Overnight water, thousands of boiling water, hard water...
World Water Day "rehabilitates" these waters
March 22 is World Water Day.
Water is the source of life, we have to consume a lot of water every day, but do you really know how to drink water?
Nowadays, there are many opinions about drinking water on the Internet, such as drinking overnight water can cause cancer, drinking 4 liters of water a day will cause poisoning, drinking water with a lot of limescale is easy to get stones... On the occasion of World Water Day, the life version sorted out the more popular online The four major rumors of drinking water, let you drink water clearly.
Drinking overnight water and thousand boiling water cause cancer?
The truth: the nitrite contained in it does not exceed the standard value
"Drinking overnight water and thousands of boiling water cause cancer" has been rampant in WeChat Moments for many years, and many elders are convinced of this. The rumor claims that overnight plain water and water that have been boiled many times (commonly known as "thousand boiling water") contain Nitrite, this substance is a carcinogen.
Is it really the truth?
Fan Zhihong, an associate professor at the School of Food Science and Nutritional Engineering of China Agricultural University, said that the carcinogenic substance that people are worried about—nitrite must be produced in substances that contain nitrates, while ordinary drinking water contains only minerals and trace elements. , Or nothing, in this case carcinogens will not appear out of thin air.
As long as the source of the water meets the standards, in theory, no matter how much water is burned, it will not produce carcinogens.
"You don't have to worry about the excessive nitrite in the overnight water and the thousand boiling water." Ruan Guangfeng, director of the science and technology department of the Kexin Food and Nutrition Information Exchange Center, said in an interview with a reporter from the Science and Technology Daily. The overnight water and the thousand boiling water are often deducted." The hat of “excess nitrite” is further related to “carcinogenic”.
The truth is that even if the water is repeatedly boiled 20 times, the nitrite content will not reach 3% of the upper limit required by the national drinking water standard.
Experiments also proved that the nitrite content of water overnight (or even several nights) is far from the over-standard value.
In addition, Ruan Guangfeng specially reminded that although overnight plain water is not harmful to the human body, drinking overnight tea is indeed bad for health.
"This is mainly because the water after tea soaking will produce amino acids and other substances, which is easy to breed microorganisms over time." He said.
Drinking 4 liters of water a day is poisonous?
Truth: No need to worry as long as it's not a short-term drink
cold?
Drink more water!
headache?
Drink more water!
in bad mood?
Drink plenty of water...In the eyes of many people, drinking plenty of water seems to be the "perfect solution" to solve all problems.
However, there are rumors on the Internet that the World Health Organization expert Bruce Gordon said that drinking more than 4 liters of water a day may be poisoned, and even cause brain function damage, and in severe cases may be life-threatening.
Although the World Health Organization claimed that this view was a misunderstanding and promptly refuted the rumor, many people still faintly worry about whether drinking more water will affect their health?
The amount of body fluid of a normal adult accounts for about 60% of body weight. There are two main ways for humans to obtain water: one is to ingest from food, about 700 ml to 2000 ml per day, and they are mainly absorbed by the gastrointestinal tract; the other is Every day the human body produces about 300 ml of water during metabolism.
Most of this water will form urine and be excreted through the human urinary system, and a small amount will be excreted through the lungs or skin in the form of water vapor or sweat.
Relevant experts said that there is indeed the concept of "water intoxication" in medicine. When the human body's intake of water greatly exceeds the amount of excretion, water is retained in the body, which causes a decrease in plasma osmotic pressure and an increase in circulating blood volume, which may cause water intoxication. It is also known as dilutional hyponatremia. According to the severity of the disease, the disease can be divided into acute water intoxication and chronic water intoxication.
However, water intoxication is actually rare in clinical practice. Even if the patient does experience water intoxication, it is mostly not only due to excessive drinking, but because the patient has other problems or received some inappropriate treatment operations.
For example, the patient itself has kidney disease, combined with cardiac insufficiency, drinking too much water at one time after exercise, and too much iatrogenic infusion, which may lead to water intoxication.
In fact, the kidneys of healthy people are very adaptable and will not "strike" just because they drink more water.
"As long as it is not drunk in a short period of time, it will not affect your health." Ruan Guangfeng said.
Is drinking water with more limescale more likely to get stones?
Truth: Hard water tastes bad, but it won't harm your health
After the kettle is used for a long time, thick scale will form on the inner wall.
It is widely rumored on the Internet that long-term drinking of hard water with a lot of limescale after boiling will increase the risk of stone disease.
