March 14, 2009
Green Tea, Mushrooms May Reduce Risk Of Breast Cancer
A new Australian study finds that women whose diets include plenty of green tea and mushrooms may have a lower risk of developing breast cancer.
The study, which involved more than 2,000 Chinese women, found that the more fresh and dried mushrooms the women consumed, the lower their breast cancer risk. The risk was lowest in women who also drank green tea everyday.
Rates of breast cancer among Chinese women is four to five times lower than those typically seen in Western nations, although that has been changing in recent years within China's wealthier areas.
The current research suggests that traditional diets, particularly those including plenty of mushrooms and green tea, may help explain China's lower breast cancer incidence, said Dr. Min Zhang of the University of Western Australia in Perth, the study's lead researcher.
Dr. Zhang and her colleagues conducted the study in southeast China with 1,009 breast cancer patients aged 20 and 87 years old and an equal number of healthy women of the same age. All completed a comprehensive dietary survey that asked them how often they ate certain foods.
The researchers found that women who consumed the most fresh mushrooms, 10 grams or more daily, were roughly two thirds less likely to develop breast cancer than those who consumed no mushrooms. Furthermore, those who ate 4 grams or more of dried mushrooms daily halved their cancer risk compared with women who ate no mushrooms.
The results showed that mushroom eaters who also consumed green tea everyday had only 11-18 percent the risk of breast cancer of women who consumed neither. However, the researchers emphasize that the study does not prove a cause-and-effect relationship.
The study accounted for various breast cancer risk factors, such as education level, weight, exercise frequency and smoking status, but there could be other factors at work that might explain the findings.
The study is the first to link high dietary amounts of green tea and mushrooms to a reduction in breast cancer risk, Zhang said in an interview with Reuters.
Therefore, it's premature for women to assume that consuming these foods will help them prevent breast cancer, she said.
However, it is biologically plausible, according to the researchers.
Previous lab studies have demonstrated that mushroom extracts contain anti-tumor properties, which in animals can stimulate the immune system's cancer defenses. And green tea contains antioxidant compounds known as polyphenols, which have been shown to fight breast tumors in animals.
Dr. Zhang and her colleagues published a report about the findings in the International Journal of Cancer. An abstract can be viewed at http://www3.interscience.wiley.com/journal/121428129/abstract.