Green tea can prevent cancer, even in Europe and America people have started to attach importance to green tea, which we have drunk for several thousand years. But the benefits of the green tea will it be the same for black tea and Pu-erh tea? How much should drink, how to drink, what is the best for the health?
There was once an epidemiological survey done in Shizuoka, Japan. It discovers that compare from other regions, the locals in Shizuoka has relative low rate of people died from gastric cancer. The analysis finds that the residents in Shizuoka had the habit of drinking tea.
Green tea has not only set off an upsurge in Japan, and even in European and American countries, where cancer is the number one enemy. Over the past decade, many countries have extracted the effective ingredients, such as catechins. It was used to injected on big or small mouse, conducting researches on the effects of varied cancer prevention and inhibition, which have proved that it has certain level of prevention and suppression on gastric cancer, lung cancer, breast cancer, colon cancer, liver cancer, skin cancer and other cancers.
Every tea is the natural health foods
The most recent preliminary research done by Institute of Food Science and Technology, National Taiwan University, has proved that black tea, Pouchong tea and Oolong can also prevent cancer. “Also we believe the effect is not less than the green tea!” Professor Sun Luxi has expressed this optimistic view.
Japanese people is the one who first find that the reason that green tea can prevent cancer is because catechin (EGCG) has the effect of antioxidant. What makes Sun Luxi surprised and excited is that even though during the fermentation process of Pouchong, Oolong and Black tea, some of the catechin contained in green tea turned into theaflavin and thearubigins. “But as long as there is still polyphenol, the antioxidant effects are still there.”
Drinking tea every day is the most important
Although according epidemiological statistics, the chance of getting cancer for tea drinkers is not lower than non-tea drinker. But the most important thing is to have long-term drinking habit, which will have effect.
However, we must clarify that “we believe drinking tea can prevent normal cells turn into cancer cells before the emerging of the cancer cell. Not because drinking tea can cure cancer.” The Biochemistry Professor of National Taiwan University, the School of Medicine, emphasize that tea should not be treated as drugs.
He points out that the speed of the division and growth of cancer cell is faster than that of the normal cell. The animal experience also finds that the catechin will affect the growth speed of the cell directly, which prove that catechin can inhibit the growth of cancer cell.
There are many environmental carcinogen, therefore, we must prevent cancer. Tea needs to be drank every day. Lin Renhun says, according to the animal experience conducted in Japan, a human weighted 60 kg, must drink 10 cup of tea each day. The concentration of the catechin should be 60 μmol (a unit of molecular weight) in every 150 cc.
Among the long-living emperors, Wu Zetian from Tang Dynasty, Kang Xi and Qian Long from Tang Dynasty, are all tea lovers, who cannot live without drinking tea. Qian Long were still in good health in his old age. He is quick thinker with good hearing and sight at 80 years old. It is said that tea drinking might be his secret of long-living.
To prevent cancer, you must drink every type of tea. Also, tea drinking and tea eating need to take in turn. Because there are some nutrients in tea leaves that do not dissolve in the hot water, such as fat-soluble carotene, vitamin e, minerals, manganese and dietary fiber, which cannot be absorbed by drinking. So, tea can be used in cooking, which is also a good way to absorb the nutrients in tea.
Currently, there are many ways of eating tea on the market, such as adding green tea powder into the dishes, yogurt, ice-cream. However, the green tea power is different than the Japanese Matcha.
Ruan Yiming, head of the Taiwan Tea Improvement Factory, who has been to Japan to collect information on match, points out that the raw material and processing methods of green tea powder and matcha are different, the prices varied largely.
The tea leaves used in making matcha are selected based on quality. Every year, it only uses spring tea. During the growing period of the tea bud, it need to reduce the sunlight in the daytime, which will improve the contained amount of chlorophyll and the sweetness of tea. At the same time, it will lower the amount of catechin and reduce the bitterness. Comparatively speaking, green tea powder is not so delicate.
“In fact, every tea contains catechine, the only different are in quantity and quality. Therefore, the effects on the health are different.” Explained by Sun Luxi.
