Improved lung function following dietary antioxidant supplementation in exercise-induced asthmatics

•Supplementation of Ascorbic acid (vitamin C) and α-tocopherol (vitamin E) leads to improvements in pulmonary function at minute 5 and minute 15 in forced vital capacity (FVC); forced expiratory volume in 1-s (FEV1); peak expiratory flow rate (PEFR); and forced expiratory flow between 25 and 75% of vital capacity (FEF25–75%) and minute 30 in FEV1 and FEF25–75% post-exercise following three week of supplementation in EIA subjects.•Supplementation also may improve FVC in subjects without EIA 5 and 15 min post-exercise.•Considering dietary antioxidant supplementation appears to help patients with EIA, this might help them become less dependent on medications and provide them alternative treatments for EIA.

IntroductionOxidative stress is a characteristic of exercise-induced asthma (EIA), however antioxidant supplementation may attenuate EIA. The purpose of this study was to determine if ascorbic (AsA) and α-tocopherol supplementation would improve airway function in subjects with EIA.MethodsA single-blind randomized crossover design with eight clinically diagnosed EIA subjects (22.0 ± 0.7 year) and five healthy control subjects (28.2 ± 1.4 year) was used. Subjects consumed vitamins (V) (AsA 500 mg; α-tocopherol 300 IU) or placebo (PLA) daily for three weeks, followed by a three week washout period and then three weeks of the alternative treatment. Ten-minute treadmill tests (90% VO2peak) were performed with pulmonary function testing (forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and between 25 and 75% (FEF25–75%), and peak expiratory flow rates (PEFR)) measured pre-exercise and 1, 5, 15, and 30 min post-exercise.ResultsSupplementation led to significant improvements at minute 5 and minute 15 in FVC; FEV1; PERF; FEF25–75% and minute 30 in FEV1 and FEF25–75% post-exercise.ConclusionAsA and α-tocopherol may aid the recovery of pulmonary function in subjects with EIA.