Randomized trial of the effect of zinc supplementation on the mental health of school-age children in Guatemala

Background Rates of mental illness in children are increasing throughout the world Observational studies of depression anxiety and attention-deficit hyperactivity disorder suggest that zinc is an alternative treatment Objective We examined the effect of zinc supplementation on the mental health of school-age children in Guatemala Design From January to October 2006 we conducted a 6 mo randomized double blind controlled trial comparing zinc supplementation non (10 mg ZnO/d for 5 d/wk) with a placebo (10 mg glucose) in 674 Guatemalan children in grades 1-4 Outcome measures included intern timing (ie depression and anxiety) and externalizing (ie hyper activity and conduct disorder) problem behaviors positive behaviors (le socialization and leadership) and serum zinc concentrations Results Zinc and placebo groups did not differ significantly in any behavioral measures at baseline or at follow up At baseline 21 4% of children had serum zinc concentrations <65 mu g/dL At follow-up both groups improved significantly and zinc concentrations were higher in the zinc group Increases in serum zinc concentrations were inversely associated with decreases in depressive symp toms (estimate -0 01 points per mu g Zn/dL P = 0 01) anxiety (estimate -0 012 points per mu g Zn/dL P = 0 02) internalizing symptoms (estimate -0 021 points per mu g Zn/dL P = 0 02) rind social skills (estimate -0019 points per mu g Zn/dL P = 0 01) in adjusted models that weft controlled for child age sex, socioeconomic status household and treatment group Conclusions Six months of zinc supplementation did not induce differences in mental health outcomes between zinc and placebo groups However, increases in serum zinc concentrations were associated with decreases in internalizing symptoms (ie depression and anxiety) in a community based sample of children at risk of zinc deficiency This trial was registered at clinicaltrials gov as NCT00283660 Am J Clin Nutr 2010 92 1241-50