There is archaeological evidence that suggests that tea has been consumed for almost 5000 years, with India and China being two of the first countries to cultivate it. Green tea has been used as traditional medicine in areas such as India, China, Japan and Thailand to help everything from controlling bleeding and helping heal wounds to regulating body temperature, blood sugar and promoting digestion.

The Kissa Yojoki, or Book of Tea, written by Zen priest Eisai in 1191, describes how drinking green tea can have a positive effect on the five vital organs, especially the heart. The book discusses tea's medicinal qualities, which include easing the effects of alcohol, acting as a stimulant, curing blotchiness, quenching thirst, eliminating indigestion, curing beriberi disease, preventing fatigue, and improving urinary and brain function. Part One also explains the shapes of tea plants, tea flowers, and tea leaves, and covers how to grow tea plants and process tea leaves. In Part Two, the book discusses the specific dosage and method required for individual physical ailments.

Unproven claims

Green tea has been credited with providing a wide variety of health benefits, many of which have not been validated by scientific evidence. These claims and any for which academic citations are currently missing are listed here:

* Stopping certain neurodegenerative diseases such as Alzheimer's and Parkinson's

* Preventing/treating cancer

* Treating multiple sclerosis

* Preventing the degradation of cell membranes by neutralizing the spread of free radicals (which occurs during the process of oxidation).

* Reducing the negative effects of LDL cholesterol bad cholesterol by lowering levels of triglycerides and increasing the production of HDL cholesterol good cholesterol.

* Increasing fat oxidation (helps the body use fat as an energy source) and raising metabolism.

* Joy Bauer, a New York City nutritionist, says [the catechins in green tea] increase levels of the metabolism speeding brain chemical norepinephrine.

* Japanese researchers claim if you drink five cups of green tea a day, you'll burn 70 to 80 extra calories. Dr. Nicholas Perricone , an anti-aging specialist, appeared on the Oprah Winfrey show and told Oprah's viewers they can lose 10 lbs. in 6 weeks drinking green tea instead of coffee . However, the maximum calorie density of stored fat is 3500 calories in a pound thus 75 extra burned calories per day requires 40 weeks to lose 6 lbs. The weight lost might also been due to replacing a high caloric drink such as coffee with cream and sugar with a lower caloric drink such as green tea. The difference might be a few hundred calories per drink if the coffee contained other substances, such as sugar, milk, and dairy creamers.

* The major concern with drinking too much green tea is the caffeine it contains. Too much caffeine can cause nausea, insomnia or frequent urination.


Source : http://en.wikipedia.org