Tea and cancer

There are teas and there are teas. But the original one and only tea is from the plant Camelia sinensis.

According to the American Botanical Council

“…the tea plant is a small, evergreen shrub with white flowers that is native to mountainous regions of China, Japan, and India. It is cultivated around the world in countries with tropical and subtropical climates. While the plant can get as tall as 30 feet, it is usually pruned to 2-3 feet. The young leaves and the dried leaf bud are used and are considered to have a better quality than the older leaves. Tea types (green tea, black tea, oolong tea, etc.) vary based on the way the tea leaves are processed.”

Tea has been used over the ages as a beverage with medicinal use. Here are some recent clinical trials on the effects of tea on the risk for different kinds of cancer.

Prostate cancer

Japanese researchers conducted a study on the effect of green tea on the prevention of prostate cancer. They did not found an association between green tea consumption and localized prostate cancer. However, “consumption was associated with a dose-dependent decrease in the risk of advanced prostate cancer” This probably explains why the incidence of prostate cancer in Asian men is much lower than among Western men.

Bladder cancer

In another Japanese study, researchers evaluated the link between caffeine from tea and coffee on the incidence of bladder cancer. Results of this prospective study show that caffeine may be associated with increased risk of bladder cancer among smoking men. Cigarette smoking is a confirmed risk factor for bladder cancer.

Pancreatic cancer

Yet another Japanese study looked at the effect of green tea consumption on the risk of having pancreatic cancer. The study findings “do not support the hypothesis that green tea consumption is associated with decreased risk of pancreatic cancer in humans.”

Breast cancer

This prospective study conducted by Harvard researchers assessed the impact of caffeine consumption on breast cancer risk. The results show that there is “no overall association between caffeine consumption and breast cancer risk.” There is however, “a possibility of increased risk in women with benign breast disease or for tumors that are estrogen and progesterone receptor negative or larger than 2 cm” which requires more investigation.

In another long-term study on caffeine – breast cancer link, Harvard researchers followed women for 22 years. The results found no significant association between consumption of coffee (caffeinated and decaffeinated) and tea and risk of breast cancer. However, there is a weak inverse association between caffeinated drinks and risk of postmenopausal breast cancer.

Endometrial cancer

Another Japanese study investigated the effect of green tea consumption and the risk of endometrial cancer of endometrial endometrioid adenocarcinoma (EEA) type only. The researchers “observed a significant inverse association between green tea consumption and the risk of EEA with a dose-response relationship…This inverse association was consistently observed regardless of the presence or absence of factors such as obesity and menopause… Green tea consumption may be associated with a lower risk of EEA.”

The moral of these stories: It seems that tea might reduce risks for some cancers but not for others. However, it looks like it’s safe to give tea as a Christmas present!

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