The fermentation process of the leaves after harvest is what makes these teas different. Because green tea is the least processed and freshest of the teas, it has more health benefits than the others do. Green tea also contains significantly less caffeine than black tea, but it has been found that decaffeinated green tea lacks the health benefits that the leaves possess in their natural state. The benefits of the tea are also decreased when milk is added to the drink. Each kind of tea has a slightly different effect on the body.
Green tea is said to be good at night and supposedly has a calming effect.
The Chinese and Japanese believe that green tea purifies and cleanses the body. They also feel that it cools the body, where black and oolong teas heat the body. Green tea taken in moderation can reduce the risk of cancer, but if more than five cups a day are consumed, it may increase the risk of pancreatic cancer. Dr. Lester Mitscher, a professor of Medicinal Chemistry at the University of Kansas found in a study in September of 1997, that green tea has in it the strongest of any known form of anti-oxidants. Dr. Mitscher has devoted the past ten years researching green tea and it's health benefits.