Effect of zinc supplementation in children with asthma: a randomized, placebo-controlled trial in northern Islamic Republic of Iran

Abstract

There are conflicting reports about the benefits of zinc supplements in childhood asthma. This study examined the effect of zinc supplementation in children with asthma attending an outpatient clinic in Sari, Islamic Republic of Iran. In a randomized, double-blind, placebo-controlled clinical trial over 8 weeks, 284 children on inhaled steroids were allocated to receive zinc supplements (50 mg/day) (n = 144) or placebo (n = 140). Cases and controls had low initial serum zinc concentrations [61.8 (SD 7.3) µg/dL and 60.9 (SD 4.3) µg/dL]. After treatment, mean serum zinc level in the case group was significantly higher [129 (SD 20.4) µg/dL] than in the controls [63 (SD 8.6) µg/dL]. There were no significant differences in IgE levels before and after treatment. The case group showed significant improvements in clinical symptoms such as cough, wheezing and dyspnoea and in all spirometry parameters (FVC, FEV1 and FEV1/FVC).

Zinc Supplementation in Children with Asthma Exacerbation

“…20 The present study used zinc supplementation on a daily basis but given in lower dosage (30 mg of zinc/day) compared to Ghaffari study. 19 However, we found relatively the same effectiveness in improving clinical symptoms of asthma as in the previous study. The dosage of zinc in this study was approximately 3-4 times of the recommended daily allowances as used for treatment of zinc deficiency.…”

“…18 Ghaffari and colleagues found that the 50 mg zinc supplement in children with asthma attending at outpatient clinic yielded significant improvements in clinical symptoms such as cough, wheezing, dyspnea and pulmonary functions during follow-up. 19 However, Pouramjad and colleagues reported the conflicting results that zinc supplementation by dosage of 50 mg on alternate days did not have any significant beneficial effect on pulmonary function parameters. 20 The present study used zinc supplementation on a daily basis but given in lower dosage (30 mg of zinc/day) compared to Ghaffari study.…”

“…18,19,26 Morgan and colleagues reported benefits of zinc supplementation given prior to allergen exposure on decreased airway hyperresponsiveness and serum IgE levels in an animal model. 26 Bitagi and colleagues reported the benefit of zinc supplementation on pulmonary functions and sputum inflammatory markers in children with moderate persistent asthma.…”

Relationship Among Serum Zinc Levels and Severity as Well as Control of Childhood Asthma

“…In the randomized placebo-controlled study by Ghaffari et al on 284 pediatric asthma patients, it was reported that when zinc levels significantly increased, improvements were seen in clinical symptoms such as coughing, wheezing and respiratory distress, and clear recovery of the FVC and FEV1 ratios in the group of patients given 50mg/day of zinc for 8 weeks (20). As opposed to some studies (7), our results raise the question that serum zinc levels might not have a significant effect on bronchoconstriction which leads these patients to develop frequent attacks.…”

Evaluation of zinc as anti-asthma agent: a preclinical study on guinea pigs

“…[3][4][5] Daily supplementation of low dose of zinc was proven to be beneficial at least in terms of reduction in severity of clinical signs and symptoms of bronchial asthma in children. 6 Unlike zinc, the deficiency of magnesium in asthma patients was not found in a clinical study but has shown the weak but significant effects in treatment of acute asthma. 7,8 This perhaps indicates the restricted role of magnesium in the treatment of only severe acute exacerbations of asthma.…”