Tea caffeine: Metabolism, functions, and reduction strategies

Tea is a product made up from topmost part of the plant Camellia sinensis. This part includes bud, first leaf (next to bud), second leaf, and stem (spanning from bud to second leaf). Tea is the second most consumed beverage in the world, well ahead of coffee, beer, wine, and carbonated soft drinks. Clinical studies have demonstrated that one of the harmful effects of tea over consumption, at least in sensitive peoples is due to its caffeine content. In view of this, major points discussed in this article are the following: i) a brief overview on tea and its biochemical composition, ii) health effects of tea drink, iii) caffeine metabolism and its functions, iv) possible strategies for caffeine reduction in tea, and v) feasibility of tea improvement through biotechnological approaches.