Antioxidant Supplementation and Lung Functions among Children with Asthma Exposed to High Levels of Air Pollutants

Abstract

To evaluate whether acute effects of ozone, nitrogen dioxide, and particulates with mass median diameter less than 10 micro m could be attenuated by antioxidant vitamin supplementation, we conducted a randomized trial using a double-blinded design. Children with asthma (n = 158) who were residents of Mexico City were randomly given a daily supplement of vitamins (50 mg/day of vitamin E and 250 mg/day of vitamin C) or a placebo and were followed from October 1998 to April 2000. Pulmonary function tests were carried out twice a week in the morning. During the follow-up observation period, the mean 1-hour maximum ozone level was 102 ppb (SD = 47), and the mean 24-hour average PM(10) level was 56.7 micro g/m(3) (SD = 27.4). In children with moderate and severe asthma, ozone levels 1 day before spirometry were inversely associated significantly with forced expiratory flow (FEF(25-75)) (-13.32 ml/second/10 ppb; p = 0.000), FEV(1) (-4.59 ml/10 ppb; p = 0.036), and peak expiratory flow (PEF) (-15.01 ml/second/10 ppb; p = 0.04) in the placebo group after adjusting for potential confounding factors. No association between ozone and lung functions was observed in the supplement group. We observed significant differences in lung function decrements between groups for FEF(25-75) and PEF. Our results suggest that supplementation with antioxidants might modulate the impact of ozone exposure on the small airways of children with moderate to severe asthma.

Air pollution, oxidative stress and dietary supplementation: a review

“…Shortterm randomised supplementation trials suggest that antioxidant vitamins and n-3 polyunsaturated fatty acids might protect against the acute effect of these pollutants, particularly in vulnerable subgroups [80,96,106]. However, the evidence is still limited because of the small sample size in most studies and the lack of comprehensive assessment of baseline nutritional status and oxidative stress response.…”

“…In these studies, healthy adults were randomised to receive vitamin C (650 mg), vitamin E (75 mg) and b-carotene (15 mg) for several weeks [80,[93][94][95]. More recently, a study of asthmatic children exposed to high levels of air pollutants in Mexico City also suggested that supplementation with vitamin C (250 mg?day -1 ) and vitamin E (50 mg?day -1 ) had a modulating effect on acute lung function changes [96]. The positive effect of antioxidant supplementation was mostly found in children genetically susceptible to the effects of oxidants (glutathione S-transferases (GST)M1 null genotypes) [97].…”

“…Antioxidant vitamin supplementation provides some protection against the adverse effect of O 3 on lung function in asthmatic children with slight deficiencies in these nutrients [96], and to adults depleted in vitamin C [91]. In contrast, vitamin supplementation did not protect against O 3 -induced lung function decrement in well nourished subjects [109].…”

Lack of association between genetic variation in G-protein-coupled receptor for asthma susceptibility and childhood asthma and atopy

“…The residence of each child who participated in this study was located using a map and the closest monitoring station was assigned to that residence. 26 The ozone exposure data were collected for the year prior to the time of entry into the study. The parameter we used was the annual average of the daily maximum 8 h averages.…”

Polarographic Methods for Determination of Ascorbic Acid in Pharmacetical Preparations

“…Additional research is discovering that vitamin C can be helpful in preventing asthma [1]. Protecting against cancer, [2] and supporting healthy blood sugar levels in diabetics [3].…”