Prevention of exercise-induced asthma by a natural isomer mixture of beta-carotene

Ann Allergy Asthma Immunol. 1999 Jun;82(6):549-53. doi: 10.1016/S1081-1206(10)63165-1.


Background: The unicellular alga Dunaliella bardawil was previously shown to contain very high concentrations of beta-carotene composed of equal amounts of the all-trans and 9-cis stereoisomers which differ in their physicochemical features and antioxidative activity. Due to the controversy regarding the beneficial effect of antioxidants on asthma, the acute effects of beta-carotene of Dunaliella was assessed on airway hyperreactivity in patients with exercise-induced asthma (EIA).

Methods: Thirty-eight patients with EIA participated in our study to verify the antioxidative effect. The test was based on the following sequence: baseline pulmonary function, 7 minutes exercise session on a motorized treadmill, 8 minutes rest, 1-week oral random, double-blind supplementation of placebo or 64 mg/day beta-carotene, pulmonary functions at rest, 7 minutes exercise session, 8 minutes rest and again pulmonary functions.

Results: All patients given placebo showed a significant postexercise reduction of more than 15% in their forced expiratory volume in one second (FEV1). Of the 38 patients who received a daily dose of 64 mg of beta-carotene for 1 week, 20 (53%) were protected against EIA.

Conclusions: Our results indicate that a daily dose of Dunaliella beta-carotene exerts a protective effect against EIA in some patients most probably through in vivo antioxidative effect.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Administration, Oral
  • Adolescent
  • Adult
  • Antioxidants / therapeutic use*
  • Asthma, Exercise-Induced / prevention & control*
  • Child
  • Double-Blind Method
  • Female
  • Forced Expiratory Volume
  • Humans
  • Male
  • Placebos
  • Respiratory Function Tests
  • Stereoisomerism
  • Time Factors
  • beta Carotene / administration & dosage
  • beta Carotene / therapeutic use*


  • Antioxidants
  • Placebos
  • beta Carotene