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What is the effect of drinking water overnight

A cup of water has a life span of only 16 person hours. Some people say that the water contains nitrite overnight, which can cause cancer. Can we drink the water overnight? Let's have a look with Xiaobian.

Can I drink tea overnight

Generally speaking, the tea soup obtained after tea brewing contains trace nitrite. With the extension of storage time, especially under the condition of no airtight preservation, the content of nitrite in the tea soup will continue to rise, which may be the result of large-scale growth and propagation of microorganisms.

However, it was found that the content of nitrate in thearia overnight was not much, far lower than the limit of 1 mg / L in the hygienic standard for drinking water (GB 5749-2006). For example:

In 2006, a study published in Anhui Agricultural Science showed that after tea was placed for 24 hours, the content of nitrite reached 2.17 times of the initial value, which was 0.130 mg / L.

In 2014, another study on the change of nitrite content in Pu'er tea soup showed that after 60 hours storage at 25 ℃, the nitrite content reached the maximum value, which was 2.061 times of the initial value, but only 0.251 mg / L.

Although nitrite itself is toxic, it is not a carcinogen. Under the action of gastric acid, the nitrosamines which will react with the protein decomposition products are carcinogens. Nitrosamines are recognized as class 2A carcinogens by the international agency for research on cancer, which means that human beings may have carcinogens.

That is to say, the content of nitrite in overnight tea is within the safe range. Even if we drink some, we don't need to worry too much about its carcinogenesis.

But we do not encourage regular drinking, especially those overnight tea which can not be sealed and refrigerated, because such tea is very vulnerable to pathogens, dust and other pollution, drinking is harmful to health.