Does Pu'er tea cause cancer? Drinking tea can cause kidney stones? Do you believe these 5 rumors about tea?

As the ancestor of the beverage industry, tea is loved by Chinese people for its "fragrant, light, refreshing, thick and clear" taste, and has given rise to tea culture. "Half a cup of pure tea moistens an inch of the body, cultivates virtue, nourishes the nature, and purifies the soul" (Hu Bingyan's "Tea").

But in recent years, various rumors about "tea" have often circulated on the Internet. In order to find out the truth, let us find out the truth together this time.

Rumor 1: Drinking tea can help you sober up from a hangover?

We have all heard that drinking tea can sober you up and relieve hangovers. So, is this true?

In fact, drinking tea is not particularly helpful for sobering up. The most important substances in tea are antioxidants such as caffeine and tea polyphenols . They cannot promote the metabolism of alcohol into acetaldehyde and acetic acid , and are actually not helpful for sobering up. Moreover, the metabolites of alcohol are mainly excreted through the kidneys, but although theophylline in tea has a diuretic effect, it may also cause the undecomposed alcohol to enter the kidneys prematurely, thereby causing damage to the kidneys. In addition, if too much tea is added (strong tea), there will be too much caffeine , and the metabolism of caffeine in the body will be affected by alcohol, so that it accumulates more in the body . Drinking the same coffee may make the human body more excited. Therefore, if you want to fall asleep as soon as possible after drinking, adding tea will do more harm than good. In fact, many folk methods used to sober up do not have the effect of sobering up . They are just for some symptoms . After using them, people feel more comfortable and seem to have the effect of sobering up. But they do not really metabolize alcohol and excrete it from the body . If you want to reduce the discomfort of drinking and avoid drunkenness, the most effective way is to drink less or not drink alcohol as much as possible.

Rumor 2: Drinking Pu'er tea can cause cancer

The Pu'er tea we usually refer to is Pu'er cooked tea, which is made through artificial fermentation. In the early stage of fermentation, the microorganisms in the tea are mainly Aspergillus niger and Rhizopus , and in the later stage, Aspergillus glaucus, Penicillium and yeast appear, which are harmless to human health.

When we see "Aspergillus", we easily think of a carcinogen - aflatoxin . So, is there aflatoxin in Pu'er tea? Aspergillus is a common mold in nature, and not all aflatoxin produces toxins. Only Aspergillus with toxin-producing genes can produce toxins under suitable nutritional conditions and environments. During the fermentation process of Pu'er tea, the higher temperature and the dominant black Aspergillus not only have a certain inhibitory effect on the growth of Aspergillus, but also can produce biologically active enzymes that degrade aflatoxin B1. In addition, the caffeine and tannins rich in tea can also inhibit the production of aflatoxin . For raw materials with guaranteed quality, after good fermentation and correct storage methods, aflatoxin will not appear in the Pu'er cooked tea. When consumers buy Pu'er tea, they should not choose the following four situations.

1. Don’t choose Pu’er tea that is too cheap .

2. Do not choose Pu'er tea with water stains on the paper package or obvious mold on the tea cake .

3. Do not choose Pu'er tea with soft and rotten leaves, mottled colors , burnt leaves, or black and hard stems .

4. Do not choose Pu'er tea with turbid tea soup or moldy smell .

Myth 3: Drinking tea can cause kidney stones

Many people believe that tea is rich in oxalic acid , which can combine with calcium in the human body to form calcium oxalate . Most kidney stones are calcium oxalate stones , so drinking tea can easily lead to kidney stones .

However, there are many loopholes in this. Although the formation of kidney stones is related to the excessive intake and abnormal accumulation of oxalic acid, the oxalic acid content in different types of tea with different production processes is not the same. The oxalic acid content of green tea, oolong tea, etc. is lower than that of black tea. It is a generalization to simply say that "tea is rich in oxalic acid".

Experiments have proved through large-scale population surveys that the oxalic acid content in tea can form a very low risk of kidney stones . People who have the habit of drinking tea not only do not increase the incidence of kidney stones, but some can even slightly reduce the incidence . Many studies have confirmed the benefits of tea to the kidneys. For example, tea polyphenols in tea have a protective effect on oxalic acid and calcium oxalate crystal-induced damage to human proximal tubular epithelial cells. Tea polyphenols can effectively increase the activity of antioxidant enzymes in cells, inhibit lipid peroxidation, scavenge oxygen free radicals, reduce damage to renal tubular epithelial cells, and thus reduce the incidence of stones ; tea polysaccharides in tea can significantly improve the biochemical indicators of diabetic nephropathy mice during the onset of the disease ; catechin EGCG in tea can inhibit the formation of calcium oxalate kidney stones in the kidneys and has a significant protective effect on renal function; EGCG can reduce the body's peroxidation damage and reduce the risk of stone formation, etc.

