The Bulletin

Green tea may contain compounds that dramatically boost the body’s ability to fight toxins capable of causing cancer, according to a study funded by the National Cancer Institute.

Researchers at the Arizona Cancer Center found that concentrated chemicals, known as catechins, derived from green tea increased production of detoxification enzymes in people with low levels. The study had 42 people consume a concentrate of catechins equal to the amount in eight to 16 cups of green tea. They found the concentrate boosted a family of detoxification enzymes by as much as 80 percent in some test subjects.

The enzymes are believed to modify cancer-causing molecules that would otherwise damage cellular DNA.

“They actually convert known carcinogens to non-toxic chemicals, and studies have shown a correlation between deficient expression of these enzymes and increased risk of developing some cancers,” says Dr. Sherry Chow, an associate professor at the University of Arizona and lead author of the study.

The researchers said genetic variations and environmental factors leave some people with low levels of these cancer-fighting enzymes. Green tea catechins could make up for that shortfall.

Researchers found that the concentrate was most effective boosting enzyme production in those who had the lowest levels at the start of the study. Those with moderate or high levels of the enzyme at the start of the study showed little effect.

Green tea has long been suspected of having cancer-fighting properties. Countries with high green tea consumption, such as China and Japan, have lower rates of cancer. The National Cancer Institute is funding a number of studies testing capsules of green tea extract prepared in Japan to meet exact specifications. The pills contain epigallocatechin gallate (EGCG), a catechin known for its potent antioxidant activity. The studies are testing its effect against a variety of cancers.

“This is the first clinical study to show proof that chemicals in green tea can increase detoxification enzymes in humans,” Chow said. “There may be other mechanisms in play by which green tea may protect against cancer development, but this is a good place to start.”

A cup of power

Scientists have long suspected that green tea has cancer-fighting properties. A new study using green tea extract supports that claim.