Tea and Cancer

Tea and Cancer
Most of the on cancer chemoprevention by tea has been conducted using green tea or its individual polyphenolic constituents.

Less work has been reported on black tea.

In animal studies, the polyphenolic fraction isolated from green tea. The water extract of green tea, or individual polyphenolic antioxidants present in green tea have afforded protection against chemically induced carcinogenesis in the lung, liver, esophagus, forestomach, duodenum, pancreas, colon, and breast.

The raises possibility that green tea consumption and its associated catechins may lower cancer risk in humans.

Studies have shown that green tea intake increases the excretion of a class of carcinogens known as heterocyclic arylamines formed during the cooking of meat, poultry and fish; this is expected to reduce DNA adduct formation, in particular and carcinogenesis, in general.

Consumption of both green and black tea aqueous extracts influences the excretion of mutagens and promutagens in the urine of animals.

Several epidemiological studies suggest that tea and its associated compounds may prevent some, but not all, cancers.

This is understandable, because cancer is a complex disease with multiple etiologies, even for one body site.

It is, therefore a false hope that any nutritional or synthetic agent can prevent or treat all cancer types.

However, based on a large volume of cell culture, animal studies and human observational studies, there is hope that green tea consumption can retard cancer development at selected sites in some populations.

The challenge is to elucidate what cancer type can be prevented by tea. This requires extensive research for which considerable resources are required.
Tea and Cancer