In winter, the weather is dry, and the three-word motto of health is time for everyone:
Drinking water, although it is a very common thing in life, is sometimes quite exquisite.
For example, one of the sending propositions in love: don't say "drink more hot water" to girls, otherwise they may blow up in minutes.
Single dogs may scoff at this, this belongs to the "metaphysics of love", a single dog that emits a fragrance does this?
Koko ~ This is also applicable to single dogs. Why? Because hot water is easy -
What a hot mouth!
Don't look at this time hot mouth is not much big, keep burning mouth may cause cancer.
This is not a rumor, at present, hot drinks above 65 °C are listed as IIA carcinogens (most likely carcinogenic) by the International Agency for Research on Cancer (IARC). [1]
This is because hot water above 65 ° C is easy to burn the esophagus, and mucosal cells will proliferate and repair after thermal damage, but if they are repeatedly burned, the mucous membrane may be mismatched and mutated in the continuous repair, and normal tissues may have abnormal changes, resulting in cancer.
Source: Tencent Medical Dictionary Medical Illustration
Of course, as long as you don't drink it often, it's still safe. For ordinary people, the exquisiteness of drinking water may be more:
Is the more expensive the water, the better?
Can mineral water be drunk for a long time?
Is mineral water more nutritious than pure water?
Come and go, there are so many problems with drinking water, let's have a good chat.
In essence, both of these are boiled water, thousand boiling water is repeated boiling water, overnight water storage time is long, there are rumors that these water nitrites are very high, and then buckled on the "poisoning" and "carcinogenic" hat.
Indeed, nitrites are toxic to the human body. After nitrite enters the human body, it can be converted into nitrosamines in the stomach, and nitrosamines are transported to the target organs of the body, which is to do things - as long as conditions permit, carcinogenic, teratogenic, mutagenic, it can do. [2—6]
The rumor-mongers couldn't help but take the case: You see, I'll just say it will cause cancer!
As we all said just now, nitrites are not unconditionally pathogenic. Talk about toxicity without dose, either stupid or bad! What is the real situation? Experiments have shown that:
1. Unblanched tap water with a nitrite content of 0.007mg/L
2. Boil once, nitrite content of 0.021 mg/L
3. Boil 20 times with 0.038 mg/L nitrite content[7]
In the domestic drinking water sanitation standards in the mainland, the nitrite content is specified as ≤1mg/L. [8] Therefore, numerically, even if the water is boiled 20 times, it is far from the level of sanitation and can be safely drunk. Theoretically, unless you boil water 200 times repeatedly, there may be a risk of carcinogenicity, but who would be bored enough to boil water 200 times? So expensive electricity, there is a mine at home?
So, what about the boiled overnight water?
It can be seen that even if a cup of boiled water is placed at room temperature for 72 hours, the nitrite content is only 0.3455 mg/L, which still meets the sanitary standards for drinking water. [9] Also, after 3 days of water, is there anyone else who drinks it?
So if you have to say that overnight water causes cancer, isn't that just a show to let it carry the pot?
The problem of overnight water is the length of storage time, the water with the open lid is left for too long, although the nitrite content will not exceed the standard, but it may be contaminated by small bugs and dust.
Therefore, boiling water is still drunk as soon as possible, or stored in a sealed container, especially in the summer temperature is too high, to avoid excessive growth of bacteria.
The water sold in supermarkets is nothing more than these: purified water, mineral water, mineral water. What is the difference between them? Is the more expensive the water, the better?
Let's first look at the difference between these types of water:
Mineral water: contains a certain amount of natural mineral salts (such as calcium, potassium, magnesium, strontium, metasilicic acid, etc.), and its chemical composition pattern is the same as that of natural mineral water.
Purified water: Water, as the name suggests, has a very low mineral content and is made through some food processing methods (such as ion exchange, reverse osmosis, distillation, etc.).
Mineral water: It is to add mineral salts to pure water.
Seeing this, some people feel that mineral water contains a variety of natural minerals, which are obviously more nutritious than pure water. Some people even forcefully released "rumors": pure water belongs to "poor water", almost no minerals, long-term drinking will lead to the lack of trace elements in the body, affecting health.
