Effect of Ascorbic Acid on Aiway Hyperresponsiveness in Bronchial Asthma

Introduction : Ascorbic acid has been reported to have a role in the decrease of airway responsiveness in animal models. This data has been based on the regulation of airway tone and modulation of airway reactivity by ascorbic acid. Human studies show that ascorbic acid has a protective effect against the increase in bronchial responsiveness induced by ozone, and nitrogendioxide. We hypothesized that ascorbic acid may attenuate bronchial hyperresponsiveness in bronchial asthma.

 

Methods : We studied 15 mild asthma patients and 13 healthy non smoker controls. These patients were measured plasma ascorbic acid levels with 2,4-DNPH (dinitrophenyhydrazine) method and checked methacholine challenge with Chi method before and one hour after ascorbic acid intake (3gm). To assess chronic effect of ascorbic acid on airway responsiveness, these participants were checked again plasm ascorbic acid and methacholine challenge after daily intake of ascorbic acid (1gm) for 2 weeks.

 

Results : There were no significant differences in plasma ascorbic acid levels in asthma patients and controls. Bronchial hyperresponsiveness was decreased after ascorbic acid intake(3gm) in asthma patients, but not statistacally significant. This decrease was persisted with daily 1 gram of ascorbic acid intake for 2 weeks. PC20FEV1 were not correlated to plasma ascorbic acid levels in asthma patients.

 

Conclusion : In mild bronchial asthma, Airway hyperresponsiveness may be ameliorated by ascorbic acid supplementations. But further studies are necessary to address the question of the effectiveness of ascorbic acid in bronchial asthma