Green tea: a cup a day keep cancer at bay

The last few years have seen a rush of studies that point to green tea as an eminently healthy beverage. Much of this research has focused on the apparent ability of green tea to help ward off cancer. 

Green tea is rich in phytochemicals (naturally-occurring plant substances) known as polyphenols that have antioxidant activity. This means that they have the potential to quell disease-promoting molecules
known as free radicals in the body.

In a recent study published online in the journal Carcinogenesis, the association between drinking green tea and breast cancer was assessed [1]. In this study, green tea drinkers, compared to non-drinkers, tended to consume more fruits and vegetables (probably protective for breast cancer) and to drink more alcohol (which probably increases cancer risk). In the study, these and other factors were taken into account in an attempt to make as accurate an assessment as possible regarding the actual association between drinking green tea and breast cancer.

This study found that women who consumed at least 26 ounces of green tea leaves each year had a 39 percent reduced risk of breast cancer compared to non-drinkers. Each cup of green tea is generally made with a teaspoon of leaves. Twenty-six ounces of dried leaves per year equates to only 300 cups of green tea over the course of a year-less than one each day.

This epidemiological study can never prove that green tea protects against breast cancer. However, the fact that this study took into account a number of common confounding factors strengthens its findings. Also, green tea is known to contain substances that one would expect might help to protect the body from cancer. 

One particular polyphenol in green tea that has attracted attention is epigallocatechin gallate (EGCG). EGCG has been found to have a number of cancer-protective actions in the body, including an ability to help in the deactivation of cancer-causing chemicals (carcinogens).

Taking all of this into consideration, as well as previous research linking green tea with cancer protection, there seems to be pretty good reasons to think that drinking green tea may be beneficial.

Reference:

1. Zhang M, et al. “Green tea and the prevention of breast cancer: a case-control study in southeast China.” Carcinogenesis. Dec. 20, 2006. [Epub ahead of print]