FRIDAY, Oct. 29 (HealthDay News) -- Although animal and in vitro studies have shown green tea to be protective against breast cancer, a large prospective trial in Japan has found no such benefit; the findings have been published online Oct. 28 in Breast Cancer Research.
Motoki Iwasaki, M.D., of the National Cancer Center in Tokyo, and colleagues studied data on green tea intake and breast cancer incidence in 53,793 women to investigate the possible link between green tea drinking and breast cancer.
The researchers found no inverse relationship between green tea consumption and breast cancer incidence regardless of green tea type, menopausal status, or hormone receptor subtype; the adjusted hazard ratio was 1.12 for women who drank five or more cups of green tea per day compared with women who drank less than one cup of green tea per week (P for trend = 0.60).
"Our findings are in general agreement with those of three prospective studies, including two Japanese cohort studies, which found no association between green tea intake and breast cancer risk. One noteworthy strength of the present over previous studies is the remarkably wide variation in green tea intake, from women who drank green tea less than one cup per week to those who drank 10 or more cups per day," the authors write.