The Cup that Cheers

Green and black tea come from the same plant, camellia sinensis, but are processed differently. Both are rich in polyphenols, a type of antioxidant. Antioxidants protect cells from free radical damage which leads to degeneration and disease including cancer. Whereas green tea is high in catechins, black tea contains theaflavins.

A number of studies have been carried out to investigate the effects of tea on breast cancer and it seems that green tea may offer some benefit to patients.

One study found that women who regularly drank green tea had lower levels of oestrogen, a breast cancer risk factor, than women who didn't drink it while another study found that breast cancer development seemed to slow down in women who daily drank five or more cups of green tea. In animal studies green tea extracts were found to boost the effect of tamoxifen, offering potential to reduce treatment time. As the evidence suggests that a catechin found in green tea can promote the death of certain breast cancer cells, there is potential for drug development.

To date, investigations into black tea consumption have provided conflicting evidence. In two studies, women who regularly drank black tea were found to have higher levels of oestrogen compared to non-tea drinkers and another study found that pre-menopausal women drinking black tea had a reduced risk of developing certain types of breast cancer.

It is difficult to determine the optimum consumption of green or black tea as there are so many variables. Different methods of preparation, quality of tea, size of mug or cup, re-use of tea bags and steeping time all affect the nutrients in each cup. While research results so far are promising, further human studies are needed.