Caffeine Green Tea

Caffeine green tea is very related and now,many people are trying to get away from their daily coffee fix, and are turning to tea, in particular green tea, as a healthy alternative. For over 4,000 years the Chinese have been consuming green tea, in part, because of its perceived health benefits. The list of diseases that are believed to be prevented or improved include cancer, rheumatoid arthritis, and cardiovascular disease. Drinking green tea is said to lower blood cholesterol levels and fight infections. But if you are switching to green tea to avoid the caffeine, it might not be as simple as you think. Coffee is one of the most popular drinks in the world, but is also notorious as a source of caffeine. Indeed, many people drink coffee just to get a jolt and to delay fatigue. Caffeine stimulates the central nervous system, the cardiac muscle, and the respiratory system. Because of this stimulatory effect, caffeine loading is now banned for many competitive athletes. Caffeine is also a diuretic (a drug that increases the rate of urine excretion). Signs of over consumption of caffeine include irritability, sleeplessness, irregular heartbeat, dizziness, vomiting, diarrhoea, headache, or loss of appetite. Women are cautioned to reduce their caffeine intake during pregnancy. Green tea, unless it is decaffeinated, also contains caffeine. Normal green tea itself may contain more caffeine than coffee, but the length of infusion with hot water, and the number of time you use the green tea leaves can greatly reduce your caffeine intake. Experiments have shown that tea after a first 5 minute brew contains 32 mg caffeine. But if the same leaves are then used for a second and then a third five minute brew, the caffeine drops to 12 mg and then 4 mg. In all cases, it should be remembered to never brew or drink green tea with boiling water. In some countries, water heating pots have temperature controls to heat water for green tea preparation. The high temperature can destroy valuable therapeutic compounds found in green tea, Table 1: Caffeine Content of Some Common Drinks (per 100 ml) Coffee brewed from grounds 40 mg1 Expresso coffee 212 mg1 Instant coffee 26 mg1 Coffee liqueur(63 proof) 26 mg1 Lipton black Tea (bag 33 mg2 Green tea (loose leaves) 32 mg2 Tips If drinking green tea still has undesirable effects, consider the alternatives. Flower and herbal infusions are not Camellia sinensis and do not contain caffeine. Rooibos and honeybush, both from South Africa, do not contain caffeine but do contain high levels of antioxidants, however, so you still get the health benefits minus the caffeine. If green tea is steeped in cooler water (158 degrees F), relatively more caffeine and antioxidant polyphenols will be extracted in the second infusion. When hotter water (about 185 degrees F and above) is used, more caffeine and polyphenols will be extracted during the first infusion. (See Source by Yang et al below.) Be aware that the green tea polyphenols, such as epigallocatechin gallate, are the primary antioxidants that are found in green tea. These antioxidants have been consistently shown to protect liver function due to their antioxidant and antiinflammatory properties. The polyphenols may also protect against certain types of cancer, heart disease, diabetes, and neurodegenerative disease. It is also assumed that the polyphenols help to protect against the deleterious effects of caffeine. It has been theorized that when caffeine is consumed in moderation, especially as a natural part of a polyphenol-rich beverage such as green tea, the caffeine actually provides health benefits. (See Sources by Zhen et al, Chen et al, Wang et al, and Paganini-Hill et al below.) Theanine is calming and has been shown to partially counteract the rise in blood pressure that can occur with caffeine intake

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