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Soy foods help prevent lung cancer in non-smokers


Monday Feb 15, 2010 (foodconsumer.org) -- 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.

soy_foods_127188587.jpgA similar inverse association was also observed in the female never-smokers.

However, there were no association between isoflavone intake and the risk of lung cancer in current smokers and past smokers.

Some other foods or dietary supplements that may help cut the lung cancer risk according to previous studies include green tea, flavonoids, vitamin d, pomegranate fruit extract and cod liver oil among others.

Lung cancer forms in tissues of the lung. The disease is diagnosed in 219,440 men and women in 2009 in the United States and killed 159,390 in the same year.

The risk factors for lung cancer include tobacco smoking, radon, asbestos, air pollution, family history of lung cancer, and personal history of lung cancer.

Early lung cancer often does not cause symptoms and when symptoms show up, changes are great that the disease is in its late stages.  Common symptoms may include coughing, breathing trouble, constant chest pain, coughing up blood, hoarse voice, fatigue, and weight loss without known causes.

Lung cancer treatments include surgery, radiation therapy, chemotherapy, and targeted therapy.

By David Liu