Mr. Zhao, who lives in Guangzhou, recently bought a kettle in the supermarket with 1 yuan, but he always felt that the boiled water had a burnt smell, and they all said that there was no good product, and Mr. Zhao was worried that this would not be the legendary "poisonous kettle", right?
Recently, there have been many statements on the Internet that "electric kettles will precipitate heavy metals (manganese), and drinking such water for a long time will not only be poisoned, but may also cause cancer". Is it safe for an electric kettle to boil water? Will drinking water that is boiled repeatedly for a long time be harmful to the human body?
First, often drink the water boiled by the electric kettle, what will happen to the body?
Stainless steel electric kettle is almost one of the essential small appliances in the family, but there are sayings that some merchants use cheap high-manganese steel to make electric kettles in order to save costs, and people who have drunk this electric kettle for a long time may be poisoned. Really fake?
First of all, manganese is one of the essential trace elements of the human body, which is a component of bones, coagulation factors, sex hormones, connective tissues, etc., and is also indispensable for fat metabolism, calcium absorption, blood sugar regulation, etc.
But like many minerals, excessive amounts of manganese can inhibit iron absorption, and long-term excesses can also affect the function of the nervous system.
On the mainland, the recommended daily intake of manganese for an adult is at least 4.5 mg and should not exceed 11 mg at most. According to the results of the fourth nutrition survey of the mainland, the manganese that mainland residents can get from their diets is about 6.8 mg per day, so they are at a safe level every day and do not have to worry too much.
In fact, the absorption rate of manganese by the human gastrointestinal tract is not high, and the possibility of manganese poisoning caused by food intake is very low, but through breathing, it is more likely to cause manganese poisoning.
What's more, the melting point of manganese is above 1200 °C, and the temperature of the household electric kettle in the daily use process will not exceed 100 °C, so boiling water will basically not cause manganese to dissolve. Even if it is really dissolved, it must be above the tolerance value to cause poisoning.
In fact, high manganese steel is not as "poisonous" as rumored, as long as it is a container that has been inspected by the state for the manufacture of food, it meets strict restrictions, but if you want to use it with confidence, there are 2 suggestions:
- Formal channels of purchase
When purchasing, you can buy on regular shopping malls, such as large electrical appliances with "three guarantees of service" and well-known e-commerce platforms.
- Look at the liner to select the material
Check to see if the inner tank of the kettle has these 2 numbers - 304, 316. 304 stainless steel is a food grade stainless steel, with strong corrosion resistance; 316 is generally used in high-end fields such as aerospace or food machinery, with better stability, but the price is expensive.
Second, thousand boiling water, overnight water can not drink, drinking will cause cancer?
Water is an indispensable fountain of life for human beings, but in response to the improvement of people's health awareness, some "water" has also been crowned with the crime of "carcinogenicity".
1. "A Thousand Boiling Water"
That is, water that has been boiled for a long time (repeatedly). It is rumored that during the repeated boiling of water, due to high temperature and lack of oxygen, nitrites will be produced, which may cause cancer.
In this regard, researchers at Harbin Institute of Technology conducted an experiment: by sampling raw water, boiling water once to boiling 5 times, measuring nitrites, nitrates and other substances, the results found that the content did not change.
It can be seen that repeated heating of water does not lead to an increase in nitrite.
2. "Overnight Water"
Some people say that the water is left to rest for one night, too long, and it will also produce nitrite. According to national regulations, the nitrite standard of domestic drinking water is 1 microgram / ml, and the general overnight water will not exceed this number, which can be safely drunk.
However, during the placement process, because the lid is not covered, bugs and dust may fall, if there is no cup lid to seal the water stored, or try not to drink.
The water that can really cause cancer is actually water above 65 degrees Celsius. The surface of the human body's mouth and esophagus is covered with delicate and fragile mucous membranes, which are very sensitive to temperature and are at risk of developing burns once they exceed 65 ° C.
Occasional burns, mucous membranes can also repair themselves, repeated burns, will lead to more and more "atypical" cells, even if not cancer, will also be plagued by mouth ulcers, esophageal ulcers and so on.
Third, mineral water VS pure water, which is better to drink?
Not all bottled water is mineral water, and in the General Principles of National Standard Beverages, bottled water is divided into mineral water, purified water and other drinking water. Mineral water or pure water, which kind of water is better?
From the composition point of view, mineral water refers to high-purity water that contains a certain amount of natural mineral salts (such as calcium, potassium, magnesium, strontium, metasilicic acid, etc.), while pure water is "water as its name", basically removing all minerals and other impurities and bacteria.
Perhaps in the eyes of some people, drinking mineral water can also replenish some minerals, while pure water is "filtered" without a little nutrition.
However, for the human body, no matter what kind of water, it only plays a role in replenishing water. Even mineral water, which contains very small amounts of minerals, wants to supplement trace elements, it is better to pass through other foods, perhaps more reliable than drinking water.
It is more important to drink water every day than to choose what water to drink.
"Water" here refers to white water and cannot be replaced with sugary drinks. Sugary drinks have a large concentration, high osmotic pressure, the more they drink, the more thirsty they are; and with their own calories, they may drink more and more fat, and the price is more expensive than water, which is really a "pit daddy".
Resources:
[1] "Electric Kettle Makes People Stupid? Does "high manganese steel" damage memory? 》. Fruit shell.2016-03-24
[2] "Our oral and esophageal surfaces are covered with delicate and fragile mucous membranes". People's Daily Science.2018-06-26
[3] "Carcinogenic is caused by a thousand boiling water and overnight water?" The more expensive the water, the better? The Truth About Drinking Water Is Unexpected". Tencent Medical Code.2019-09-24
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