Headlines announcing a recent Journal of the American Medical Association study linked consumption of green tea with protection from stroke, but not cancer, caught many people by surprise. Tea provides a good example of why we need to consider both laboratory and population studies in choosing steps to lower cancer risk and promote overall health.

Green tea contains relatively high amounts of a type of phytochemical called EGCG, proven in laboratory studies to be a powerful antioxidant. A variety of antioxidants from plant foods seem to stabilize “free radicals,” protecting DNA from damage that could allow cancer to develop, and protecting blood vessels from damage that could promote blockages. Studies show EGCG can also increase production of enzymes that protect us from cancer-causing substances, decrease levels of a substance key to promoting cancer development, and increase cancer cell self-destruction.

In most studies checking signs of green tea’s effects in people, antioxidant levels in the blood increase, showing we can absorb antioxidant compounds in tea.

Do benefits of soy decrease protection of tea?

Benefits in the effects seen in tea drinkers may come from other healthy habits. Differences of study findings may also mean green tea offers more benefit for some people than others, depending on diet or exposure to risk-producing substances such as tobacco or pollution. One study, for example, suggests tea and soy may produce similar benefits, and consuming one may decrease the chances

of benefit from the other. That might explain why cancer protection was not seen in the recent study of Japanese adults, almost all of whom ate soy foods daily.

report excerpted from MSNBC.com