This is a "drinking poem" written by Swallow in the TV series "Princess Pearl", which was brushed by a doctor in a small video. It's interesting. Although it is a joke of the characters in the play, it shows the importance of water to the human body to some extent.
Water accounts for about 70% of body weight and is an important part of human metabolism, so people usually call it "the source of life".
Traditional Chinese medicine believes that water can nourish yin, while hot water has the function of warming and nourishing yang in the soil, which can promote blood circulation and human digestion and absorption; Western medicine emphasizes that boiled water can sterilize and is beneficial to human body. Therefore, people in China have always had the habit of "drinking hot water".
There are many tools for boiling water in our daily life, and electric kettle is very common and convenient, which has an important influence on our life.
However, with more and more people using electric kettles, there is a rumor that drinking water boiled with electric hot water for a long time is harmful to human body and will cause cancer. Many friends around me have told me the same thing. Is that really the case? What the hell is going on? Let the doctor take you to know more about it.
I looked up a lot of information and found that this statement mainly comes from three points: 1) boiling water with an electric kettle will release a lot of heavy metals, which are toxic and even carcinogenic; 2) Repeatedly boiling water with an electric kettle will produce a large amount of nitrite in the water, which will cause cancer; 3) Long-term boiling of electric kettle will produce a lot of scale, and long-term drinking will lead to stones, which is harmful to human body. Let's explain these three points one by one.
The saying that "the heavy metals in the water boiled by electric kettle exceed the standard" has been circulating for a long time. A friend told me before, and he explained the reason to me, saying that the material of electric kettle contains lead, manganese, nickel and other elements, all of which are heavy metals, which will affect the human nervous system, lead to nervous system disorder and cause cancer.
Actually, this statement is not rigorous. This situation is basically due to the use of inferior electric kettles, which will not happen in normal use.
Some brands of inferior and low-priced electric kettles are probably made of recycled inferior stainless steel, basically high manganese steel, which is widely used in industry and belongs to non-edible high manganese steel. The electric kettle made of this material will do harm to human body if it is boiled for a long time. However, this will not happen to most electric kettles on the market.
Qingdao Laoshan District Center for Disease Control and Prevention once conducted an experiment with the topic "Whether boiling water with electric kettle for a long time is harmful to human body".
CDC staff bought 14 electric kettles of different brands, prices and materials in the market, and randomly selected 30 electric kettles used by residents to participate in the boiling water testing.
Finally, it was found through testing that the metal elements such as iron and nickel in the water did not change obviously before, after and after boiling 12 hours, which means that most electric kettles on the market are qualified, and as long as they are qualified drinking water, most electric kettles on the market can be used safely.
Since the electric kettle on the market is boiling water, it is difficult to analyze heavy metals. Can repeated boiling of water in electric kettle cause cancer?
The origin of this statement is that with the repeated boiling of water, the content of volatile substances such as magnesium and nitrite in water will increase, and long-term intake of nitrite will react with gastric acid to generate nitrosamines, which is easy to cause cancer.
For this statement, I want to say that it is too much. First of all, it is certain that the nitrite in the water is not brought by the kettle, but may be the water itself. This is because nitrogen in the air is dissolved in tap water, which is produced by the combination of nitrogen and cations in water during the process of boiling water, but this content is extremely low and will not cause harm to the body.
Moreover, the content of nitrite in water will decrease after repeated boiling. After repeated boiling, the nitrite content in water will decrease. This is because water is at a high temperature during boiling, and the oxygen content in water is extremely low. Nitrite ions in water are usually reduced, and nitrite ions will be reduced to nitrate ions, thus reducing the content of nitrite.
Take bottled pure water as an example. Even after repeated boiling for 200 times, there are only 3-4 micrograms of nitrous acid per liter of bottled water. If you want to reach the toxic dose, you need to drink at least 20 tons of "boiled water". So, don't worry at all. Otherwise, in real life, we don't eat hot pot or soup, which would be a lot less fun.
There are different opinions about this statement. Many people think that boiling water in an electric kettle will produce a lot of scale. Drinking the water boiled in this kettle for a long time will cause the minerals in the scale to precipitate in the body and form stones, which is harmful to the body.
