The latest issue of the journal Gastroenterology contains an article about how green tea can prevent colorectal cancer.
The chemistry involved is complex, but it basically breaks down like this:
The green tea antioxidant epigallocatechin-3-gallate (EGCG) interferes with the production of basic fibroblast growth factor (bFGF). Normal cells use bFGF to form blood vessels, but cancer cells produce it in excessive amounts to reproduce and spread (metastasize) to other parts of the body.
So, by impeding the overproduction of bFGF by cancer cells, EGCG stops cancer in its tracks.
In other words, green tea may be the beverage of mellowness, but it gets tough when it comes to cancer.
Cover of the issue of Gastroenterology containing the linked-to article about green tea and colorectal cancer.