Effect of supplemental zinc on the growth and serum zinc concentrations of prepubertal children: a meta-analysis of randomized controlled trials.
BACKGROUND
Multiple studies have been carried out to assess the effect of zinc supplementation on children's growth. The results of these studies are inconsistent, and the factors responsible for these varied outcomes are unknown.


OBJECTIVE
Meta-analyses of randomized controlled intervention trials were therefore completed to assess the effect of zinc supplementation on the physical growth and serum zinc concentrations of prepubertal children.


METHODS
A total of 33 acceptable studies with appropriate data were identified by MEDLINE (National Library of Medicine, Bethesda, MD) searches and other methods. Weighted mean effect sizes (expressed in SD units) were calculated for changes in height, weight, weight-for-height, and serum zinc concentration by using random-effects models; factors associated with effect sizes were explored by meta-regression techniques.


RESULTS
Zinc supplementation produced highly significant, positive responses in height and weight increments, with effect sizes of 0.350 (95% CI: 0.189, 0.511) and 0.309 (0.178, 0.439), respectively. There was no significant effect of zinc on weight-for-height indexes [weighted mean effect size: -0.018 (-0.132, 0.097)]. Zinc supplementation caused a large increase in the children's serum zinc concentrations, with an effect size of 0.820 (0.499, 1.14). Growth responses were greater in children with low initial weight-for-age z scores and in those aged >6 mo with low initial height-for-age z scores.


CONCLUSIONS
Interventions to improve children's zinc nutriture should be considered in populations at risk of zinc deficiency, especially where there are elevated rates of underweight or stunting. The population mean serum zinc concentration is a useful indicator of the successful delivery and absorption of zinc supplements in children.
Brown
Kenneth H
KH
Program in International Nutrition and the Department of Nutrition, University of California, Davis 95616, USA. khbrown@ucdavis.edu
Peerson
Janet M
JM
Rivera
Juan
J
Allen
Lindsay H
LH
D000293:Adolescent; D000367:Age Factors; D001827:Body Height / Q000187:drug effects / Q000502:physiology; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D019587:Dietary Supplements; D005260:Female; D006128:Growth / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016239:MEDLINE; D008297:Male; D016032:Randomized Controlled Trials as Topic; D018401:Sample Size; D016896:Treatment Outcome; D015032:Zinc / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology*
D015032:Zinc