Green tea provides significantly more health benefits than black tea due to its higher content of free polyphenols. The major polyphenols in green tea are flavonoids, the most active of which is epigallocatechin gallate. In addition to serving as antioxidants, green tea polyphenols may increase the activity of antioxidant enzymes in the small intestine, liver, and lungs. A number of experiments conducted in test-tube and animal cancer models have shown that green tea polyphenols inhibit cancer by blocking the formation of cancer-causing compounds, such as nitrosamines, suppressing the activation of carcinogens, and detoxifying or trapping cancer-causing agents. The forms of cancer that appear to be best prevented by green tea are cancers of the gastrointestinal tract, including cancers of the stomach, small intestine, pancreas, and colon; lung cancer; estrogen-related cancers, including most breast cancers; and prostate cancer. Although important in fighting all of these cancers, green tea is especially important in preventing breast and prostate cancers.
In contrast to green tea's protective effects, population studies seem to indicate that black tea consumption may increase the risk of certain cancers, including cancer of the rectum, gallbladder, and endometrium.
More Answers from Michael T Murray