Eating soy foods such as tofu, soybeans, and soy milk may help reduce the risk of developing lung cancer in non-smokers, according to a new study in the Jan 13, 2010 issue of American Journal of Clinical Nutrition.
The study shows an inverse association between intake of isoflavone, a component found high in soybeans and the lung cancer risk in both female and male non-smokers.
Non-smokers were defined as those who have never smoked in the study.
Early case-control studies have already revealed a similar association. But this may be the first prospective cohort study confirming that eating soy may cut the risk.
For the study, Shimazu T and colleagues at the National Cancer Center in Tokyo, Japan followed 36,177 men and 40,484 women aged 45 to 74 years who were not diagnosed with lung cancer when entering the study in 1995 to 1999.
The participants were surveyed at baseline through a validated 138-food-item questionnaire. During the 11-year follow-up, 481 men and 178 women were diagnosed with lung cancer.
Of the never-smoking men, those who had their intake of isoflavone in the highest quartile were 57 percent less likely to be diagnosed with lung cancer than those who had the lowest quartile of the phytochemical, the researchers found.