Current location - Health Preservation Learning Network - Health preserving class - Two problems of green tea
Two problems of green tea
Refreshing: Caffeine

Green tea can prevent dental caries and remove bad breath.

Green tea contains fluorine, in which catechins can inhibit the action of cariogenic bacteria and reduce the occurrence of dental plaque and periodontitis. Tannic acid contained in tea has bactericidal effect, which can prevent food residues from breeding bacteria, so it can effectively prevent bad breath.

1. Green tea anti-aging

Antioxidants contained in green tea help to fight aging. Because in the process of human metabolism, if it is over-oxidized, it will produce a lot of free radicals, which are easy to age and cause cell damage. SOD (Superoxide Dismutase) is a kind of free radical scavenger, which can effectively remove excess free radicals and prevent the harm of free radicals to human body. Catechins in green tea can significantly improve SOD activity and scavenge free radicals.

2. Green tea is antibacterial

Studies have shown that catechins in green tea can inhibit some bacteria that cause human diseases without harming the proliferation of beneficial bacteria in the intestine, so green tea has the function of whole intestine. Studies have shown that tea polyphenols can eliminate excessive harmful free radicals in the body, regenerate efficient antioxidant substances such as α-VE, VC, GSH and SOD in the human body, thus protecting and repairing the antioxidant system, which has a significant effect on enhancing immunity, preventing cancer and preventing aging. Drinking green tea for a long time can reduce blood sugar, blood lipid and blood pressure, thus preventing cardiovascular and cerebrovascular diseases. The medical research team of Showa University in Japan diluted 1 ml tea polyphenols solution to 1 of the concentration of ordinary tea, and put it into 10000 highly toxic Escherichia coli 0- 157. Five hours later, all the bacteria died, leaving none.

3. Green tea lowers blood fat

Animal experiments made by scientists show that catechins in tea can reduce total cholesterol, free cholesterol, low-density lipoprotein cholesterol and triglycerides in plasma, and at the same time increase high-density lipoprotein cholesterol. Human experiments show that it can inhibit platelet aggregation and reduce the incidence of arteriosclerosis. Green tea contains flavonol, which has antioxidant effect, prevents thrombosis and platelet aggregation, and reduces cardiovascular diseases.

4. Green tea slimming and fat reduction

Green tea contains theophylline and caffeine, which can activate protein kinase and triglyceride lipolytic enzyme through multiple functions, reduce the accumulation of fat cells, and thus achieve the effect of losing weight.

5. Green tea can prevent dental caries and remove bad breath.

Green tea contains fluorine, in which catechins can inhibit the action of cariogenic bacteria and reduce the occurrence of dental plaque and periodontitis. Tannic acid contained in tea has bactericidal effect, which can prevent food residues from breeding bacteria, so it can effectively prevent bad breath.

6. Green tea can prevent cancer

Green tea can inhibit some cancers, but its principle is limited to the inference stage. Drinking more tea is bound to have a positive encouraging effect on preventing cancer.

7. Whitening and UV protection of green tea

Experts found in animal experiments that catechins in green tea can resist skin cancer caused by UV-B.

8. Green tea can improve indigestion.

The latest research conclusion of anti-cancer of American green tea

Recent research reports show that green tea can help improve indigestion, such as acute diarrhea caused by bacteria, and drinking a little green tea can alleviate the condition.

Scientists have done a lot of research on whether green tea can fight cancer. On June 5438+ 10, 2004, an American company applied to the FDA: in the sale of green tea, it can be publicized that "drinking 40 ounces of green tea every day can reduce the risk of some cancers." Although supported by scientific evidence, the evidence is not perfect. "They submitted 220 articles published in public academic journals to support such a statement.

