Previous studies have shown supplementation with ascorbic acid (vitamin C) improves lung function and reduces bronchoconstriction in individuals with exercise-induced asthma. Researchers at the Human Performance and Exercise Biochemistry Laboratory at Indiana University placed eight asthmatic subjects on 1500 mg/day of ascorbic acid or placebo for two weeks, then crossed the groups over to the other substance for another two weeks (after a one-week washout period). After supplementation with ascorbic acid there were significant improvements in asthma symptom scores and post-exercise lung function (FEV1) compared to baseline and placebo. Markers of inflammation and bronchconstriction were also improved on ascorbic acid therapy.
Tecklenberg SL, Mickleborough TD, Fly AD et al. Ascorbic acid supplementation attenuates exercise-induced bronchoconstriction in patients with asthma. Respir Med 2007;101:1770-1778.
