Coffee has just one real claim to fame—its caffeine content. Granted, caffeine is useful in alleviating asthma by helping relax the airways in the lungs. But that's about the extent of its practicality for health purposes.
By contrast, tea is known for its abilities to fight both cancer and heart disease. There are two types of teas, black and green, which are essentially the same plant, Camellia sinensis. The difference is that black tea leaves are fermented; green are not. Teas of both varieties contain polyphenols, a class of flavonoids. These compounds function as powerful antioxidants that can protect your body from free radical stress. The most notable of these is quercetin, well known for its ability to temper allergic reactions and interrupt the oxidation of LDL, or "bad," cholesterol. Quercetin can also be very useful in helping to fight and prevent cancer. Apples and onions are some of the other foods that contain quercetin in high amounts. Green tea may prevent cancer, restrict blood cholesterol, control high blood pressure, lower blood sugar, suppress aging, deter food poisoning prevent and treat skin disease, stop cavities and fight viruses.
Coffee, no strong results suggest that coffee may enhance health as greatly as Tea does. But it does help in combating drowsiness, temporarily boosting athletic performance, easing congestion due to colds and flu, preventing asthma attacks and enhancing the pain-relieving effects of aspirin. So, one can safely conclude that Tea, especially Green Tea offers great health advantages in long term over Coffee.
Tea: Tea has approximately 55 milligrams of caffeine per cup. Various teas contain different amounts of caffeine. Green tea contains the least, about one-third the caffeine as black and oolong about two-thirds as much. The caffeine in tea is said to increase concentration, and enhance the sense of taste and smell. The effect of caffeine in tea usually takes longer to enter the blood stream than coffee therefore, seems gentler to the system. About 80% of the caffeine in black tea can be removed easily at home
Coffee: Coffee has approximately 125-185 milligrams of caffeine per cup. The caffeine in coffee is sometimes associated with a lift followed by a letdown. The effects of the caffeine in coffee are immediate and sometimes arouse feelings of anxiety known as "coffee jitters". Many varieties of decaffeinated coffees are available on the market today. Note: Studies have shown that tea or coffee drunk in moderation (two [it reported] cups of coffee a day and four or five cups of black tea) has no harmful effects.