Effect of ascorbic acid supplementation on pulmonary functions in healthy adults: a randomized controlled pilot study.

Abstract

The fact that oxidative stress plays an important role in the pathogenesis of various pulmonary diseases is supported by the beneficial effect of antioxidants. It is also well known that an altered oxidant-antioxidant balance after the age of 35 years increases the susceptibility to develop obstructive lung diseases later in life. Given this, the present study was designed to evaluate the effect of antioxidant supplementation on lung functions in healthy adults after the age of 35 years. Persons of age≥35 years (n=45) were randomized into three arms (each comprising 15 participants) to receive either no intervention (NI arm), ascorbic acid 250mg daily (AA250 arm), or ascorbic acid 500mg daily (AA500 arm) for 6weeks. Forced vital capacity (FVC), forced expiratory volume in 1s (FEV1), FEV1/FVC, and peak expiratory flow (PEF) were measured at baseline and 6weeks. Persons of age group (20-30 years) were also enrolled in the study to compare their lung functions and cardiovascular parameters at baseline with those≥35 years of age. All the adverse events experienced by participants were recorded. Baseline pulmonary functions were found to be comparable among the three study arms and compared to≥35 years age group, these parameters were found to be better in the younger age group (20-30 years). Most of the pulmonary functions were comparable among the three study arms at 6weeks. A significant improvement in PEF and % predicted PEF was noted in AA250 arm when compared to baseline values (p=0.049 and 0.026, respectively) and in participants with normal pulmonary functions when compared to those with reduced functions at baseline (p=0.059 and p=0.037). Although ascorbic acid did not affect most ofthe pulmonary functions in healthy adults, it improved PEF and % predicted PEF at a daily dose of 250mg. In this regard, it was found effective in individuals with normal pulmonary indices at baseline.