Green tea is made solely with the leaves of Camellia sinensis that have undergone minimal oxidation during processing.
Green tea has been consumed throughout the ages in India, China, Japan, and Thailand. Green tea originates from China and has become associated with many cultures in Asia from Japan and South Korea to the Middle East.
Recently, it has become more widespread in the West, where black tea is traditionally consumed. Many varieties of green tea have been created in countries where they are grown. Theories state that green tea has been used as a medicine in China for at least 4,000 years.
In traditional Chinese and Indian medicine, practitioners used green tea as a stimulant, diuretic (to promote the excretion of urine), astringent (to control bleeding and help heal wounds), and to improve heart health. Other traditional uses of green tea include treating flatulence (gas), regulating body temperature and blood sugar, promoting digestion, and improving mental processes.
The mean content of flavonoids in a cup of green tea is higher than that in the same volume of other food and drink items that are traditionally considered of health contributing nature, including fresh fruits, vegetable juices or wine. Flavonoids are a group of phytochemicals in most plant products that are responsible for such health effects as anti-oxidative and anticarcinogenic functions. Drinking green tea reduced the risk of esophageal cancer in Chinese men and women by nearly sixty percent.
There is evidence suggesting that regular green tea drinkers have lower chances of heart disease. There is also research indicating that drinking green tea lowers total cholesterol levels, as well as improving the ratio of good (HDL) cholesterol to bad (LDL) cholesterol.
New evidence is emerging that green tea can even help dieters. Although green tea does not raise the metabolic rate enough to produce immediate weight loss, a green tea extract containing polyphenols and caffeine has been shown to induce thermogenesis and stimulate fat oxidation, boosting the metabolic rate 4% without increasing the heart rate. Researchers found that men who were given a combination of caffeine and green tea extract burned more calories than those given only caffeine or a placebo.
Green tea can even help prevent tooth decay! Just as its bacteria-destroying abilities can help prevent food poisoning, it can also kill the bacteria that causes dental plaque.
Skin preparations containing green tea - from deodorants to creams - are starting to appear on the market.