Drinking water boiled by an electric kettle for a long time may lead to excessive heavy metals? 2 points of advice, please listen to it
Mr. Zhao, who lives in Guangzhou, bought a kettle with 1 yuan in the supermarket not long ago, but he always felt that the boiled water had a burnt smell . "Bar?
Recently, there have been many claims on the Internet that "electric kettles will precipitate heavy metals (manganese), and drinking such water for a long time will not only cause poisoning, but may also cause cancer." Is it safe to boil water in an electric kettle? Will drinking boiled water repeatedly for a long time be harmful to the human body?
1. What happens to your body when you drink water boiled by an electric kettle?
Stainless steel electric kettles are almost one of the must-have small appliances in every household, but it is said that some businesses use cheap high-manganese steel to make electric kettles in order to save costs. People who drink this kind of electric kettle for a long time may be poisoned. . real or fake?
First of all, manganese is one of the essential trace elements for the human body. It is a component of bones, coagulation factors, sex hormones, connective tissue, etc. It is also indispensable for fat metabolism, calcium absorption, and blood sugar regulation.
But like many minerals, excess manganese inhibits iron absorption, and chronic excess can affect nervous system function .
In China, 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 China's Fourth Nutrition Survey, Chinese residents can get about 6.8 mg of manganese from their diets every day , so it is at a safe level every day, so there is no need to worry too much.
In fact, the absorption rate of manganese in the gastrointestinal tract of the human body is not high, and the possibility of manganese poisoning caused by food intake is very low . On the contrary, it is more likely to cause manganese poisoning through breathing.
What's more, the melting point of manganese is above 1200 ℃, and the temperature of household electric kettle will not exceed 100 ℃ during daily use , so boiling water will basically not cause manganese dissolution. Even if it is really dissolved, it must reach the tolerance value or above before it may cause poisoning.
In fact, high manganese steel is not as "poisonous" as rumored. As long as it is a container used for making food that has been inspected by the state, it meets the strict restrictions . However, if you want to use it with confidence, there are 2 suggestions:
- purchase through formal channels
When purchasing, it can be purchased in formal malls, such as large electrical appliances with "three guarantees service", and well-known e-commerce platforms.
- Look at the inner tank to choose the material
Check whether the inner tank of the electric kettle has these two numbers - 304, 316. 304 stainless steel is food-grade stainless steel, which has strong corrosion resistance; 316 is generally used in high-end fields such as aerospace or food machinery, and has better stability. But the price is too expensive.
2. Thousands of boiling water and overnight water cannot be drunk, and drinking it will cause cancer?
Water is an indispensable fountain of life for human beings, but with the improvement of people's health awareness, some "water" has also been accused of "carcinogenic".
1. "Thousands of Boiling Water"
That is, water that has been boiled for a long time (repeatedly boiled). Rumors say that in the process of repeatedly boiling water, due to high temperature and lack of oxygen, nitrite will be produced, which may cause cancer .
In this regard, researchers from Harbin Institute of Technology conducted an experiment: by sampling raw water and water that was boiled once to 5 times, and measured nitrite, nitrate and other substances, it was found that the content did not occur. 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 if the water is left standing for too long, nitrite will also be produced. According to national regulations, the standard of nitrite in drinking water is 1 microgram/ml. Generally, overnight water does not exceed this number, so it can be safely consumed.
It's just that during the placement process, because the lid is not covered, insects and dust may fall off. If there is no water sealed with the lid, try not to drink it .
The real water that may cause cancer is actually water above 65 degrees Celsius . The surface of the human mouth and esophagus is covered with delicate and fragile mucous membranes, which are very sensitive to temperature. Once the temperature exceeds 65 °C, there is a danger of scalding.
Occasionally scalded, the mucous membrane can repair itself. Repeated scalding will lead to more and more "atypical" cells. Even if there is no cancer, it will also be troubled by oral ulcers and esophageal ulcers.
3. Mineral water VS purified water, which one is better to drink?
Not all bottled water is mineral water. In the "General Principles of National Standard Beverages", bottled water is divided into mineral water, purified water and other drinking water . Which water is better, mineral water or pure water?
In terms of composition, mineral water refers to containing a certain amount of natural mineral salts (such as calcium, potassium, magnesium, strontium, metasilicic acid, etc.), while pure water is "water as its name suggests", basically removing all minerals and High-purity water with other impurities and bacteria .
Maybe in the eyes of some people, drinking mineral water can add some minerals, while pure water is "filtered" and has no nutrients.
However, for the human body, no matter what water it is, it only plays a role in replenishing water. Even mineral water contains very small amounts of minerals. If you want to supplement trace elements, it is better to use other foods, which may be more reliable than drinking water.
Drinking water every day is more important than choosing what water to drink.
The "water" here refers to plain water and cannot be replaced with sugar-sweetened beverages . Sugar-sweetened beverages with high concentration and high osmotic pressure will make you thirstier when you drink them; and with their own calories, you may get fatter and more expensive than water.
References:
[1] "Electric kettle makes people stupid? Will "high manganese steel" damage memory? 》. Nutshell.2016-03-24
[2] "The surface of our mouth and esophagus is covered with delicate and fragile mucous membranes". People's Network Science. 2018-06-26
[3] "Thousands of boiling water and overnight water cause cancer? Is more expensive water better? The truth about drinking water is unexpected". Tencent Medical Dictionary. 2019-09-24
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