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A 14-mo zinc-supplementation trial in apparently healthy Chilean preschool children
M Ruz1, C Castillo-Duran, X Lara
1Department of Nutrition, Faculty of Medicine, University of Chile, Santiago. mruz@machi.med.uchile.cl
Insights
Zinc supplementation improved height gain in preschool boys from low socioeconomic backgrounds. This study highlights zinc
Area of Science:
- Pediatric Nutrition
- Human Growth and Development
- Micronutrient Research
Background:
- Preschool children in low socioeconomic settings often have inadequate zinc intake.
- Zinc deficiency can impair growth and immune function in children.
- Previous studies have not consistently shown zinc's impact on growth without specific inclusion criteria.
Purpose of the Study:
- To investigate the effect of zinc supplementation on the growth and health of apparently healthy preschool children from low socioeconomic backgrounds.
- To determine if zinc supplementation impacts anthropometric, clinical, biochemical, and functional indexes in this population.
- To assess sex-specific responses to zinc supplementation.
Main Methods:
- A 14-month double-blind, placebo-controlled trial involving 98 preschool children (aged 27-50 months) from low socioeconomic conditions in Santiago.
- Participants were pair-matched by sex and age, receiving either 10 mg of zinc per day or a placebo.
- Measurements included anthropometrics, clinical signs, dietary intake, biochemical markers, and functional tests at baseline, 6 months, and 14 months.
Main Results:
- Children in the zinc-supplemented group showed a trend towards greater height gain (0.5 cm) over 14 months (P = 0.10).
- Boys in the supplemented group exhibited significantly greater height gain (0.9 cm) compared to the placebo group (P = 0.045), while girls showed no significant difference.
- Trends suggested potential benefits in boys, including increased mid-arm muscle area, improved tuberculin response, and reduced parasite reinfestation rates in the supplemented group.
Conclusions:
- Zinc appears to be a limiting factor for growth potential in preschool children from low socioeconomic environments.
- Zinc supplementation may be particularly beneficial for improving growth outcomes in boys within this demographic.
- Further research could explore the broader health and functional impacts of zinc supplementation in vulnerable preschool populations.
Abstract:
Apparently healthy preschool children (46 boys, 52 girls) aged 27-50 mo from low socioeconomic conditions who attended daycare centers in Santiago participated in a 14-mo long double-blind zinc supplementation trial. Unlike most previous studies, no additional inclusion criteria such as short stature or slow growth rate were considered. Subjects were pair matched according to sex and age and randomly assigned to two experimental groups: the supplemented group, which received 10 mg Zn/d, and the placebo group. Selected anthropometric, clinical, dietary, biochemical, and functional indexes were determined at the beginning of the study and after 6 and 14 mo of intervention. Actual dietary zinc intake was 66% of the recommended dietary allowance. Height gain after 14 mo was on average 0.5 cm higher in the supplemented group (P = 0.10). The response, however, was different between sexes. Boys from the supplemented group gained 0.9 cm more than those in the placebo group (P = 0.045). No effect was seen in girls. Although no significant differences were observed in the rest of the variables studied, trends (0.05 < P < 0.10) in the supplemented group compared with the placebo group for increased midarm muscle area in boys, improved response to tuberculin, and reduced rates of parasite reinfestation were noted. We conclude that in preschool children of low socioeconomic status, zinc is a limiting factor in the expression of growth potential.
