Dose-response trial of prophylactic zinc supplements, with or without copper, in young Ecuadorian children at risk of zinc deficiency.
BACKGROUND
Multiple studies have shown the benefits of zinc supplementation among young children in high-risk populations. However, the optimal dose and safe upper level of zinc have not been determined.


OBJECTIVE
The objectives of this study were to measure the effects of different doses of supplemental zinc on the plasma zinc concentration, morbidity, and growth of young children; to detect any adverse effects of 10 mg supplemental Zn on markers of copper or iron status; and to determine whether any adverse effects are alleviated by providing copper with zinc.


METHODS
This randomized, double-masked, community-based intervention trial was conducted in 631 Ecuadorian children who were 12-30 mo old at baseline and who had initial length-for-age z scores <-1.3. Children received 1 of 5 daily supplements for 6 mo: 3, 7, or 10 mg Zn as zinc sulfate, 10 mg Zn + 0.5 mg Cu as copper sulfate, or placebo.


RESULTS
The change in plasma zinc concentration from baseline was positively related to the zinc dose (P < 0.001). Zinc supplementation, including doses as low as 3 mg/d, reduced the incidence of diarrhea by 21-42% (P < 0.01). There were no other significant group-wise differences.


CONCLUSIONS
Zinc supplementation with a dose as low as 3 mg/d increased plasma zinc concentrations and reduced diarrhea incidence in the study population. There were no observed adverse effects of 10 mg Zn/d on indicators of copper or iron status. The current tolerable upper level of zinc recommended by the Institute of Medicine should be reassessed for young children.
Wuehler
Sara E
SE
Department of Nutrition, Program in International and Community Nutrition, University of California, Davis, Davis, CA 95616, USA.
Sempértegui
Fernando
F
Brown
Kenneth H
KH
D002657:Child Development / Q000187:drug effects* / Q000502:physiology; D002675:Child, Preschool; D003300:Copper / Q000097:blood; D003967:Diarrhea / Q000453:epidemiology*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004484:Ecuador / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D007501:Iron / Q000097:blood; D008297:Male; D020714:Maximum Tolerated Dose; D009017:Morbidity; D015995:Prevalence; D014131:Trace Elements / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood; D016896:Treatment Outcome; D015032:Zinc / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood / Q000172:deficiency*
D014131:Trace Elements; D003300:Copper; D007501:Iron; D015032:Zinc