Written by Greg Arnold, DC, CSCS. A review of 3 studies found that 40 subjects who took 500 – 2000 mg of vitamin C before exercising experienced a 50% reduction in exercise-induced bronchoconstriction.
Exercise-induced asthma, also called exercise-induced bronchoconstriction, is defined as having a greater than 10% decrease in the amount of air exhaled when exercising, called Forced Expiratory Volume. The current data suggests that exercise-induced bronchoconstriction is present in 10% of the general population, but in half of those in competitive athletics (1).
The cause of exercise-induced bronchoconstriction remains unknown, but inflammation is thought to be a contributing factor. Water loss during exercise leads to the release of inflammatory substances including histamine, leukotrienes and prostaglandins, all of which can cause bronchoconstriction (2). While exercise-induced bronchoconstriction is not a life-threatening condition, it can significantly decrease quality of life (3), placing a premium on the need to find a way to help with lung health during exercise. Now a new study (4) suggests vitamin C may be a safe, affordable option.
In the study review, researchers identified three studies consisting of 40 subjects with an average age of 14 (5), 25 (6), and 26 (7) taking vitamin C ranging in doses from 500 to 2,000 milligrams before completing a bout of exercise. The researchers found that vitamin C supplementation produced a 50% decrease in exercise-induced bronchoconstriction, evidenced by a 8.4-point improvement in the Forced Expiratory Volume (p < 0.001), with the greatest benefit seen at the highest dose of vitamin C, 2,000 milligrams per day, producing an 11.2-point improvement (p = 0.002) (5).
While the researchers conclude the “Given the low-cost and safety of vitamin C and the consistency of positive findings in the three studies on exercise-induced bronchoconstriction, it seems reasonable for physically fit and active people to test vitamin C on an individual basis”, the small sample size for this review also led them to suggest that “further research on the effects of vitamin C on exercise-induced bronchoconstriction is warranted.”
Source: Hemilä, Harri. “Vitamin C may alleviate exercise-induced bronchoconstriction: a meta-analysis.” BMJ open 3.6 (2013): e002416.
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Posted June 26, 2013.
Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY. You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com
References:
- Weiler JM, Anderson SD, Randolph C. Pathogenesis, prevalence, diagnosis, and management of exercise-induced bronchoconstriction. Ann Allergy Asthma Immunol 2010;105(6 Suppl):S1–47.
- Anderson SD, Kippelen P. Airway injury as a mechanism for exercise-induced bronchoconstriction in elite athletes. J Allergy Clin Immunol 2008;122:225–35.
- Kojima N. Exercise-induced asthma is associated with impaired quality of life among children with asthma in Japan. Allergol Int. 2009;58(2):187-92. doi: 10.2332/allergolint.08-OA-0034. Epub 2009 Feb 25.
- Hemela H. Vitamin C may alleviate exercise-induced bronchoconstriction: a meta-analysis. BMJ Open. 2013 Jun 20;3(6). doi:pii: e002416. 10.1136/bmjopen-2012-002416.
- Cohen HA, Neuman I, Nahum H. Blocking effect of vitamin C in exercise-induced asthma. Arch Pediatr Adolesc Med 1997;151:367–70.
- Schachter EN, Schlesinger A. The attenuation of exercise-induced bronchospasm by ascorbic acid. Ann Allergy 1982;49:146–51.
- Tecklenburg SL, Mickleborough TD, Fly AD, et al. Ascorbic acid supplementation attenuates exercise-induced bronchoconstriction in patients with asthma. Respir Med 2007;101:1770–8.
