Green Tea & Colorectal Cancer
Much has been written about the potential anti-cancer effects of green tea, including the many research studies that I have reviewed in this column (please see my archives, below). A new research study, just published in the journal Gastroenterology, adds additional important information to our understanding about the effects of green tea, and its active ingredients, on the development and progression of cancer.
Researchers from the University of Tennessee performed several interesting experiments using epigallocatechin-3-gallate, the predominant active compound in green tea. This extract of green tea was first applied to human colorectal cancer cells growing in a culture dish. A series of complex laboratory tests determined that the green tea extract significantly reduced the presence of the protein basic fibroblast growth factor, which has been implicated, along with several other proteins, in tumor cell growth and spread (metastasis).
In the second part of this study, mice with a genetic defect that results in a 100% risk of colorectal cancer had their diet supplemented with the green tea extract (while a control group of similar mice did not receive this supplement). Once again, the researchers found that the mice treated with the green tea extract had decreased levels of basic fibroblast growth factor in their colorectal tumor cells. Moreover, supplementation with green tea extract resulted in considerably fewer colorectal tumors when compared with the mice that did not receive the extract.
The results of this study provide intriguing insight into the potential caner prevention effects of green tea, and at the molecular level. Several human clinical trials are already underway, looking at the effects of green tea on cancer prevention and cancer treatment. As we have seen with other areas of clinical research, what works in Petri dishes and laboratory mice doesn’t always translate well to humans. It will be interesting to see what the long-term results of ongoing human green tea clinical trials will tell us about the potential disease prevention and therapeutic effects of green tea.