So is this statement true or false?
Ruan Guangfeng said that the formation of scale is related to the hardness of the water. The water in the north of my country is more "hard" than that in the south, mainly because it contains more calcium and magnesium ions (such water is also called hard water).
Calcium ions and magnesium ions contained in the water will become insoluble mineral salts when heated at high temperatures, and precipitate in the kettle, thus forming scale.
"However, there is currently no conclusive evidence that drinking hard water can cause stones or other health problems. On the contrary, if people drink less water and eat more, their urinary system is more likely to have stones." Ruan Guangfeng said.
"Drinking hard water can cause stones. It is completely a rumor. Although hard water tastes bad, it is harmless to the human body. The calcium and magnesium contained in it are both essential elements for the human body. And most people's calcium and magnesium intakes are now Low. In this sense, drinking water with high hardness can also replenish some minerals to the human body. Of course, the mineral content in hard water is far from what the human body needs in daily life. The right way to supplement minerals is a balanced diet. ." Ruan Guangfeng said.
Drinking purified water will cause osteoporosis?
Truth: The main cause of calcium loss is age, hormone level, etc.
There are rumors that purified water is also called poor water. When it is processed, the "life ions" that nourish the human body are also removed. The more you drink this water, the more acidic your body fluid becomes.
Moreover, purified water will bring a large number of trace elements in the body to the body, so that people will suffer from osteoporosis and rickets.
So, are these claims true?
Purified water is water prepared by reverse osmosis or distillation, with most impurities removed.
Lu Qing, an associate professor at the School of Public Health of Tongji Medical College of Huazhong University of Science and Technology, said in an interview with the media that pure water does not contain any trace elements, but after treatment, the essential mineral elements such as calcium, magnesium, potassium, and sodium are significantly reduced.
"The normal pH of human body fluids is between 7.35 and 7.45. Although the body is constantly producing and ingesting substances with different pH levels, the pH of body fluids does not change significantly. Purified water is neutral or weakly acidic and passes through human gastric juice. Reconciliation and intestinal absorption will not change the pH of organs or other tissues. Therefore, for the human body, drinking pure water will not make body fluids more and more acidic.” Lu Qing said.
Regarding the statement that long-term drinking of purified water will cause osteoporosis and rickets, Zhong Kai, deputy director of Kexin Food and Nutrition Information Exchange Center, said that people holding this view do not understand the physiological conditions of the human body.
An adult weighing 60 kilograms has a body fluid weight of about 36 to 42 kilograms, and his daily drinking volume usually does not exceed 2 liters.
This amount of drinking water has no effect on the calcium ion concentration in the body. The main factors leading to the loss of calcium in the body are age, hormone levels and dietary intake.
On the other hand, the causes of rickets are insufficient vitamin D intake, low calcium content in the body, and insufficient sunlight exposure.
The main way for the human body to take in elements such as calcium and magnesium is daily diet, not drinking water.
Therefore, drinking pure water is not related to the occurrence of rickets.
Further reading
Drinking water like this is healthier
What is the most scientific way to drink water?
What kind of water should we drink?
Ruan Guangfeng gave the following suggestions:
First of all, drink moderate amounts of water.
The "Chinese Residents' Nutritional Dietary Guidelines (2016 Edition)" recommends that adult men drink 1700 ml of water per day and adult women drink 1500 ml of water per day.
Of course, this amount is not fixed, you can adjust it according to your own situation.
For example, if you exercise more and sweat a lot that day, you can drink more; the air in the north is dry, and you can drink more water; if you enter the hot summer, you need to increase the amount of drinking water according to the intensity of labor and the degree of sweating.
Many people want to ask, how many glasses should I drink a day?
There has always been a saying that people are advised to drink 8 glasses of water a day.
In fact, the specific number of cups to drink depends on the capacity of the cup used.
Our daily cup capacity is 200 ml to 300 ml, so it is usually 6 cups to 8 cups.
Of course, the capacity of each person's cup is different, and the best way is to simply convert it according to the capacity of your own cup, and you don't need to be exacting to reach 8 cups.
Secondly, drink a small amount of water many times.
Ruan Guangfeng said, do not wait until you are thirsty to drink water, you should consciously take the initiative to drink, and ensure a small amount for many times.
In addition, some patients with chronic diseases should pay attention to drinking plenty of water, such as hyperuricemia, gout, and diabetes. Drinking plenty of water can alleviate the symptoms to a certain extent.