Not All Teas the Same
~ June 2002 No.150 ~
After water, tea is the most popular beverage next to water that is consumed around the world. In some cultures it has a long tradition and has attained a status that is rooted in history. Tea is known for its soothing pleasant taste, and “tea time” is a custom that provides a tranquil break in many peoples' hectic days. Tea is also a good source of antioxidants.
Antioxidants are complex chemical compounds that help the body fight harmful free radicals. Free radicals are unstable molecules which occur naturally in the body and are an essential part of the body's metabolism. However, excess amounts of free radicals (caused by excessive sunlight exposure, smoking, pollution, excessive exercise etc) have been associated with an increased risk of coronary heart disease and cancer.
The antioxidants in tea are similar to those in fruits and vegetables. High levels of antioxidants in the diet have been linked to lower rates of cancer and heart disease. Tea also has been found to interfere when cancer-causing substances bind to DNA
Tea is also a very complex beverage; it is the antioxidant content of tea that has caught the attention of health scientists. However, like so many other things, all teas are not equal. All teas do not contain the same amounts of certain beneficial antioxidants.
This was the message that Dr. Susan Henning recently gave to a meeting of the American Society of Clinical Nutrition
Dr. Henning presented data on the amount of catechin - a well characterized antioxidant - found in different teas. Depending on the brand and type of tea, the catechin content ranged from below detectable limits to over 200 mg of catechin. She reported that ice tea mixes and one peach ice tea drink contained the lowest levels of catechin (below levels of detection), while two brands of green tea when brewed for 2 minutes had the highest levels of catechin. At the present time there is no labelling legislation that would require tea companies to report the levels of catechins in their product.
Once tea is made, either by brewing leaves or by mixing granules, it should be consumed or refrigerated. Left uncovered, it can lose its antioxidant concentration; it also can become a good place for unwanted bacteria to grow.
Most of the recent research has involved green tea, but black tea also impresses health researchers. Both green and black tea come from the same plant, but after picking, the tea leaves are treated differently. Green tea is more popular than black tea in certain parts of the world - especially Asian countries. However, many green tea based products including green tea ice cream are now appearing in the West, in part due to the reputed health benefits of green tea.
To get the best out of tea, proper brewing procedures should be followed, and as the study of Dr. Henning shows, the health promoting properties of tea is not the same for all products on the grocery shelf. Become more informed -it's your health.
Catechin Content of Various Teas and a Green Tea Extract Supplement Correlate with Antioxidant Activity: Implications for Studies of Nutrition and Cancer Prevention.
Am J Clin Nutr 2002,75:339S-439S P192