In fact, scale itself is harmless and has no causal relationship with stones.
The main components of scale are calcium carbonate and magnesium hydroxide. Water contains calcium and magnesium ions and bicarbonate ions, which can be combined to form calcium and magnesium bicarbonate, while bicarbonate is very unstable and will be converted into calcium carbonate and magnesium hydroxide respectively at high temperature. These two substances are insoluble in water and will form scale.
The formation of scale is related to water quality, in which calcium and magnesium ions belong to minerals and are also needed by human body. The stones in human body are mainly oxalic acid stones and uric acid stones, which are pathological and have nothing to do with scale.
When we drink water, even if we drink the scale into our stomachs, we don't have to worry at all, because gastric acid will decompose this scale into calcium and magnesium ions, which are absorbed by the human body, and calcium and magnesium elements are also essential trace elements for the human body.
However, there is a saying in China that "going too far is not enough". Nothing is absolute. Although scale is harmless, it will continue to breed bacteria. After all, it is not hygienic. Therefore, we'd better clean the scale in the pot regularly.
Having said that, someone will definitely ask, how to choose an electric kettle? Is there anything to pay attention to when boiling water? Now let me answer your question.
First of all, it is best to choose some well-known and professional manufacturers of small household appliances to buy electric kettles. These manufacturers are generally guaranteed in terms of materials, workmanship, temperature control and insulation, and electricity safety.
Secondly, when buying an electric kettle, pay attention to the material of the inner container. Be sure to choose food grade 304 stainless steel. 304 stainless steel conforms to People's Republic of China (PRC) and National Standards/Hygienic Standards for Stainless Steel Tableware Containers, and the nickel content is only 8%. It belongs to food-grade stainless steel, and it will not produce harmful substances when boiling water, so it is very safe to use.
In addition, there is a very important point: safety. After all, the electric kettle works with electricity, so this is also very important. The bottom of the electric kettle connected to the power supply has an electrode coating, which is generally plated with copper, silver and gold. The effect of gold plating is similar to silver plating, and the cost of gold plating is too high, which is almost unnecessary. The silver-plated electric kettle has good conductivity and relatively high safety, which can effectively avoid the ignition problem, but the cost is high.
Finally, there are some precautions for boiling water with an electric kettle. 1) There is usually the highest water level line inside the electric kettle, that is to say, the water level line cannot exceed the highest point when boiling water, otherwise the boiled water will overflow outside the kettle, which may lead to a short circuit at the power connection of the base and cause potential safety hazards. 2) Be sure to add water before electrifying to keep the kettle dry, so as to avoid the safety problem of hot water kettle caused by steam. 3) Try not to use it with other high-power appliances. The electric kettle itself has higher power. If it is used with high-power electrical appliances, it is easy to burn out the circuit and cause potential safety hazards.
The climate in spring is complicated and changeable, especially in the north, which is dry and often windy. The human body loses water easily and its resistance drops, which leads to colds and many chronic diseases. This requires timely "replenishment", and this replenishment is also particular.
Get up early with a cup of warm water. It can replenish the water lost in a night's sleep in time, especially in the changeable spring. A cup of warm water in the morning can promote blood circulation and clean the stomach, which has a good health care effect.
Never wait for thirst before drinking water. When you feel thirsty, it means that your body is in a state of water shortage, which is not conducive to your health. Especially in windy spring, you should replenish water in time and drink no less than 6 glasses of water every day.
Then you need to drink water slowly, not at once. Slow drinking can moisten the mouth and throat, or it can slowly flow into the human body and be absorbed by the human body; Drinking water with a big mouth will dilute gastric juice, reduce the digestive function of the stomach, dilute blood and increase the burden on the heart, so it is best to drink slowly with a small mouth.
We live in an Internet age and have an extremely developed information network. We can learn information and news from all walks of life through the Internet, and we can also screen out information and topics that are closely related to us.
But the information on the Internet is ever-changing, and it will be filled with all kinds of comments. What I want to say is that you must not blindly believe these information and comments, and don't blindly follow the trend. You must understand the relevant situation through multiple channels, make comprehensive analysis and judgment, and look at the problem from a rational perspective to avoid some false information from having a negative impact on yourself.