'One thing is certain: green tea consumption can never account for cancer prevention alone,' said Boehm.

The review 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, said a release of the Oncology Study Group.

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.

The review appeared in a recent issue of The Cochrane Library.