Green Tea, Cancer Prevention Link Unclear

WASHINGTONA large new Cochrane review of studies focused on the relationship between green tea consumption and a variety of cancers, including breast, lung, digestive tract, urological prostate, gynecological and oral cancers, yielded conflicting results.

Researchers looked at 51 medium- to high-quality studies conducted from 1985 to 2008 that included more than 1.6 million participants. Many of the reviewed studies took place in Asia, where tea drinking is widespread and part of the daily routine for many.

The review, which appears in the latest issue of The Cochrane Library, found that green tea had limited benefits for liver cancer, but found conflicting evidence for other gastrointestinal cancers, such as cancer of the esophagus, colon or pancreas. One study found a decreased risk of prostate cancer for men who consumed higher quantities of green tea or its extracts.

The review did not find any benefit for preventing death from gastric cancer, and found that green tea might even increase the risk of urinary bladder cancer. Despite conflicting findings, there was limited moderate to strong evidence of a benefit for lung, pancreatic and colorectal cancer. None of the studies that simply observed a group of people over time found a benefit for breast cancer prevention. However, both of the case control studieswhich compare people without a condition to people with itfound a positive association between green tea consumption and a decreased risk of breast cancer.