Most tea consumed worldwide comes from China and from a single plant: Camellia sinensis. Green tea, less oxidized than black and oolong teas, contains a high number of antioxidants. It is known to increase alertness and may reduce cholesterol and promote cardiovascular health. Evidence also suggests green tea helps you lose weight, although perhaps not as dramatically as some advertisers suggest.
Green Tea Weight Loss Study
Green tea helped men lose about ½ lb. per week in a 12-week trial conducted in the United States by Kevin Maki and other researchers. The men in the study who drank about 6 cups of green tea lost an average of 5.4 lbs. This compares with the men in the study who drank black tea and lost an average of 2.9 lbs. All the men in the study followed a restricted diet and exercised, so not all of the weight loss can be attributed to drinking tea.
Green Tea Antioxidants
The antioxidants in green tea are called epigallocatechin gallate, more commonly referred to as catechins and sometimes abbreviated as EGCG. If you're reading labels on a box of green tea bags, you might also see them listed as flavonoids or polyphenols. Catechins exist in all types of Chinese tea as well as in some foods such as blueberries, dark chocolate and blackberries. Green tea gets a lot of attention because it contains so many catechins. In Maki's study, for instance, the green tea drinkers consumed 660 mg of catechins daily while the black tea drinkers consumed just 22 mg.
More Catechins in Tea Brewed From Loose Leaves
If you want to use green tea as a weight loss tool, you'll have greater success if you brew tea from loose leaves. They contain about 127 mg of catechins per cup, according to the United States Department of Agriculture. Organic tea bags contain the next highest amount --- about 100 mg per cup. If you buy commercial tea bags, check the labels carefully. Some contain nearly as many catechins as organic tea and some contain few more than bottled green tea, which has about 12 mg of catechins. You could drink 5 or 6 cups of tea brewed from loose leaves or 55 cups of bottled green tea to obtain 660 mg of catechins, the amount consumed by the most successful participants in Maki's study.
How to Brew
If you want your green tea to contain the highest possible number of fat-burning catechins, don't use boiling water to brew it. Keep the temperature between about 140 and 185 degrees. If you don't have a food or candy thermometer, an easy way to achieve the proper water temperature is to boil the water, then pour it into a glass container and let it sit for several minutes before pouring over tea leaves. It only takes a couple of minutes for green tea to steep properly, but you can adjust the time according to your own tastes. You can reuse green tea bags five or six times, but the amount of catechins will decrease slightly with each brewing.
Caffeine in Green Tea
Green tea contains caffeine. The amount is considerably lower than in coffee or black tea and depends on the type of tea brewed, how long you steep it and how many times you reuse the leaves or tea bags. If you are sensitive to the effects of caffeine, you should consult your doctor become consuming. Pregnant women should limit their caffeine intake to no more than 100 mg daily, according to the "British Medical Journal." Green tea may also interfere with some medication, including a cancer drug called bortezomib.
References
- "The Globe and Mail"; Green Tea Blocks Cancer Drug Benefits; Carly Weeks; Feb. 4 2009
- "Journal of Nutrition"; Green Tea Catechin Consumption Enhances Exercise-Induced Abdominal Fat Loss in Overweight and Obese Adults; Kevin Maki etal; February 2009
- USDA: Brewing Up the Latest Tea Research
- "The Washington Post"; Give Green Tea a Try, but Get a Handle on the Perfect Brew for You; Robert L. Wolke; April 25 2007
- The Fragrant Tea Leaf: Green Tea Brewing Tips
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