The tree's scientific name is the Camellia sinesis. Most of these trees grow in the tropical and temperate regions of Asia. About 800 A.D., green tea made its way from China to Japan. Now tea leaves are cultivated in Asia, Africa and South America. There are three main types of tea, depending on the fermentation.
Green tea is unfermented, oolong tea is semi-fermented and black tea is fermented.
Its leaves have about 200 milligrams per 100 grams of dried leaves. In addition, green tea contains natural fluorine, which is thought to aid in the reduction of cavities in school children. Green and black tea have also been shown to inhibit the development of lung cancer and have preventive effects on oral cancer, according to Broihier's study of research on the subject. Black and green tea also contain strong antioxidants called catechins and flavonols. Dr. Yamamoto claims antioxidants are important because they counteract the oxidative damages done by free radicals.