Green Tea Unlikely to Prevent Breast Cancer

Kathleen Blanchard's picture
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Despite the multitude of health benefits associated with green tea, new research finds the popular beverage is no help when it comes to preventing breast cancer. The results come from researchers who examined databases of 54,000 Japanese women in a prospective cohort study.

The research was conducted to find out green tea consumption might explain the lower incidence of breast cancer in Asian, compared to Western countries, that has been hypothesized and supported by in vitro animal studies.

The study authors note, “…few epidemiological studies have examined the association between green tea intake and risk of breast cancer, and their findings have been inconsistent.”

Women age 40 to 59 years were recruited in the Cohort I study and women age 40 to 69 years were included in Cohort II. The study began in 1990 via questionnaires. Women with a history of cancer at baseline and at five year follow-up were excluded from the study.

Green Tea Failed to Prevent Breast Cancer in Final Analysis

The final analysis showed no association between green tea intake and fewer incidences of breast cancer, even for women with high intake of the beverage.

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The amount and type of green tea intake was tracked, in addition to the women’s consumption of oolong tea, black tea, and coffee. The study participants were followed until 2006 by way of cancer reporting registries, notification from hospitals and death certificates that supplied supplemental information about breast cancer incidence.

A strength of the study according to the authors was the inclusion of women who drank as little as 1 cup a day and as many as 10 cups.

The sample of women was large, and the participants were recruited before breast cancer diagnosis, making recall bias less likely, but the researchers say it’s possible there may have been variances in how much tea the women reported and actually drank throughout the study.

The conclusion from the study authors is, “Our findings suggest that drinking green tea as a beverage is unlikely to reduce the risk of breast cancer regardless of green tea type and number of cups within a usual drinking habit.”

Despite promising findings in vitro animal studies, researchers found no benefit for breast cancer prevention in the large study of Japanese women who reportedly drank anywhere from one to ten cups of green tea daily.

Cancer Research

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