Green Tea May Reduce Lung Cancer Risk—Even for Smokers

For thousands of years, the people of China, Japan, India, and Thailand have consumed green tea and used it medicinally to treat everything from headaches to flatulence. In fact, the ancient Chinese proverb, “better to be deprived of food for three days, than tea for one,” gives us an idea of how much they believed in its curative abilities. Over the past few decades, however, research in both Asia and the West has begun providing scientific evidence of green tea’s numerous health benefits.

As a whole, studies indicate that regular consumption of green tea may slow or prevent conditions including high cholesterol, heart disease, rheumatoid arthritis, impaired immune disease and liver disease. In addition, some studies have indicated green tea may have cancer-fighting properties [1], lowering the rate of gastric, esophageal, and mouth cancers. And in a conference this week sponsored by the American Association for Cancer Research (AACR) and the International Association for the Study of Lung Cancer (IASLC), researchers reported that Taiwanese smokers who consumed one cup of green tea each day significantly reduced their chances of developing lung cancer.

For their study, Dr. I-Hsin Lin, of Chung Shan Medical University in Taiwan, and her colleagues recruited 170 people with lung cancer and 340 healthy patients as controls. The participants completed questionnaires regarding their lifestyle habits, including how much they smoked, how much green tea they drank, their dietary intake of fruits and vegetables, cooking practices and family history of lung cancer. They also underwent genotyping on insulin-like growth factors: IGF1, IGF2, and IGFBP3, all of which have been reported to be associated with cancer risk.

The results showed that both smokers and non-smokers who did not drink green tea were 5 times more likely to develop lung cancer compared to those who drank at least one cup of green tea per day. Smokers who did not drink green tea at all were more than 12 times more likely to be diagnosed with lung cancer than those who drank at least one cup of green tea per day. However, the protection was greatest for those carrying certain genes [2]. Green tea drinkers, whether smokers or non-smokers, with non-susceptible IGF1 (CA)19/(CA)19 and (CA)19/X genotypes reported a 66 percent reduction in lung cancer risk compared with green tea drinkers carrying the IGF1 X/X genotype.

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Lin explained that green tea’s cancer-fighting benefits are due to its rich concentration of chemicals called polyphenols, notably a catechin called as epigallocatechin-3-gallate (EGCG), which acts as a powerful antioxidant. “Tea, particularly green tea, has received a great deal of attention because tea polyphenols are strong antioxidants, and tea preparations have shown inhibitory activity against tumorigenesis,” she said. “Our study may represent a clue that in the case of lung cancer, smoking-induced carcinogenesis could be modulated by green tea consumption and the growth factor environment.”

But cancer experts say the findings don’t change the fact that smoking [3] is bad for health and shouldn’t be used as an excuse to continue smoking. “Smoking tobacco fills your lungs with around 80 cancer-causing chemicals. Drinking green tea is not going to compensate for that,” said Yinka Ebo, of Cancer Research UK. “Unfortunately, it’s not possible to make up for the harm caused by smoking by doing other things right like eating a healthy, balanced diet. The best thing a smoker can do to reduce their risk of lung cancer, and more than a dozen other cancer types, is to quit.”

More people, both male and female, die from lung cancer than from any other type of cancer. In 2005 (the most recent year for which statistics are available), 196,687 people in the United States were diagnosed with lung cancer, and 159,217 died from it. About 90 percent of lung cancer deaths in men and almost 80 percent of lung cancer deaths in women are due to smoking.