New research in Switzerland reveals that vitamin C consumption can reduce the risk of developing bronchoconstriction caused by exercise.
Since vitamin C was first isolated in the 1930s, it has been proposed for the treatment of respiratory illnesses.
Dr. Harri Hemila reported his findings in the journal BMJ Open.
After doing exercise the airways can sometimes severely narrow and cause symptoms, such as:
- Shortness of breath
Previously known as exercise-induced asthma, exercise-induced bronchoconstriction results in a decline of more than 10% in forced expiratory volume in 1 second, caused by exercise.
Close to 1 in 10 people suffer from exercise-induced bronchoconstriction, it affects nearly half of all competitive winter sports athletes.
Vitamin C has been found to reduce the risk of common cold among people dealing with a lot of physical stress. This indicated that it could also be beneficial to people undergoing a lot of physical exertion too.
The new study looked at the effects that vitamin C intake had on bronchoconstriction caused by exercise, using data gathered from three relevant randomized placebo-controlled trials.
All of the trials revealed that vitamin C reduced FEV1 decline by over 50 percent following an exercise challenge test.
Dr. Hemilia said that given that the three trials resulted in positive outcomes, people should consider testing vitamin C on an individual basis to see whether it helps with any respiratory problems associated with exercise, such as cough or wheezing.
In fact, a review of placebo-controlled trials on Vitamin C and the common cold concluded that vitamin C could help people under heavy physical stress – such as marathon runners and skiers – reduce their risk of catching a cold.
29 trials involving 11,306 participants that compared vitamin C with placebo revealed that vitamin C intake had no effect on common cold incidence in the general population.
However, the trials that proved vitamin C’s ability to reduce the risk of catching the common cold were those conducted among people under short-term physical stress and marathon runners.
The authors of that study said that “the failure of vitamin C supplementation to reduce the incidence of colds in the general population indicates that routine vitamin C supplementation is not justified, yet vitamin C may be useful for people exposed to brief periods of severe physical exercise.”
Written by Joseph Nordqvist