1. The concept of overnight tea is difficult to distinguish-overnight tea does not cause cancer.
Tea brewed in the morning is very common to drink in the afternoon. Tea made in the middle of the night after work and tea drunk after getting up in the morning will not change more than during the day. If anything, the temperature is high during the day, and the tea may change greatly.
2. What will happen if the tea leaves are kept for a long time? . . . . How to drink tea is the healthiest
The research shows that the main change is that tea polyphenols are further oxidized and the color is deepened. A cup of clear green tea, especially at high temperature for a long time, will lose its green color and increase its yellow color. This is the yellow-red and reddish-brown oxidation products formed by the oxidation of tea polyphenols in tea, mainly theaflavins, thearubigins, theabrownins and so on. These products are non-toxic and will not cause harm to human body.
3. Some people speculate that after tea leaves overnight, nitrosamines, a carcinogen, will be produced-tea products will be healthy.
First of all, it must be affirmed that even nitrosamines in tea are negligible. Many foods we eat every day, such as bread, vegetables, pickles, salted fish, bacon, etc., all contain nitrosamines, and the content is much higher than that in tea. But I haven't seen anyone who doesn't eat. The content of nitrosamines in each kilogram of meat products is 4 ~ 50 micrograms. Isn't it terrible? Actually, it is not, because the human body itself has the function of decomposing nitrosamines.
Moreover, nitrosamines can cause cancer only when absorbed per kilogram of body weight 100 ~ 2000 mg, and they are taken in large quantities all year round. Generally, normal food intake will not cause such great harm, and the amount of tea is even more insignificant compared with food intake. If people easily "bow their heads" to these trace amounts of nitrosamines, how can they be called "the spirit of everything"?
So it is unreasonable to worry that drinking tea will bring nitrosamines harm to cancer.
In addition, studies show that tea is rich in tea polyphenols and vitamin C, which is a natural inhibitor of nitrosamines. Therefore, drinking tea can also eliminate the harm caused by other foods containing nitrosamines. Tea is rich in tea polyphenols, which can inhibit lipid peroxidation by scavenging carcinogens such as oxygen free radicals. Vitamins C and E in tea also have an auxiliary anti-cancer effect.
After staying overnight for a long time, most of the vitamins are lost, and the protein and sugar in the tea soup will become nutrients for bacteria and mold. So people usually think that overnight tea can't be drunk. In fact, the non-deteriorating overnight tea can not only be drunk, but also has the following health care functions:
Anti-cancer and anti-oxidation: Tea leaves will turn reddish brown after a long time, which is due to the oxidation of tea polyphenols into reddish brown tea pigments. Studies have shown that tea polyphenols and tea pigments have strong anti-cancer and anti-oxidation effects. Although the content of vitamin C in overnight tea is greatly reduced, it still has disease resistance.
Hemostasis: Overnight tea is rich in acid, which can prevent capillary bleeding. If you suffer from stomatitis, carbuncle with red tongue, eczema, gingival bleeding, etc. You can rinse your mouth with overnight tea. It can also be used for bathing sores, abscesses and skin bleeding.
Mingmu: Tea polyphenols in overnight tea have antibacterial and anti-inflammatory effects. If red silk appears in your eyes, you can wash it with overnight tea several times a day.
Stop itching: Wash your hair or wipe your body with warm overnight tea. Fluorine in tea can quickly relieve itching and prevent eczema.
Hair growth: Washing your hair with overnight tea also has the effect of hair growth and dandruff removal. If the eyebrows are too thin, you can brush them with a brush every night. Over time, your eyebrows naturally become thick and bright.
Fixing teeth and cleaning teeth: after fluoride in tea calcifies with enamel of teeth, it will enhance the resistance to acidic substances and reduce the occurrence of tooth decay; Fluorine can also eliminate dental plaque, and it is best to rinse your mouth with tea two or three minutes after meals.
In addition to bad breath: tea contains essential oil and smells delicious. Before and after brushing your teeth in the morning or after meals, gargle a few mouthfuls of overnight tea, which can make your breath fresh, and often gargle with tea can eliminate bad breath.
Sun protection: If the skin is sunburned by the sun, you can gently wipe it with a towel dipped in overnight tea. Because tannic acid has astringent effect on skin, flavonoids in tea also have anti-radiation effect.
Get rid of fishy smell and get tired: overnight tea also has a strong effect of getting rid of fishy smell and getting tired. Washing hands after eating shrimps and crabs is refreshing.
The use of overnight tea should be based on continuous deterioration (deterioration). In summer, when the temperature is high, tea leaves are prone to rancidity and taste bad. If you leave it for more than 24 hours, you'd better not drink it, otherwise it will cause diarrhea.
Overnight tea can also lengthen eyelashes.