Green tea could reduce lung cancer risk for smokers and non-smokers
Researchers from Taiwan have compared smokers to non-smokers, finding that smokers who drink one cup of green tea daily have a lower risk of lung cancer. Drinking green tea was also found to reduce lung cancer risk for non-smokers.
The scientists found that smokers who do not have a cup of green tea daily showed a 12.71 percent increased risk of lung cancer compared to individuals who smoke but drink one cup of green tea daily. Compared to individuals who consume the beverage, the risk of lung cancer was 5.61 percent higher regardless of smoking status.
"Lung cancer is the leading cause of all cancer deaths in Taiwan," said I-Hsin Lin, M.S., a student at Chung Shan Medical University in Taiwan. "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." Past studies that have been poorly controlled have failed to prove that green tea reduces cancer risk, leading scientists to inconclusive evidence about whether green tea really does reduce cancer risk.
The scientists studied 340 healthy individuals and 170 people with lung cancer. Questionnaires were used to determine smoking status, dietary intake of fruits and vegetables, green tea consumption, cooking habits, and family history of lung cancer. The influence of drinking green tea and reduced risk of lung cancer was found by genotyping of insulin like growth factors IGF1, IGF2 and IGFBP3 that are associated with the development of lung cancer.
Among the study participants without genetic susceptibility to lung cancer, a 66 percent reduced risk of developing the disease was associated with drinking one cup of green tea daily, compared to study participants who were genetically susceptible to lung cancer. "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," said Lin. Drinking one cup of green tea daily was found to modify the effects of smoking, reducing lung cancer risk for smokers and non-smokers with genetic susceptibility to the development of lung tumors in the study. Green tea can also slow growth of prostate cancer, shown in a study published last year.