A study published in Cancer Epidemiology, Biomarkers and Prevention found that women who regularly drank green tea, lowered their risk of developing both colon and rectal cancers compared with women who drank green tea infrequently or not at all.
More than 69,700 Chinese women between the 40 and 70 years old were enrolled in the study regarding their tea consumption. The women were followed for a total of six years. In that time, 256 cases of colorectal cancer were identified.
Scientists found:
"A significant dose-response relationship was found for both the amount of tea consumed and duration in years of lifetime tea consumption. The reduction in risk was most evident among those who consistently reported to drink tea regularly at both the baseline and follow-up surveys. This study suggests that regular consumption of green tea may reduce CRC risk in women."
One thing to bear in mind is that all the women in the study were Chinese and Chinese people typically have lower rates of cancer than Western people, so this should be considered when interpreting the results. However, the fact that Chinese people do consume a lot of green tea may be one of the reasons why they get less cancer. They were also compared with their own race and rates of cancer in frequent tea drinkers were lower than the rate normally seen in Asian countries.
The fact that the study was performed with such a large group of women and they were followed for a long period of time, makes it statistically significant.
It would be worthwhile for the community if the medical profession would conduct more studies into the benefits of green tea and its anti-cancer properties for people who live in the U.S. or UK to see if there are any variations in rates.
In the meantime, start drinking green tea today for a healthier future (don't add sugar as this depresses the immune system and could counter the effect). One or two cups a day as part of your diet could reduce your risk of cancer and certainly won't harm you.
Source: Yang, G. and Shu, X. "Prospective Cohort Study of Green Tea Consumption and Colorectal Cancer Risk in Women." Cancer Epidemiology Biomarkers & Prevention 16 (1 Jun. 2007): 1219-1223.