title: Dietary antioxidants and ozone-induced bronchial hyperresponsiveness in adults with asthma.
abstract: Ozone exposure aggravates asthma, as has been demonstrated in both controlled exposures and epidemiologic studies. In the current double-blind crossover study, the authors evaluated the effects of dietary antioxidants (i.e., 400 IU vitamin E/500 mg vitamin C) on ozone-induced bronchial hyperresponsiveness in adult subjects with asthma. Seventeen subjects were exposed to 0.12 ppm of ozone or to air for 45 min during intermittent moderate exercise. Bronchial hyperresponsiveness was assessed with 10-min sulfur dioxide (i.e., 0.10 ppm and 0.25 ppm) inhalation challenges. Subjects who were given dietary antioxidants responded less severely to sulfur dioxide challenge than subjects given a placebo (i.e., forced expiratory volume in the 1st sec: -1.2% vs. 4.4%, respectively; peak flow: +2.2% vs. -3.0%, respectively; and mid-forced expiratory flow: +2.0% vs. -4.3%, respectively). Effects were more pronounced when subjects were grouped by response to sulfur dioxide at the screening visit. The results suggest that dietary supplementation with vitamins E and C benefits asthmatic adults who are exposed to air pollutants.
authors.affiliation: Department of Environmental Health, University of Washington, Seattle 98195-7234, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Trenga
authors.forename: J Q
authors.initials: JQ
authors.lastname: Koenig
authors.forename: P V
authors.initials: PV
authors.lastname: Williams
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects*; D000403:Airway Resistance / Q000187:drug effects; D000975:Antioxidants / Q000494:pharmacology* / Q000627:therapeutic use*; D001205:Ascorbic Acid / Q000494:pharmacology / Q000627:therapeutic use; D001249:Asthma / Q000139:chemically induced / Q000517:prevention & control*; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D010126:Ozone / Q000009:adverse effects*; D013458:Sulfur Dioxide; D014810:Vitamin E / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000393:Air Pollutants; D000975:Antioxidants; D013458:Sulfur Dioxide; D014810:Vitamin E; D010126:Ozone; D001205:Ascorbic Acid