The FDA responded to the application a year and a half later and explained in detail how the decision was made. In this nearly 10,000-word reply, they commented on 223 documents of different categories (in addition to the 220 submitted by the applicant, they also found 3 others). First of all, 65 literature reviews, 2 abstracts and 1 meta-analysis papers are not original research papers, which are considered to lack sufficient details for evaluation, so they cannot support the application; Secondly, 12 animal experiment and 12 in vitro study are considered to only provide the direction of further research and the "possible hypothesis" about the function of green tea, but cannot support the statement that "green tea has anti-cancer effect on people"; 92 epidemiological investigations were not aimed at "green tea", but at general "tea", so the evidence did not directly support the conclusion and was excluded; The remaining 39 studies are also epidemiological surveys-the reliability of this research method is much worse than that of clinical controlled studies. These 39 studies are aimed at various cancers, and the FDA evaluates them according to the targeted cancers. The conclusion is that most of the studies are flawed-some samples are small, some samples are not representative ... Finally, only three studies and two studies on female breast cancer and male prostate cancer are highly credible, but two of them are that green tea will not reduce the risk of breast cancer, and the other is that it will not reduce the risk of prostate cancer. The two studies with weak effects on breast cancer and prostate cancer did not appear any repeated studies, and no other similar or related studies were published. So the FDA finally concluded that green tea is "extremely unlikely" and has anti-cancer effect!

Matters needing attention in green tea health care

At present, green tea has become the most popular health care product. In particular, the overwhelming rendering effect of some advertisements and the endless stream of related beauty and health products with green tea as the main component make some people regard green tea as the best choice for skin care and fitness. In this regard, relevant experts remind the majority of female consumers not to blindly follow the trend. As a health care product, green tea is not harmful to health, but if it is made into products by various businesses together with other raw materials, we should pay attention to some details.

Green tea skin care products have good efficacy and limited validity.

Although the effect of green tea skin care products is good, there are still some considerations in choosing such products. In green tea, tea polyphenols are one of the main substances that play a role in skin care and beauty. This substance has antioxidant effect, and it can replenish water and tighten skin when used in combination with vitamins B and E. However, it should be noted that tea polyphenols, as the general name of phenolic substances or their derivatives, are easy to volatilize in the air and lose their antioxidant effect. Therefore, this kind of skin care products, especially facial masks, had better be the new tea products of that year.

Drink green tea to lose weight and prevent diseases, but drink it carefully during menstruation.

Green tea contains a certain amount of caffeine. When it coexists with tea polyphenols, it can prevent the function of caffeine in the stomach, avoid stimulating the secretion of gastric acid, and make the disadvantages of caffeine not play in the body, but promote the functions of the central nervous system, heart and liver. Moreover, the aromatic compounds in green tea can also dissolve fat and prevent fat from accumulating in the body. Caffeine can also promote the secretion of gastric juice, help digestion and fat elimination. However, it is best for women not to drink more alcohol during menstruation. Studies have shown that in addition to the normal iron loss of human body, women will also lose 18 ~ 2 1 mg of iron during each menstrual period. Drink more green tea during menstruation, and more tannic acid in green tea will combine with iron molecules in food, forming a large number of sediments, which will hinder the absorption of iron molecules by intestinal mucosa. Moreover, the stronger the green tea is, the greater the obstacle to iron absorption.

The first healthy drink is green tea, and the second is soybean milk. Hehe, these are all anti-cancer. If you want to say that you need to pay attention, don't drink too much. Too much is not good. Also, black tea causes cancer.

Here is some information about the benefits of green tea, you can have a look.

First of all, we must understand the ingredients of green tea. It has been proved by modern scientific research that green tea contains more than 450 kinds of organic compounds and 15 kinds of inorganic minerals, most of which have the effects of health care and disease prevention.

1, reducing fat and weight, preventing cardiovascular and cerebrovascular diseases. Drinking tea is closely related to losing weight. As early as more than 2,000 years ago, Shennong Materia Medica mentioned the slimming effect of tea: "Long-term service, peace of mind, benefiting qi ..... intellectual man fit and not old". Modern scientific research and clinical experiments have proved that drinking tea can reduce blood lipid and cholesterol and make the body lighter. This is because the comprehensive coordination of phenolic derivatives, aromatic substances, amino acids and vitamins in tea, especially the comprehensive function of tea polyphenols, theanine and vitamin C, can promote fat oxidation, help digestion and reduce fat and weight. In addition, tea polyphenols can dissolve fat, while vitamin C can promote cholesterol excretion. Green tea itself contains tea gan ning, which can improve the toughness of blood vessels and make them not easy to rupture. A study published in the Journal of Circulation of the American Heart Association in May 2002 shows that drinking tea regularly can reduce the risk of dying of heart disease. Researchers from Harvard Medical School in the United States conducted a follow-up survey on 1900 patients with heart disease, mainly the elderly over 60 years old. The survey found that those who drink more than 65,438+04 cups of tea per week have a lower risk of death within about three and a half years after a heart attack than those who don't drink tea. The study also shows that even if patients drink less than 14 cups of tea per week, it may reduce the death rate of heart disease by 28%.

