Green tea "benefits cancer prevention"

US scientists say the ability of green tea to fight cancer has been
underestimated.A team from New York's University of Rochester says
that chemicals contained in green tea shut down one of the key
molecules that tobacco relies upon to cause cancer.

The researchers reached their conclusions after measuring the effects
of the chemicals found in green tea on a molecule known as the aryl
hydrocarbon (AH) receptor.

Previously Dr Thomas Gasiewicz, of the university's Environmental
Health Science Center, has shown that tobacco smoke and dioxin
manipulate the molecule to cause havoc within the body.

However, along with colleagues, he discovered that two substances in
green tea inhibit AH activity. These substances are close relations
to other flavinoids that are known to help prevent cancer and are
found in broccoli, cabbage, grapes and red wine.

The study's authors found that the chemicals shut down the AH
receptor in cancerous mouse cells and early stages of their research
suggest that the same may apply to human cells.

The scientists do point out, however, that the precise way in which
green tea is metabolised in the body is crucial to its effectiveness
and laboratory results cannot necessarily be taken to assume that
drinking green tea has the same effect.

"Right now we don't know if drinking the amount of green tea that a
person normally drinks would make a difference, but the work is
giving us insight into how the proteins work," says co-investigator
and graduate student Christine Palermo.

She adds that there are "a lot of differences" between various kinds
of green tea, and that much more research is needed.

The research is published in the journal Chemical Research in
Toxicology.