Tests at a Consumer Reports laboratory found teas brewed from loose teas or tea bags had the most antioxidant power. Next come instant teas, then bottled teas. Bottled teas usually contain lots of water and sugar, and not much tea. Steeping tea for 3 to 5 minutes releases the highest level of antioxidants. Tea is good for your teeth.
Black tea contains enough fluoride to help prevent tooth decay.
Green tea contains twice as much. Green, oolong and black teas contain about 40 milligrams of caffeine, or half the caffeine found in a cup of brewed coffee. Caffeine content will vary depending upon how much tea you use and how long you steep it. It is unknown whether decaffeinated teas have the same polyphenols and potential health benefits as regular teas. Herbal teas do not have the benefits of regular tea.