Soy Supplement Did Not Improve Asthma Symptoms

Lewis J. Smith, MD Professor of Medicine and Associate Vice President for Research Northwestern University and the Feinberg School of Medicine Chicago, IL 60611MedicalResearch.com Interview with:
Lewis J. Smith, MD

Professor of Medicine and Associate Vice President for Research
Northwestern University and the Feinberg School of Medicine
Chicago, IL 60611

Medical Research: What is the background for this study? What are the main findings?

Dr. Smith: We previously observed in a survey of more than 1,000 patients with asthma that those consuming soy isoflavones in their diet had better lung functioning than their counterparts who consumed little or none.  Using a more detailed soy questionnaire, we confirmed the observation in a different group of patients with asthma, and followed that up with laboratory studies.  In cell culture studies, we saw that genistein, the major soy isoflavone, at levels that are achieved in individuals consuming a high soy diet, reduces eosinophilic inflammation, a key feature in asthma. In addition, people who consume more soy products, mostly in Japan and parts of China, generally have less asthma than in western countries.  Although these data indicate a potential beneficial effect of soy isoflavones in patients with asthma and nutritional supplements are commonly used by people to treat and prevent disease and improve their health, there was little direct data to prove that the supplement is actually effective.  As a result, we explored the effects of a soy isoflavone supplement in 386 adults and children aged 12 or older with poorly controlled asthma. All were taking medicine to treat their asthma – either corticosteroids or leukotriene modifiers – but none consumed soy more than once a week. In the randomized, double-blind study, half of the participants took a soy isoflavone supplement twice daily for six months, and the other half took a placebo. We found that the supplement, though able to increase blood levels of genistein, did not improve lung function, symptoms or measures of inflammation in these individuals.

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Prostate Cancer: Soy Supplementation Did Not Reduce Recurrence

Maarten C. Bosland, DVSc, PhD Professor of Pathology Department of Pathology University of Illinois at Chicago College of Medicine Chicago, IL  60612MedicalResearch.com Interview with:
Maarten C. Bosland, DVSc, PhD

Professor of Pathology
Department of Pathology
University of Illinois at Chicago
College of Medicine
Chicago, IL  60612

MedicalResearch.com: What are the main findings of the study?

Dr. Bosland: Daily consumption of a supplement containing soy protein isolate for two years following radical prostatectomy did not reduce recurrence of prostate cancer in men at high risk for this (radical prostatectomy is surgical removal of the prostate to treat prostate cancer). The study showed that this soy supplementation was safe. It is not clear whether this result indicates that soy does not prevent the development of prostate cancer, but men that have the disease probably do not benefit from soy supplementation.
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