Water red is not much, just because of the properties of pure water, there has also been a large wave of black powder, they have made remarks: long-term drinking pure water will be deficient in calcium, drinking pure water is harmful to health, mineral water is more nutritious than pure water...
In this regard, the water said that it could only hold itself and shiver, because whether it was pure water, mineral water, mineral water, for the human body, there is only one role: to replenish water.
Water is not the main source of any nutrients we supplement, whether there are minerals in the water or not, the impact on meeting the nutritional needs of the human body is negligible, and there is no nutritional value at all.
Compare the calcium content of our common mineral water and milk:
From the figure we can see that the calcium content of mineral water is ≥ 400 ug / 100 mL, for convenience, let's convert the unit: ≥ 4 mg /L, and the calcium content of a bottle of milk is 100 mg/100 ml.
The recommended daily intake of calcium for healthy adults is 800mg, so even if you drink 4L of water a day, you can only supplement calcium with 16mg, drinking a bottle of water is not as good as the calcium content of a mouthful of milk, how to say that drinking water calcium supplementation?
The same is true for other nutrients. Therefore, if you want to get supplementary body nutrition, you need to eat honestly and well, and eat a balanced diet.
Since the purpose of drinking water is so simple, and do not expect to rely on the minerals in the water to supplement human nutrition, the "black powder" statement is naturally not established, no matter which kind of water is drunk for a long time, it has no great impact on physical health, and there is no water that is more nutritious.
Therefore, when you encounter a person who advocates drinking a certain kind of water "long-term drinking is harmful to health" or a certain kind of water "long-term drinking has health benefits", it is recommended that you give him a caring look:
At this point, I believe that everyone will understand that drinking water to meet the needs of the human body is nothing more than two points: one is clean and hygienic, and the other is that the amount must be managed enough.
According to Chinese dietary guidelines, healthy adults need about 1500 to 1700 ml of daily water intake. According to the size of the usual cup (200 ml specifications), about 7 to 8 cups, so the conversion, the "8 cups of water per day" transmitted by the Internet also has a certain reason.
But this does not mean that it is "necessary" to drink 8 glasses of water in counts, drink a few sips from time to time in small quantities every day, and the urine of each urination is transparent or light yellow, which can avoid dehydration of the body.
If you are sweating a lot in the summer, exercising a lot, dry air or kidney stones, you can drink more water appropriately, and it is also possible to reach more than 2500 ml per day. In addition, it is best not to wait until thirsty before drinking water, especially in patients with a history of kidney stones.
It should be emphasized that we should avoid replacing drinking water with sugary drinks such as fruit juices, because sugary drinks have a large concentration and high osmotic pressure, but they will drink more and more thirsty; and with their own calories, they may drink more and more fat; the market price is more expensive than ordinary drinking water. So why bother?
bibliography
[1] IARC Monographs evaluate drinking coffee, maté, and very hot beverages
[YANG Zheng-hua,HAO De-jing,XU Miao-miao.Clinical observation of 80 cases of nitrite poisoning[J].Chinese Journal of Practical Medicine, 2011, Vol. 6, No. 5.
[3] Jin Shaohua, Xu Chunliang, Cui Jie, Anhui Province, 2010-2013 Nitrite Food Poisoning Analysis[J].Anhui Journal of Preventive Medicine, 2014, Vol. 20, No. 4.
Wang Lili,Xiao Liang,Cong Yunxia. Residue and control of nitrite in food[J].Chinese and foreign food industry, 2014.
Chen Changhong,Zhang Ke. Pollution and prevention of nitrates and nitrites in food[J]Modern Agricultural Science and Technology, No.7, 2013.
Yang Guiling. Analysis of the causes of food poisoning caused by nitrites[J].Food Safety Guide, 2017.
Wu F, Wang H, Shu J W, et al. Correlation between residual chlorine and nitrite content and heating conditions in tap water[J]. Journal of Food Safety and Quality Inspection, 2017(11):4458-4462.
[8] Sanitary Standard for Drinking Water (GB/T5750-2006)
Chen Ying,Xiao Yanjie,Liu Xiaolin. Changes in nitrite and nitrate content at different times after drinking water is boiled[J]. Journal of Jinzhou Medical University, 2018, Vol. 39, No. 6.
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