Philip J. Goscienski, M.D.
April 2006
Tea drinkers don't get the jitters. I've never heard anyone complain about tea nerves but many if not most Americans have had a case of coffee nerves. Is it time to switch to a more tranquil and possibly more healthful beverage? Starbuck's tea houses may be far in the future but interest in this Asian drink is picking up.
By the time the Chinese discovered tea our Stone Age ancestors had probably been brewing beverages made from plants for a few thousand years. Such herbal infusions (they are not really teas) have drawn little attention from scientists; the variety is enormous and so is the cost of such exploration. True teas come from a single species of plant with only a modest number of varieties. The degree of drying and fermentation determines whether a tea is white (none), green (dried but not fermented), oolong (slightly fermented) or black (fermented for several hours).
In the laboratory, tea can slow down cancer, reverse diabetes and turn back heart disease. Studies among humans, though encouraging, are less conclusive. Several studies, not just in Asia, indicate that persons who drink tea almost daily have less cancer, especially that which involves the intestinal tract and the urinary system. Researchers give credit to flavonoids, the multitude of chemicals that you also get from fruits, vegetables, red wine and dark chocolate.
In one study, drinking black tea increased blood flow through the coronary arteries of Japanese men. Does that mean that Americans can lower the rate of heart disease, which now carries off about a third of us, by lots more tea? Persons whose average intake of tea is several cups a day do have less heart disease but they also have a much different lifestyle than most Westerners. They live in countries where fast food outlets have been rare until very recently, their intake of fruits and vegetables is high and their consumption of red meat and processed foods is low. With fewer labor-saving devices they are more physically active, making their hearts stronger and their blood pressure lower.
Women who drink 5 or more cups of green tea daily have a lower risk of breast cancer. Only 8 percent of Americans drink that much green tea in a week and my guess is that most of them are of Asian heritage.
Does the caffeine in tea play any role? Not likely. The amount of caffeine in a cup a tea varies widely depending on the type of tea and the time allowed for it to steep. Still, the average cup of tea as it is brewed in this country has about half as much caffeine as the typical cup of coffee. Coffee contains beneficial antioxidants but caffeine itself seems to be devoid of health benefits. On the other hand, it is no villain, either. After decades of investigation caffeine has no proven harmful effects except for coffee jangles.
The bottom line is that drinking 3 or 4 American-sized cups of tea, green or otherwise, every day may be slightly protective against heart disease, cancer, diabetes and stroke. Tea is cheaper than coffee, especially those oversized coffeehouse specialties, and it has absolutely no harmful side effects.
What are you waiting for, Starbuck's?
Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at drphil@stoneagedoc.com.