyong, Professor of South China University of Technology;

　　If you want to supplement calcium, besides drinking milk, you should also supplement CBP.

　　Text/Yangcheng Evening News reporter Sun Lei

　　South China University of Technology Press timely published a popular science book "Basic Protein CBP in Colostrum and Bone Health", which was co-edited by Professor Lou Wenyong of South China University of Technology, Dr. Zeng Yingjie of Southwest University for Nationalities and popular science author Li Daiwei.

　　The book emphasizes that a colostrum basic protein (CBP) can directly act on bone cells, promote osteoblast proliferation, and greatly enhance the absorption and utilization of calcium. Combining with calcium, it can effectively increase human bone density and bone length of children and adolescents.

　　CBP is made from bovine colostrum through sterilization, degreasing, centrifugal separation, ultrafiltration and other processes. Scientific research shows that CBP is an active protein with a molecular weight of only 30 kDa, which can directly act on bone cells, promote the proliferation of osteoblasts and greatly enhance the absorption and utilization of calcium. Therefore, CBP can inject new energy into bone health, and this mechanism is also called "CBP bone energy".

　　It is reported that in August 2021, the College of Food Science and Engineering of South China University of Technology and Peizhi Health Center organized a "90-day CBP Bone Energy Experience Program", in which 31 subjects including faculty and staff of South China University of Technology participated in the test. The test and statistical results show that about 90% of the subjects’ bone mass has been improved or maintained in good condition, and the remarkable effect accounts for about 65%.

　　Speaking of the legend that "milk contains hormones, which are harmful to health for adults and precocious puberty for children", Lou Wenyong also said that this statement exaggerated the influence of hormones in milk on people. "Growth hormone is a kind of protein secreted by animals’ brains. Almost all animal milk contains a small amount of hormones to promote the growth of animals. Undoubtedly, as long as it is milk squeezed by healthy cows, its hormones are very low and meet safety standards, so don’t worry too much. " He said that milk is rich in nutrients such as calcium, vitamins, protein and trace amounts of bone growth factors CBP, lactoferrin, immunoglobulin, etc. It is self-evident that drinking milk for a long time is beneficial to health. "Humans have been drinking milk for thousands of years. Facts have proved that children who drink milk for a long time are generally taller than children who don’t drink milk. Adults who insist on drinking milk are also healthier. That’s why ‘ A glass of milk a day makes a nation strong ’ The statement. "

　　But he also stressed that it is impossible to effectively supplement CBP by drinking milk alone. He said that the content of CBP in ordinary milk is only 0.15% (0.015‰ ), the content in bovine colostrum is only four ten thousandths (0.4‰ ), the content is extremely low, very rare. Therefore, it is necessary to extract CBP from milk and bovine colostrum and add it to related products to realize an efficient and rapid CBP supplement method. At present, CBP can be added to nutritious food alone, and it can also be combined with other nutrients to play a better role. For example, the DKC gold combined bone energy composed of CBP, vitamin D and vitamin K2, or immunoglobulin IgG, intelligent nutrition phosphatidylserine PS, etc.

　　In addition, Lou Wenyong also suggested that developing good living habits, such as eating more foods with high calcium content, ensuring adequate sleep, getting more sunshine, and appropriately increasing exercise load, will make the effect of CBP on improving bone health more obvious.