Prevention of cardiovascular disease
Drinking tea can lower the blood pressure, blood viscosity, therefore tea can prevent the thrombosis, which has been proved in several animal experiments.
Sun Luxi analyzed that according to many research conducted abroad, tea drinking is good for health, especially because the effect of polyphenols has on antioxidant, anti-cancer. It can slow atherosclerosis, reduce the chance of suffering from heart disease and stroke. Taking green tea as example, which has been most studied, 80% are catechin.
Ruan Yiming points out that catechin can reduce the “bad” cholesterol – low density lipoprotein (LDL), improve the “good” cholesterol – high density lipoprotein (HDL). Adding 0.5 – 1% catechin into the feed for rats, it will increase the total cholesterol inside the body, free cholesterol, low-density lipoprotein and triglyceride levels. Simultaneously, it increases the high density lipoprotein. Additionally, the cholesterol and lipids in the fecal excreted have increased.
In additional, the study shows, catechin prolonged blood coagulation, and increased the products of the resolved fibrinogen. It indicated that tea has the function of antithrombotic and prevention of cardiovascular disease.
Green tea has effect of lowering bllod lipid, which known by everyone. However, Sun Luxi were surprised to find in his animal experience, the popular Pu-erh tea also have the ingredients that can lower the cholesterol level, which can increase the cholesterol excreted from fecal and reduce the synthesis of cholesterol in liver. However, the name of such substance need to be evaluated further.
Many people may have the experience, when you finish eating and drinking alcohol, take a cup of hot tea, you will always feel refreshed and eliminate the dryness at the mouth caused by foods and alcohol.
Prevention of diabetes and hypertension
Professor Lin Renhun says, the “tea drinking” of Guangdong and Hon Kong, is drinking moderate Pu-erh tea. According to the experience of most people, once finish a greasy meal, drinking tea will make you feel refreshed. “Because drinking tea can lower the fat in body, blood and cell, especially for long-term drinking, the effect is more obvious.”
Diabetes and hypertension is a commonly seen disease of middle age people and elderly. And it can only be controlled by drugs, and cannot be cured. The clinical trials conducted in Japan find that, people who are struggling to find the solution, instead of looking for panacea, drinking tea every day can reduce the blood sugar and sodium.
Recently, Japanese scientists recently extracted a water-soluble polysaccharide compound hetero chain from the tea leaves, conducting clinical trials on a hundred diabetic patients. The results show that there is significant decreasing in the level of blood sugar and urine sugar.
And tea is rich in potassium, can promote the exclusion of sodium and high sodium content is the main reason contributed to high blood pressure. The potassium soluble in water easily. Therefore, tea has the effect in prevention high blood pressure.
In Japan, green tea is particularly favored by women who is interested in losing weight, because the green tea advocates for health and weight losing. This trend has even affected domestically, but why can drink green tea help lose weight?
Ruan Yimin says because catechin will combine with the protein and fat in the food, affecting the gastrointestinal absoption of essential amino acids and reduce the intake of calories. However, if you want to lose weight by drinking tea, you have to combined with exercise, which will have significant result. “According to the animal experience abroad, a tea before, during and after exercise, it will accelerate the consumption of fat.”
People who want to lose weight must wonder which tea is the most effective? Sun Luxi says: “Pu-erh has the most obvious effect.” It might because during the fermentation process of Pu-erh tea, the mold will create a compound that can reduce the hepatic synthesis of cholesterol. However, which chemical composition affects the synthesis of cholesterol, what changes happened during the process, have to be prove with further experiments.
Tea can kill bacteria in the mouth
In the “Dream of Red Chamber”, it mentioned Jia family has the habit of mouthwash with tea after meal. Su Dongpo writes in his poem that “I have a method, which I value it very much. Every time after eating, I will wash my mouth with tea, it will help with stomach digestion.”
Tea can prevent tooth decay, because the fluorine in the tea, especially the old tea leaves, which contains the highest level of fluorine. Additionally, the tea polyphenol compounds have a strong effect in killing bacteria. It can inhibit the synthesis of insoluble dextran, and therefore constitute a comprehensive effect in preventing tooth decay with fluorine.