2. Anti-cancer. Green tea contains tea polyphenols and caffeine, which have comprehensive effects, not only refreshing, but also improving human immunity and anti-cancer. In recent years, the American Chemical Society has always found that tea has an inhibitory effect not only on digestive system cancer, but also on skin, lung and liver cancer. It has been confirmed by scientific research that the organic anticancer substances in tea mainly include tea polyphenols, theophylline, vitamin C and vitamin E; The inorganic anticancer elements in tea mainly include selenium, molybdenum, manganese and germanium. Scientists in China and Japan believe that catechins in tea polyphenols have the best anticancer effect.

3. Anti-poison sterilization. The use of tea as a good antidote can be traced back to the ancient Shennong era (about 2737 BC). The saying that "Shennong tasted a hundred herbs and encountered 72 poisons every day, and solved them with tea" is recorded in Records of the Historian Huang San, Huai Nan Zi Xiu Wu Xun, Herbal Yi Yan and other books. Cha Sheng Lu Yu pointed out in the Book of Tea, the world's first authoritative work on tea science, more than 1200 years ago (AD 780), "Tea is the most suitable drink because it is cold ... If you feel hot, thirsty, stuffy, headache, tired eyes, tired limbs and uncomfortable joints, drink it four times. The above symptoms listed by Lu Yu are very close to typical pneumonia or suspected cases. Chen Zangqi, a medical scientist in the Tang Dynasty, wrote in Materia Medica: "Quench thirst and eliminate epidemic diseases. Expensive tea also. Liu Ye, a famous eunuch, listed "eliminating furuncle with tea" as one of the ten virtues of tea. Since the Tang Dynasty, there has been a new narrative in the study of tea by doctors in past dynasties, which is similar to detoxification and sterilization with tea. However, due to the underdeveloped science at that time, infectious and epidemic diseases were collectively called "plague" or "furuncle". Although bacteria and viruses are not specified, it has been proved that drinking tea is helpful for detoxification and sterilization. The research on the health care function of tea has been deepened in modern medical circles. In 2003, American scientists reported in the Journal of the American Academy of Sciences that "the chemical substance named' theanine' in tea can enhance the anti-infection ability of human body by five times".

4. Long life. The anti-aging effect of green tea on human body is mainly reflected in the coordination of several effective chemical components and various vitamins, especially tea polyphenols, caffeine, vitamin C, aromatic substances, lipopolysaccharide and so on. , can enhance human myocardial activity and vascular elasticity, inhibit arteriosclerosis, reduce the incidence of hypertension and coronary heart disease, enhance immunity, thus anti-aging and longevity. Medical research shows that tea polyphenols can not only reduce the contents of cholesterol and triglycerides in blood, but also enhance the toughness and elasticity of microvessels and reduce blood lipids, which is extremely useful for preventing and treating common diseases of middle-aged and elderly people such as hypertension and cardiovascular diseases. Tea contains selenium, and it is organic selenium, which is more easily absorbed by people than selenium in grain and oil. Dr Richard Paixiwat of the United States believes that adding selenium to food, combined with vitamin C and vitamin E, can prolong people's life, and tea is rich in these strange elements that are beneficial to life.

