Buddhist monks originally brought Green Tea to Japan from China. It was quickly embraced by the Japanese as a soothing, calming drink, and was rapidly found to have numerous health benefits. Today Green Tea is recognized all over the world for its therapeutic properties.
Green tea comes from the same plant as traditional black tea, Camellia Sinesis and is produced by steaming and drying fresh tea leaves at elevated temperatures in order to keep the active ingredients intact.
Green tea has several important therapeutic functions ranging from increased energy to cancer prevention and treatment. It is probably best known in North America for its ability to increase weight loss. Although the exact mechanism is not clear, a few modes of action have been postulated.
Firstly, the catechins in green tea inhibit the enzyme catecho-O-methyltransferase (COMT), which is responsible for breaking down norepinepherine. By increasing the life span of this neurotransmitter its activity is increased. Interestingly this increase in activity appears to specifically boost metabolism and calorie burning (a process known as thermogenesis) without any cardiovascular stimulation such as increase in heart rate or blood pressure.
Secondly, the extracts from green tea inhibit phosphodiesterases, thereby increasing the life span of cyclic AMP (cAMP) in each cell. This aids in the utilization of fatty acids and their conversion into energy, as well as heightening the impact that norepinephrine has on thermogenesis and fat oxidation for weight loss.
Green tea contains powerful antioxidants, called catechins and has six times more antioxidant activity than black tea. Antioxidants help to decrease the cellular and DNA damage caused by environmental toxins that can result in the stimulation and progression of cancer and other age-related illness such as cardiovascular disease and macular degeneration. It is imperative that the tea be consumed without milk in order for the antioxidants in green tea to be active. The proteins in milk bind to the tannins in the tea rendering them useless.
Green tea has also been shown to be a very useful nutrient for athletes. Studies show that taking green tea extract (0.5% extracts) can boost endurance and exercise performance by up to 24%. The research reveals that part of this effect was due to increased muscle lipid oxidation, which allows the body to utilize energy stores more readily.
Green tea also possesses anti-cancer properties. Numerous epidemiologic and animal studies have indicated that green tea extract is effective against several human cancers, including bladder and colon cancer. In laboratory studies it has been shown to induce death in cancer cells, as well as inhibiting the development of the independent blood supply that most cancers rely on to grow. Its mechanism of action appears to be through an effect on actin remodeling, an event associated with cell movement, reproduction and growth. For cancer to grow and spread, the malignant cells must be able to move and it is this movement that depends on actin remodeling, a process carefully regulated by complex signaling pathways. Green tea catechins have been shown to induce maturity and cell adhesion in cancer cells, inhibiting their movement and thus potential spread of cancer. In addition, localization of cancer cells makes them easier to treat.
Looking at all these benefits, it is no wonder that this simple tea extract has spread in popularity throughout the world. For those not partial to a hot brew, the active ingredients are available in supplement form.