In Japan, it has been discovered a long time ago that green tea can remove bad breath, and the results is better that the deodorant products in the market. Regarding whether black tea can remove bad breath, Professor Sun Luxi, who is highly interested in this subject, find recently in the fermentation process of tea, the theaflavin and thearubigins both have the effect of removing bad breath, antibacterial and antioxidant. The effect in removing bad breath is even better than green tea.
However, to be able to effectively inhibit the bacteria in the mouth, you must leave the tea in your mouth for 15 minutes. “Maybe you can drink black tea during the day to remove bad breath, using green tea to wash your mouth before you went to sleep, and left the tea flavor inside your mouth.” Suggested by Sun Luxi. Additionally, because catechin can only be dissolved in water, if you want to remove bad breath by eating tea leaves, the tea should be soaked before chewing.
Tea catechins can kill or inhibit harmful to human pathogens, such as staphylococcus aureus, vibrio cholera, Escherichia coli, salmonella enteritidis, salmonella typhi, botox and others. Also, tea can improve the intestinal bacteria and microbes, and promote the growth of beneficial bacteria. For many harmful intestinal bacteria, it can inhibit the growth of them.
What need to be paid attention to:
- Don’t drink overnight tea
Drink freshly brewed tea, not only will give you the strong flavor, the nutrients are more abundant. It also reduces the chance of the bacterial breeding. Drinking overnight tea, especially during the infectious disease-prone season, will create convenience for the spread of pathogens.
Tea after oxidation, contacted with air, may grow mildew or climb by insects. Drinking this tea will lead to diarrhea. “As long as the tea is not rancidity, mildew, it will not harm the body.” Explained Ruan Yiming.
- Don’t drink tea with empty stomach
In tea, especially the green tea, because the catechin contained in tea is not very stable, very active, “it is easily combined with protein, stimulate the stomach, which will hurt the stomach. Therefore, you should better not drink tea with empty stomach.” Sun Luxi reminded. People with gastric ulcer or stomach pain should avoid drinking tea.
Ruan Yimin says, because of the strong convergence of catechin, it will not only bring astringency, and will also combined with mucous membrane glycoprotein in the mouth, causing damage to mucous membrane. The stronger the damage, the more astringency it tastes. Esophagus, gastrointestinal are also covered by mucosa, so catechin can also hurt the stomach.
To reduce the astringency of tea, Cai Youren, head of the Wenshan District Tea Improvement factory, says the shorter the brewing time, the faster the pouring speed, and separating the tea with the tea leaves, in this way it will reduce the astringency of tea.
- Tea should not be brewed for too long
Whether teapot, tea cup, tea boiler, and tea leaves, should be avoid contaminating by the other smells such as coal, smoke, oil and others. Any types of tea should not be brewed too long. Tea and tea leaves should be separated. You should drink the tea once brew it. Tea should not be too strong, otherwise it is bad for health. Also, it will destroy the unique flavor and taste of tea. Normally, Ruan Yimin only uses 15 – 20 grams of tea, and drinks tea like water.
If tea is brewed for too long, it will dissolve too many caffeine, which will affect the taste of tea.
- Tea contains caffeine
Because tea contains caffeine, so it can refresh your brain. However, many people worries they might not be able to fall asleep if they drink tea at night. Some people even think black tea contains higher level of caffeine.
Sun Luxi clarifies that the caffeine changes not much during the fermentation process. According to the research, there is no evidence shows that black tea contains higher level of caffeine. However, because most of the black tea bags contains tea leaves in powder, which is easier to dissolve the water soluble ingredients, including caffeine. Thus, the amount absorbed will be increased.
Because each person has different level of tolerance. If strong tea will not affect sleep, it will not be a problem. However, if you have problem sleep, it is better not to drink any tea after 4 or 5 o’clock in the afternoon. The recommended amount based on international standards is mainly 2%: every 2 grams of tea leaves per 100 grams of water.