17 Jun Vitamin C may alleviate exercise-induced Bronchoconstriction

MedicalResearch.com: Interview with: Dr. Harri Hemila

Department of Public Health,
University of Helsinki, Helsinki, Finland

MedicalResearch.com: What are the main findings of the study?

HH: Vitamin C administration may halve the exercise-induced FEV1 decline in people who suffer from exercise-induced bronchoconstriction.

MedicalResearch.com Were any of the findings unexpected?

HH: The benefit of vitamin C was not quite unexpected, but the level of consistency between the studies and the strength of the evidence were unexpected.

MedicalResearch.com What should clinicians and patients take away from your report?

HH: Vitamin C is inexpensive and it is safe even in high doses. Therefore, if a person has respiratory symptoms such as cough associated with exercise, I would encourage a pragmatic approach to test taking about 1 g of vitamin C some 1 to 2 hours before the exercise session.  If that helps, the person can regularly take vitamin C before exercise.

MedicalResearch.com What recommendations do you have for future research as a result of this study?

HH:  For example: First, what is the dose-dependency: the lowest dose of vitamin C was 0.5 grams and the highest was 2 grams, so is 0.5 grams sufficient or might larger doses be more effective?  Second, how does the benefit of vitamin C depend on the severity of exercise-induced bronchoconstriction: although the studies are consistent with the estimate that vitamin C halves the FEV1 decline, the studies are small and it is possible that the relation is not linear when a larger number of people are studied.

Citation: 

Vitamin C may alleviate exercise-induced bronchoconstriction

Hemila H. Vitamin C may alleviate exercise-induced bronchoconstriction: a meta-analysis. BMJ Open, 2013;3:e002416 DOI: 10.1136/bmjopen-2012-002416

Last Updated on September 19, 2013 by Marie Benz MD FAAD