1. Effect of a Soy Isoflavone Supplement on Lung Function and Clinical Outcomes in Patients With Poorly Controlled Asthma: A Randomized Clinical Trial
- Author
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Smith, Lewis J, Kalhan, Ravi, Wise, Robert A, Sugar, Elizabeth A, Lima, John J, Irvin, Charles G, Dozor, Allen J, and Holbrook, Janet T
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Complementary and Integrative Health ,Pediatric ,Lung ,Asthma ,Clinical Research ,Nutrition ,Clinical Trials and Supportive Activities ,Prevention ,Evaluation of treatments and therapeutic interventions ,6.1 Pharmaceuticals ,Respiratory ,Adolescent ,Adult ,Child ,Dietary Supplements ,Double-Blind Method ,Female ,Forced Expiratory Volume ,Genistein ,Humans ,Isoflavones ,Male ,Middle Aged ,Phytotherapy ,Plant Extracts ,Soybean Proteins ,Young Adult ,American Lung Association Asthma Clinical Research Centers ,Medical and Health Sciences ,General & Internal Medicine - Abstract
ImportanceSoy isoflavone supplements are used to treat several chronic diseases, although the data supporting their use are limited. Some data suggest that supplementation with soy isoflavone may be an effective treatment for patients with poor asthma control.ObjectiveTo determine whether a soy isoflavone supplement improves asthma control in adolescent and adult patients with poorly controlled disease.Design, setting, and participantsMulticenter, randomized, double-blind, placebo-controlled trial conducted between May 2010 and August 2012 at 19 adult and pediatric pulmonary and allergy centers in the American Lung Association Asthma Clinical Research Centers network. Three hundred eighty-six adults and children aged 12 years or older with symptomatic asthma while taking a controller medicine and low dietary soy intake were randomized, and 345 (89%) completed spirometry at week 24.InterventionsParticipants were randomly assigned to receive soy isoflavone supplement containing 100 mg of total isoflavones (n=193) or matching placebo (n=193) in 2 divided doses administered daily for 24 weeks.Main outcomes and measuresThe primary outcome measure was change in forced expiratory volume in the first second (FEV1) at 24 weeks. Secondary outcome measures were symptoms, episodes of poor asthma control, Asthma Control Test score (range, 5-25; higher scores indicate better control), and systemic and airway biomarkers of inflammation.ResultsMean changes in prebronchodilator FEV1 over 24 weeks were 0.03 L (95% CI, -0.01 to 0.08 L) in the placebo group and 0.01 L (95% CI, -0.07 to 0.07 L) in the soy isoflavone group, which were not significantly different (P = .36). Mean changes in symptom scores on the Asthma Control Test (placebo, 1.98 [95% CI, 1.42-2.54] vs soy isoflavones, 2.20 [95% CI, 1.53-2.87]; positive values indicate a reduction in symptoms), number of episodes of poor asthma control (placebo, 3.3 [95% CI, 2.7-4.1] vs soy isoflavones, 3.0 [95% CI, 2.4-3.7]), and changes in exhaled nitric oxide (placebo, -3.48 ppb [95% CI, -5.99 to -0.97 ppb] vs soy isoflavones, 1.39 ppb [95% CI, -1.73 to 4.51 ppb]) did not significantly improve more with the soy isoflavone supplement than with placebo. Mean plasma genistein level increased from 4.87 ng/mL to 37.67 ng/mL (P
- Published
- 2015