Birth, old age, illness and death are irresistible laws. The so-called "longevity" is false, and "longevity" is true. There are countless examples of longevity by drinking tea. According to Song? According to Qian Yi's Annals of New South Wales, in the third year of Emperor Xuanzong of the Tang Dynasty (AD 849), there was an old monk/kloc-0 in his thirties in Du Dong (now Luoyang, Henan). The emperor asked him how to keep in good health. He said, "I have few ministers and many ministers, and I don't know medical skills, so I am good at tea. As long as tea is everywhere, or I encounter more than 100 bowls of tea every day, as usual. " Qianlong was the longest-lived feudal emperor in China, who reigned for 60 years and lived to be 89 years old. Drinking tea is one of his health recipes. Su Juxian, the oldest birthday girl in Shanghai and the last scholar in the late Qing Dynasty, insisted on drinking tea as a big habit all his life. He lived to the age of 108 (according to the radical of the Chinese character "tea", it can be divided into "rice" and "eighty-eight", which is 108). 1994 Yuan Dunzi and Wang, a couple aged 104 who won the title of "Longevity Couple" in Shanghai, also drink tea every day, usually at 10 and 3 pm every morning. Born in 1896, Zhang Shun, a centenarian in Gaozhou, Guangdong Province, has four noes: no smoking, no drinking, no overeating and no picky eaters; Sixi likes coarse grains, sweet potatoes, jealousy and tea. 1898 Born in Fengshun County, Guangdong Province on August 20th, Zhang is a hardworking and long-lived woman who never smokes, drinks or drinks tea. Professor Wu Juenong, honorary chairman of China Tea Society, known as "contemporary Cha Sheng", celebrated his 90th birthday. When talking about the mystery of longevity of himself and his wife, he gave the answer of drinking more tea and eating more fruit. (Press: Wu Lao lived to be 9 1 year old, and his wife Chen lived to be 98 years old. ) The famous mathematician, consultant of Shanghai Tea Society and Professor Su of Fudan University lived to be 65,438+0,065,438+0 years old. Drinking tea after breakfast every morning is a way for him to live a long and healthy life. Mr. Cui Guiyong, President of Luyu Tea Classics Research Association of Korea, loved tea on weekdays and lived to 100 years old (died on April 5, 2002). In the northwestern Indian city of Gapur, there was an old man named Habibou Mian, whose age was officially recognized by the local government as 125. When telling the secret of his longevity, the old man Mian talked about his eating habits. "I never smoke. Drinking tea is my only addiction." There is a farmer's birthday girl named Zanadi michal in Egypt. He drinks more than 6 cups of tea every day, but he is lucky to live to be 130! Deng Xiaoping, a politician with ups and downs, loves to drink green tea. Deng Xiaoping's sister Deng Xianqun once recalled Deng Xiaoping's life during the Cultural Revolution and said, "My eldest brother likes drinking tea. He likes to drink green tea produced in Sichuan and Anhui, and sometimes drinks West Lake Longjing tea. Tea is still relatively expensive. He put a lot of tea in the cup, which will take up two-thirds of the cup when it is completely soaked. My eldest sister-in-law makes a cup of strong tea for my eldest brother every morning. When my eldest brother finishes drinking, my eldest sister-in-law will continue to drink the remaining tea roots and make him another cup in the afternoon. " The ancients called tea a medicine for all diseases. Tea can preserve health and prolong life, but it is important to persist and persevere, and you will see the effect. Drinking tea has a hundred benefits but no harm.

Although drinking green tea is good, there are still many regrets: 1, green tea is easy to oxidize and difficult to preserve. Tea polyphenols in green tea are strong antioxidants, so it is easy to nourish itself. Although the reason why tea polyphenols can make people live longer is still inconclusive, the tea brewed from oxidized old tea is coffee red, without tea fragrance, and the taste is greatly deteriorated. 2. Most people drink tea weakly and are not used to strong tea. Therefore, for the sake of health, the amount of tea they drink is insufficient. 3. Beware of "urea tea". What is "urea tea"? A few years ago, there was demand for tea, and tea farmers in some places had "technological innovation". After picking tea every morning, spray urea solution on the tea tree in the afternoon, and the tea will grow very long the next morning. This cycle leads to a sharp increase in tea production. Therefore, when drinking tea, we must recognize the brand and the quality, and we must not be greedy and cheap.

Evidence:

According to a new report from the Department of Hematology, Mayo Clinic, Rochester, Minnesota, USA, EGCG, a polyphenol antioxidant in green tea, helps to kill cells of B-cell chronic lymphoblastic leukemia (B-CLL). B-cell chronic lymphocytic leukemia; B-CLL is the second most common hematological tumor in American adults.

Researchers have found that EGCG can kill blood cancer cells by blocking their communication signals. This research report was published in the online magazine Blood on March 2, 2004.

Chronic lymphoblastic leukemia is most often diagnosed at the age of 65 ~ 69, and chemotherapy is usually used, but the effect is limited. Usually, chronic lymphocytic leukemia is incurable.

