There is some evidence that the antioxidant polyphenols found in green and black tea may protect against certain cancers. Researchers have proposed that these polyphenols reduce the risk of developing cancer by inhibiting cancer cell growth and/or killing cancer cells. But research examining the association between tea consumption and cancer risk has been limited.

A new study in the December 12/26, 2005 issue of the Archives of Internal Medicine followed a group of women for 15 years and found that drinking two or more cups of tea per day was associated with a significant reduction in the risk of developing ovarian cancer .

About the Study

This study included 61,057 Swedish women ages 40-76. The women filled out a food-frequency questionnaire that included tea consumption. Researchers followed the women for about 15 years, tracking who developed ovarian cancer. The researchers examined the association between tea consumption and the development of ovarian cancer. They adjusted their analyses for other factors associated with ovarian cancer, including body mass index (a measure of weight in relation to height), oral contraceptive use, and diet.

Sixty-eight percent of the women reported drinking tea at least once per month, and 301 women were diagnosed with ovarian cancer during the study. Drinking two or more cups of tea per day was associated with a 46% reduction in the risk of developing ovarian cancer. And each additional cup of tea per day was associated with an 18% reduction in the risk of developing ovarian cancer.

This study was limited because tea consumption was measured with a food frequency questionnaire, which is subject to error.

How Does This Affect You?

These findings suggest that tea consumption may reduce the risk of developing ovarian cancer. But, although the researchers controlled for some lifestyle factors associated with colorectal cancer (e.g., body mass index, diet), they may not have controlled for everything. It is possible that tea drinkers live more healthful lifestyles overall, which may affect their risk of developing cancer. Also, ovarian cancer is rare (only 0.49% of women developed ovarian cancer during this 15 year study), so even though there was significant reduction in ovarian cancer risk among the women in the study, the impact of tea drinking on individual women was quite small.

More research is needed to determine the benefits of tea consumption, and the National Cancer Institute is currently investigating the medicinal benefits of drinking tea. In the meantime, if you drink tea, continue to enjoy it with the knowledge that it may be reducing your risk of cancer.