However, this does not mean that everyone can drink tea freely . If you drink a lot of tea without washing it for a long time, or drink strong tea for a long time, the tannic acid, theobromine and other ingredients in the strong tea will promote the formation of stones. The correct way to drink tea is to drink it in moderation and lightly, and wash the tea before drinking to wash away about 80% of the oxalic acid in the tea leaves. It is currently recommended to drink about 5 to 12 grams of tea per day and 3 to 4 brews.

In short, people who drink tea occasionally do not have to worry about developing kidney stones . For people who are accustomed to drinking tea every day, if they are healthy and have no abnormalities in metabolism, the probability of developing kidney stones is also very small. The theory that "drinking tea causes kidney stones" is not scientific.

Rumor 4: Drinking lotus leaf tea can help you lose weight quickly

When we search for "lotus leaf tea", many articles and videos about using lotus leaf tea to lose weight will appear. In fact, lotus leaf tea for weight loss is not reliable.

First, after any substance enters the human body, whether it plays a beneficial physiological function or produces harmful toxic effects, it must reach a certain intake. At present, the scientific research on lotus leaf tea weight loss has not undergone rigorous and scientific human trials, and there is no report on how much human intake can lose weight. Therefore, it is impossible to achieve the weight loss function without talking about the dosage . Furthermore, after the tea leaves are brewed, the effective ingredients cannot be dissolved 100%, and the dosage of the effective ingredients will be reduced . Second, weight loss is one of the 27 functions of health foods in China. If it is claimed to be able to lose weight, there should be a health food logo, and the instructions should have the amount of consumption, health effects, etc. The absence of the above logos, reminders and approvals means that these products have not been scientifically evaluated to prove that they have a weight loss effect at the recommended dosage .

Third, losing weight requires consuming the energy in fat, which requires that energy consumption is greater than energy intake. Energy consumption includes three aspects: basal metabolism, physical activity, and the thermal effect of food. For a relatively stable human body, basal metabolism is basically constant. If the diet is relatively fixed, the thermal effect of food is also relatively constant, and the only thing that can be changed is physical activity. Therefore, to increase energy consumption, you mainly need to increase exercise, while to reduce energy intake, you need to adjust your diet. It is unrealistic to rely on drugs without changing your lifestyle to reduce energy intake and increase energy consumption .

Finally, it is recommended that when choosing weight loss products, you should choose products with health food logos and try not to pursue rapid weight loss.

Rumor 5: Can soaking overnight tea leaves in water make eyelashes grow longer?

Everyone loves beauty, and long eyelashes can add a bit of charm. In order to make their eyelashes longer, some people who love beauty look for various methods, even folk remedies, such as soaking overnight tea leaves in water to apply on eyelashes.

1. There are no hair growth products based on tea. "Tea as a drink originated from Shennong." Tea culture has a long history in China. Tea has the functions of calming the mind, clearing the head, improving eyesight, quenching thirst and promoting salivation . In addition, tea is also rich in a variety of proteins, amino acids, microorganisms and minerals . If you drink tea after brewing it, it will certainly be good for your body, but this is limited to drinking and tasting tea, not using tea water for eye application.

Tea contains a large amount of catecholamines and various vitamins , such as vitamin A and vitamin E. Some studies have reported that these substances in tea can promote hair growth. Animal studies have also shown that tea can promote hair growth in mice. But so far, there are no hair growth products based on tea .

2. Applying tea leaves to the eyes is risky

Pouring tea on gauze and applying it to the eyes is very risky . First, gauze and tea, especially overnight tea, are at risk of bacterial and fungal contamination , which can easily cause eyelid, corneal and conjunctival infections. Second, tea contains a lot of acidic and alkaline irritants , which can easily enter the eyes with long-term use, causing eye redness, pain and other discomfort, and even the risk of corneal perforation.

The growth of eyelashes depends on the hair follicle stem cells under the skin and their surrounding environment. The use of overnight tea has risks such as eye infection and has no clear effect, so it is not recommended.