New evidence suggests that drinking black tea and caffeinated coffee daily may be associated with a lower risk of endometrial cancer in women. Endometrial cancer affects the lining of the uterus and is most common among women who are between the ages of 60 and 70.
Researchers surveyed 1,100 women about their consumption of black tea, decaffeinated coffee and caffeinated coffee. Half of the women were diagnosed with endometrial cancer.
They found that women who drank more than four cups of coffee and tea daily were about 50 percent less likely to develop endometrial cancer. Women who drank more than two cups of black tea daily were about 44 percent less likely to develop the disease. Additionally, women who drank more than two cups of coffee daily were 29 percent less likely to develop cancer, although this trend was not statistically significant.
It is unclear how black tea and coffee may help prevent endometrial cancer. The authors suggest that the results may be attributed to caffeine because decaffeinated coffee was not linked to a decreased cancer risk.
Laboratory and animal studies report that components of black tea, such as polyphenols, have antioxidant properties and effects against tumors. However, effects in humans remain unclear.
http://www.ncbi.nlm.nih.gov/pubmed/19107932?dopt=Abstract