Jan. 12, 2010 (Coronado, Calif.) -- Drinking a cup or more a day of green
tea may counteract the effect of smoking on lung cancer, especially in
smokers who may not be genetically susceptible to the cancer, according to a
''The antioxidants may inhibit tumor growth," I-Hsin Lin, a master's degree
student at Chung Shan Medical University in Taiwan, tells WebMD. She presented
her findings today at the American Association of Cancer Research --
International Association for the Study of Lung Cancer meeting in Coronado,
Lin found the protective effect especially evident in a group of smokers she
studied who have specific genotypes that have not been linked to cancer risk in
Lin's team evaluated 170 patients with lung cancer and 340 healthy patients.
They asked the participants to describe their cigarette smoking habits, green
tea drinking habits, and other lifestyle factors.
They asked participants to describe habits for the previous five years, Lin
The researchers performed genotyping in the participants to see if they had
any of the genotypes found in some studies to be associated with cancer risk.
These include IGF1 (insulin-like growth factor 1), IGF2, and IGFBP3.
Overall, the smokers and nonsmokers who didn't drink green tea had a more than five
times greater risk of lung cancer compared to those who had at least a cup of
green tea, Lin found.
Among the smokers, the non-green-tea drinkers had a nearly 13 times
increased risk of lung cancer compared to the smokers who drank one cup or more
of green tea per day.
Even more dramatic was the protective effect of the green tea in those who
did not have the susceptible genotypes for lung cancer, the researchers
The green tea drinkers who didn't have a genotype termed by the researchers
as susceptible had a 66% reduced risk in lung cancer compared to the green tea
drinkers who were susceptible.
Those who smoked heavily and had the susceptible genotype had an even higher
While Lin says the best way to avoid lung cancer is to stop smoking, green
tea appears to reduce risk. "Green tea can protect them from lung cancer risk,
a cup or more a day," she says.
About 23% of U.S. adults still smoke cigarettes, according to the CDC.
Nathan Pennell, MD, PhD, a doctor at the Taussig Cancer Institute at
Cleveland Clinic in Ohio, expressed caution at the findings.
He notes that "only seven smokers had one or more cups of green tea a day."
That means the majority did not drink a cup or never drank it.
''Certainly no one has shown a definitive association between drinking green
tea and lung cancer," he tells WebMD. And some antioxidants have not borne out
as cancer preventives.