500-2000 mg vitamine C verlaagt mogelijk inspanningsastma

Research Question:
Vitamin C reduces the effort of swallowing-induced bronchoconstriction (exercise-induced asthma)?

Study Design:
This overview article contained 3 Rcts with 40 participants.
There was no heterogeneity (I2 = 0%) because the fixed effect model was used.
The dosage of vitamin C was 0.5-2 grams for 1 day or for several days. The average age in 1 study was 14 years and 25 and 26 years in other 2 studies.

Results and conclusions:
The researchers found that taking vitamin C just before the effort the chance of getting the effort-induced bronchoconstriction significantly reduced. The decrease in post effort FEV1 (forced expiratory volume in FEV1 = 1 sec) decreased significantly with 8.4% [95% CI = 4.6-12%, p 0.001].

The researcher concluded that people who suffer from effort-induced bronchoconstriction as possible helped in swallowing of 500-2000 mg of vitamin C just before the effort. Possible because there are too few studies were available and the studies also contain few participants.

Original title:
Vitamin C may alleviate exercise-induced bronchoconstriction: a meta-analysis by Hemilä H.


Additional information about El Mondo:
Read more about vitamin C.
It is not possible through feeding 500 mg of vitamin C to get inside.