In comparison to coffee, tea drinkers have lower rates of heart disease and cancer, although few clinical studies have been done. Doctors are carrying out research into the effect of green tea in men with prostate cancer. They hope it will be just one of the many studies that will be done on the benefits of tea. Generally tea drinkers are less likely to have heart disease or cancer, although the reason is still unknown.
One likely reason is the high levels of antioxidants in tea. Antioxidants, found also in fruits and vegetables, mop up the harmful free radicals produced by the body's chemistry.
Left unchecked, free radicals damage cell components like DNA and protein molecules, causing cancer. Black, green and oolong tea all come from the same bush - known as Camellia sinensis - which is known to carry a high level of flavonoids, one of the most potent types of antioxidants.