Vitamin C for asthma and exercise-induced bronchoconstriction.

Area of Science:

• Pulmonology
• Nutritional Science
• Clinical Trials

Background:

• Dietary antioxidants like vitamin C may reduce oxidative lung damage.
• Vitamin C may benefit inflammatory airway conditions such as asthma.
• Its role in asthma severity and exercise-induced bronchoconstriction requires further understanding.

Purpose of the Study:

• To evaluate vitamin C supplementation's impact on asthma exacerbations.
• To assess vitamin C's effect on health-related quality of life (HRQL) in asthma patients.
• To compare vitamin C supplementation against placebo or no intervention.

Main Methods:

• Systematic review of randomized controlled trials (RCTs) identified through the Cochrane Airways Group Register.
• Inclusion of trials involving adults and children with asthma or exercise-induced bronchoconstriction.
• Focus on daily vitamin C supplementation for preventing exacerbations and improving HRQL.

Main Results:

• 11 trials with 419 participants were included; most studies had inadequate design reporting and low-quality evidence.
• No significant difference in HRQL was found in adults with asthma; data on exacerbations were limited or unsuitable for analysis.
• Limited evidence suggests potential lung function improvements for exercise-induced bronchoconstriction, but studies were small and inconclusive.

Conclusions:

• Robust evidence for vitamin C's efficacy in asthma management is currently lacking.
• Further high-quality research is necessary to determine vitamin C's role in asthma and exercise-induced bronchoconstriction.
• Vitamin C is not currently recommended as a therapeutic agent for asthma.