Tea contains tannin, catechin, Vitamin E, Vitamin C, Natural fluorine and Polysaccharides. tannin and catechin have been associated with preventing cancer and heart disease Coffee contains caffeine, trigonelline, chlorogenic acid, phenolic acid, amino acid, carbohydrates, minerals, organic acids aldehydes, ketones, esters, amines, and mercaptans. Some antioxidants in coffee have been associated with fighting disease or enhancing health.
Caffeine content and effects
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.