In a new study, Mayo Clinic scientists found that chronic lymphoblastic leukemia cells can synthesize and release vascular endothelial growth factor (VEGF; Vascular endothelial growth factor. B cells of chronic lymphocytic leukemia use vascular endothelial growth factor as a survival factor.

Eight out of ten patients with chronic lymphoblastic leukemia showed that EGCG significantly increased the death of leukemia B cells. In addition, EGCG also inhibits protein in B cells of chronic lymphoblastic leukemia. Finally, EGCG also inhibited the phosphorylation of VEGF-R 1 and VEGF-R2. These results show that the signal from vascular endothelial growth factor can regulate the survival signal in chronic lymphocytic leukemia cells, and blocking this autocrine pathway will lead to the activation of caspase, which will lead to the death of leukemia cells. Eight of the ten patients showed that EGCG caused the death of blood cancer cells.

Dr Neil E. Kay, the chief research scientist, said in a statement: "We will continue to explore therapeutic drugs that are non-toxic to patients but can kill cancer cells. This discovery about EGCG is a good starting point. The understanding of this mechanism and these preliminary positive results have given us great motivation to continue our efforts, hoping to provide more effective and harmless treatment drugs for cancer patients as soon as possible. 」

Source: Journal of Blood

Green tea is good for health and has new proof!

According to the latest research by the Institute of Food Science and Technology of National Taiwan University, green tea can improve hyperlipidemia and delay the occurrence of diabetes. People are advised to drink green tea every day. Professor Sun Luxi pointed out in the latest published research that green tea contains polyphenols such as catechins and colorless anthocyanins, which have physiological effects such as deodorization, antioxidation, anti-tumor, lowering blood pressure, lowering blood fat and cholesterol. Taking hamster as an animal experiment, it is found that green tea on the market can reduce serum triglyceride and liver cholesterol, delay the oxidation of low density lipoprotein cholesterol (bad cholesterol), restore the insulin sensitivity of mice, and help to prevent and treat type 2 diabetes.

That is to say, in order to convert the consumption of green tea in the experiment and clearly see the health care function of green tea in a short time, you must drink10,800 cc of strong tea every day, and the concentration is about 250 cc for a bag of tea. Generally, the concentration of green tea drinks on the market is only half. If sugar is added, the effect will be discounted.

People say that "drinking tea can remove oil and reduce fat", and now this statement has been confirmed by the research of Chengda Hospital. The basic principle is that drinking at least 450cc of tea every day can reduce body fat. In addition, Professor Lin Renhui from the Institute of Biochemistry, National Taiwan University School of Medicine also pointed out that the health care function of tea and tea polyphenols is that they can inhibit the synthesis of fat, thus inhibiting the formation of obesity and tumors, showing that tea and tea polyphenols have slimming and anti-cancer effects.

Drinking tea helps to lose weight, but some people think that it is wrong to drink tea to get greasy after eating. Under a normal diet, you can lose weight by drinking a cup after a meal and walking for half an hour. Nutritionists also reminded that it is best to choose green tea, unsweetened oolong tea and Pu 'er tea to reduce fat. The catechin content of black tea is relatively low, and milk tea absorbs unnecessary heat because of adding cream balls, which should be avoided.

Every kind of tea contains tea polyphenols. Tea polyphenols in green tea are called catechins, tea polyphenols in black tea are called theaflavins, and tea polyphenols in Pu 'er tea are called thearubigins. Tea polyphenols in Oolong tea are still under study because of their complex structure. Green tea is unfermented and contains the most catechins. Some fermented teas, such as steamed buns and oolong tea, have the second highest catechin content. Fully fermented tea, such as black tea, has the least catechin content, among which green tea has more tea polyphenols, and the health care effect has been studied the most.

If you don't like tea, or you can't drink a lot of tea, there are actually simpler and more convenient options. For example, there are many green tea extract products or capsule products on the market, but among many brands of green tea products, it is recommended that you choose the brand carefully. Besides paying attention to the hygiene and quality of products, it is more important to pay attention to the content of catechins. For your health, reminding you to drink more green tea or supplement green tea products will make you say goodbye to cholesterol, diabetes and obesity! Goodbye!