Introduction to Green tea
Green tea is one of the most popular beverages in the world. Green tea is most popular in United States, United Kingdom, and Europe. Green tea is most popular among Japanese and Chinese people.
Tea is made from the immature leaf parts of the Camellia sinensis. Immediately after harvesting tea leaves starts to wilt and oxidize. Leaves have more chemicals that are broken down by enzymes during the oxidation process. It results in the darkening of leaves and recognizes the aroma of tea. Therefore, heating can stop this process. Heat has inactivated the enzymes.
Ingredients of Green Tea
Green Tea contains Polyphenols, Alkaloids (Caffeine, Theophylline, and Theobromine), Amino Acids, Carbohydrates, Proteins, Chlorophyll, Volatile organic compounds, Fluorides, Aluminum, Minerals, and elements. Polyphenols are a large group of plant chemicals. It includes Catechins. Catechines are responsible for most of the health benefits, especially in green tea. Black tea contains a somewhat lower concentration of Catechins than green tea. There are two types of complex polyphenols in black tea namely, Thearubigins and Theaflavin. In the extended oxidation process, these two chemical concentrations are an increase in the black tea.
There are two other value-added products (Iced tea and Ready to drink tea) that are becoming very popular worldwide.
They have not contained an equal volume of Polyphenols as a brewed tea. The concentration of Polyphenols is depend on the type of the tea, the amount used, the brewing time, and the Temperature. So brewed hot tea contains the highest concentration of Polyphenols.
How to Prevent Cancer by Drinking Tea
Predominant Polyphenols. in green tea and Theaflavins and thearubigins in black tea have antioxidant activity. This function may protect cells from DNA damage caused by reactive oxygen species. Polyphenols are inhibited tumor cell proliferation. And many studies have shown that Catechins are inhibited angiogenesis and tumor cell invasiveness. Polyphenols protect against damage caused by UltraViolet radiation. Green tea contains special detoxification enzymes such as Glutathione S-transferase and Quinone reductase. They help to protect against tumor development.
More than 600,000 new skin cancer patients are diagnosed each year. Most of these patients suffer from basal cell cancers and squamous cell cancers. This type of cancer can be cured. Exposure to Ultra Violet Radiation coming from the sun is the main risk factor for skin cancer. This type of cancer is common among fair-skinned people. Because this type of skin burns easily. There are four stages of skin changes when suffering from skin cancer.
- Irregular growth
- Borders irregular
- Color variation within the growth
- Diameter exceeding 6 mm
So, in laboratory experiments, cells are growing in the petry dishes in standard conditions and indicate green tea extract orally or apply directly to the laboratory animals. One of the studies proved, green tea has the ability to prevent skin cancer in the mouse skin cancer model. Another study has found that green tea cream applied to the skin before exposure to UV radiation prevents skin damages. So green tea extract is more protective before cancer develops in the skin. Some of the researches have shown that green tea extract inhibits the development of melanoma. It is a serious and deadly form of skin cancer.
Recent Epidemiological studies of the human population show that people who drink tea at normal hot temperatures (950F – 1150F) do not have a higher risk of cancers. There is a preventive effect of tea Polyphenols on Esophageal cancer. In one of the studies, a group of rats was exposed to cancer-promoting chemicals that would normally result in 95% of esophageal tumors. Some of the rats were also given green tea and black tea extract. The result was tea-treated animals that did develop cancer were smaller in size and had fewer tumors. And they showed poor esophageal health, abnormal skin growth.
Gastrointestinal Track Cancer
One of the Japanese regions of Shizuoka is noted that people who drink more than an average amount of green tea have a low risk of stomach cancer. Most of them are drinking ten or more cups of tea daily. They had a much lower risk of developing cancer. These studies suggest that tea may disrupt the intermediate and late stages in the development of stomach cancer. Green tea has an effect on cancers that may develop in the Cardio and distal areas of the stomach.
Cancers of the large intestine are less common when people are fed Polyphenols from green tea.
The digestive track is ended from the Colon and Rectum. Colon and Rectum cancers are the second most common cause of cancer deaths in the United States and more than 133,000 new cases have been diagnosed every year. The mortality rate from colon cancer is high. This type of cancer can be caused by environmental factors. The most common preventive method is Chemotherapy for controlling this disease. Colon cancers are much lower in Asian countries than the United States and Europe. Because Asians drink more plenty of teacups every day.
Chemopreventive agent against colon and rectum cancer available in tea. More specially, tea inhibits colon cancer progression as indicated by a lower incidence of crypt cells in the colon. Tea extract may protect the mucus lining of the colon from free radical damage. The very low dosage of tea extract prevents the formation of colon tumors.
Lung cancers are a more dangerous type of cancer. Because its mortality rate is very high. Both men and women suffering from this cancer type. Lung cancer can be traced by exposure to cinogens from cigarette smoking, asbestos, radiation, and radon. Tea extract has a chemopreventive agent against lung cancer. A study suggested that drinking black tea increased, rather than minimized the risk of lung cancer.
But doctors advised that the incidence of lung cancer would avoid if people would stop smoking. Because smoking is caused to 90% of all lung cancer cases.
Regular green tea consumption people have blood profiles similar to that of a non-smoker, while the men who did not drink tea showed unhealthy levels of Tobacco-derived carcinogens in their blood. But not smoking is the first choice for health.
Pancreatic cancer is a major killer. Immediately after diagnosing the disease, patients may die. Therefore this one is more dangerous. There are no effective treatments for this cancer type, but prevention is more important. One of the studies has proved a strongly significant trend of decreasing risk with increasing lifetime tea consumption.
Environmental factors mainly affect bladder cancer. This cancer is most prominent among cigarette smokers and industrial workers. International Cancer Research Agency is shown that smokers with a high intake of Polyphenols are partially protected from harmful effects and drinking green tea may lower the risk of bladder cancer in women.