There are hundreds, perhaps thousands, of scientific papers researching tea, but the results are often split. While one study might find that tea boosts immune function, another often shows no effect. The research is hampered by the fact that most of the studies have examined effects on animals, and little research has been done on the differences between various types of tea.
Nonetheless, a growing number of studies have suggested potential health benefits from tea, and this has attracted a great deal of interest. Research has indicated that tea could have beneficial effects including:
In 2006, a Japanese company petitioned the FDA for permission to label green tea as offering protection against heart disease. The agency denied the request, saying that the research on the subject was "supportive but not conclusive."
One component of tea, epigallocatechin gallate (EGCG), could help prevent psoriasis, prostate cancer and colon tumors. It is now being used as an ingredient in health foods, beverages and dietary supplements.The Washington Post July 17, 2007
2.25 billion gallons of tea -- about 132 cups of tea per person per year -- is consumed in the United States. However, people in China, Japan and other parts of Asia often drink multiple cups per day.
There is some pretty compelling evidence that the polyphenols in green tea are more effective at fighting the progression of cancer than the antioxidants found in red wine, grapes and peanuts. In addition, the EGCG (epigallocatechin gallate) in tea could be another useful cancer-prevention tool.
But the health benefits of tea are still ripe for discussion, with some studies showing positive results and others finding no effect. Even studies yielding positive results seem to show that you may actually need five to 10 cups per day in order to reap these benefits -- and it's also not yet clear whether or not decaf varieties work as well.Since tea contains about half the caffeine found in coffee, it can really add up. Caffeine comes with its own set of problems, including its ability to worsen insulin sensitivity, which is a major cause of chronic illness.