title: Dietary intake of soy genistein is associated with lung function in patients with asthma.
abstract: To determine if micronutrient intake is associated with asthma severity, we administered the Block food frequency questionnaire to participants in a randomized clinical trial of the safety of influenza vaccine for asthmatics. The nutrition substudy included 1033 participants, aged 12-75. Intake of antioxidant vitamins, soy isoflavones, total fruits and vegetables, fats, and fiber was compared with asthma severity at baseline [forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEF), asthma symptoms] and the rate of asthma exacerbations during the 2 weeks following influenza vaccination. The only nutrient that had a consistent association with asthma severity was genistein, a soy isoflavone. None of the nutrients evaluated were related to asthma exacerbation rate when adjusted for known confounders. The FEV1 in genistein consumers of at least 250 microg/1000 Kcal/day was 82.1% predicted, 79.9% predicted for those who consumed between 1 and 249 microg/1000 kcal, and 76.2% predicted in genistein nonconsumers (p=0.006); the PEF was 82.7% predicted, 80.8% predicted, and 78.3% predicted, respectively (p=0.009). There were no differences in the Asthma Symptom Utility Index (ASUI). We could not account for these results based on differences in demographics, body mass index, or consumption of other nutrients. Thus, increasing consumption of genistein is associated with better lung function in patients with asthma. Further studies are needed to determine whether dietary supplementation with genistein can reduce asthma severity.
authors.affiliation: Feinberg School of Medicine, Northwestern University, Evanston, Illinois, USA. ljsmith@northwestern.edu
authors.forename: Lewis J
authors.initials: LJ
authors.lastname: Smith
authors.forename: Janet T
authors.initials: JT
authors.lastname: Holbrook
authors.forename: Robert
authors.initials: R
authors.lastname: Wise
authors.forename: Malcolm
authors.initials: M
authors.lastname: Blumenthal
authors.forename: Allen J
authors.initials: AJ
authors.lastname: Dozor
authors.forename: John
authors.initials: J
authors.lastname: Mastronarde
authors.forename: Larry
authors.initials: L
authors.lastname: Williams
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000503:physiopathology*; D002648:Child; D004032:Diet; D005260:Female; D019833:Genistein / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D012129:Respiratory Function Tests; D011795:Surveys and Questionnaires
chemical_list: D019833:Genistein