Ascorbic acid supplementation attenuates exercise-induced bronchoconstriction in patients with asthma

Respir Med. 2007 Aug;101(8):1770-8. doi: 10.1016/j.rmed.2007.02.014. Epub 2007 Apr 5.


Background: Previous research has shown that diet can modify the bronchoconstrictor response to exercise in asthmatic subjects.

Objective: Determine the effect of ascorbic acid supplementation on pulmonary function and several urinary markers of airway inflammation in asthmatic subjects with exercise-induced bronchoconstriction (EIB).

Methods: Eight asthmatic subjects with documented EIB participated in a randomized, placebo controlled double-blind crossover trial. Subjects entered the study on their usual diet and were placed on either 2 weeks of ascorbic acid supplementation (1500 mg/day) or placebo, followed by a 1-week washout period, before crossing over to the alternative diet. Pre- and post-exercise pulmonary function, asthma symptom scores, fraction of exhaled nitric oxide (FENO), and urinary leukotriene (LT) C4-E4 and 9alpha, 11beta-prostagladin (PG) F2] were assessed at the beginning of the trial (usual diet) and at the end of each treatment period.

Results: The ascorbic acid diet significantly reduced (p < 0.05) the maximum fall in post-exercise FEV1 (-6.4 +/- 2.4%) compared to usual (-14.3 +/- 1.6%) and placebo diet (-12.9 +/- 2.4%). Asthma symptoms scores significantly improved (p<0.05) on the ascorbic acid diet compared to the placebo and usual diet. Post-exercise FENO, LTC4-E4 and 9alpha, 11beta-PGF2 concentration was significantly lower (p<0.05) on the ascorbic acid diet compared to the placebo and usual diet.

Conclusion: Ascorbic acid supplementation provides a protective effect against exercise-induced airway narrowing in asthmatic subjects.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-Asthmatic Agents / administration & dosage*
  • Ascorbic Acid / administration & dosage*
  • Asthma / prevention & control*
  • Asthma, Exercise-Induced / diet therapy
  • Bronchoconstriction / drug effects*
  • Cross-Over Studies
  • Dietary Supplements*
  • Double-Blind Method
  • Exercise Test / adverse effects
  • Female
  • Humans
  • Male
  • Respiratory Function Tests


  • Anti-Asthmatic Agents
  • Ascorbic Acid