Dietary antioxidants and ozone-induced bronchial hyperresponsiveness in adults with asthma

Ozone exposure aggravates asthma, as has been demonstrated in both controll ed exposures and epidemiologic studies, In the current double-blind crossov er study, the authors evaluated the effects of dietary antioxidants (i.e., 400 IU vitamin E/500 mg vitamin C) on ozone-induced bronchial hyperresponsi veness 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 di etary antioxidants responded less severely to su[fur 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 mo re pronounced when subjects were grouped by response to sulfur dioxide at t he screening visit. The results suggest that dietary supplementation with v itamins E and C benefits asthmatic adults who are exposed to air pollutants .