Green tea is known to have many health giving properties. One of theses is in the prevention of breast cancer. This is thought to be due to the polyphenols that are present in green tea. Much research has been carried out on these tea polyphenols with positive experimental models results in the labs. However, most of the studies that have been carried out in real life populations have not shown a link between tea consumption and breast cancer. This could be as a consequence of most of the data being on western women, who are more likely to drink black tea than green tea.

Even though black tea has many health benefits through its antioxidant properties, the way that it is manufactured means that it has a different biochemical composition than that of green tea.

Many of the studies that have been carried out in the link between green tea and breast cancer have led to inconclusive results; studies of Chinese women in Singapore finding a positive effect between green tea consumption and breast cancer, whereas studies in Japan have shown no correlation.

Green Tea and Black Tea Differences

Green tea is the main form of tea that is consumed in Japan and most of China varies from black tea in the way that it is produced. In the manufacture of Black tea the tea is allowed to oxidize (and hence becomes black) whereas green tea is not allowed to oxidize.

This means that the two beverages have many different properties, and though they both have antioxidant properties, the antioxidants found in green tea tend to be monomeric polyphenols whereas in black tea they are partially polymerised.

Green tea has been produced and consumed in China for thousands of years. It therefore makes it an ideal place to look for any relationship between green tea consumption and breast cancer, and to investigate why Chinese women have much lower breast cancer incident rates than women. The next section of this article goes on to look at a research paper by Zhang et al from Zhejiang university that looks into the relationship of green tea consumption and prevention of breast cancer in the S.E. of China.

Green tea and breast cancer (part 2)

References
Zhang et al (2006) Green tea and the prevention of breast cancer: a case-control study in South east China. Carcinogenesis 28: 1074 to 1078
Bray,F. et al. (2004) The changing global patterns of female breast cancer incidence and mortality. Breast Cancer Res., 6: 229 to 239.
Wu,A.H. et al. (2003) Green tea and risk of breast cancer in Asian Americans. Int. J. Cancer, 106: 574 to 579.
Nagano,J. et al. (2001) A prospective study of green tea consumption and cancer incidence, Hiroshima and Nagasaki (Japan). Cancer Causes Control, 12: 501 to 508.