Effects of zinc supplementation on nutritional status and cognition in children

Background Zinc deficiency is common in children in develop- ing countries and data suggests the effects are detrimental towards children’s growth and neuropsychologic performance. Results of multiple studies which assess these effects have been inconsis- tent. Objective To evaluate the effects of zinc supplementation on nutritional status and cognition in children with zinc deficiency. Methods Forty-six stunted children aged 50-80 months with low hair zinc levels were randomly assigned to receive either 7.5 mg elemental Zn or placebo twice a week for 3 months. Anthropom- etry and cognition were assessed at the beginning and the end of the supplementation period. Differences among both groups for anthropometry and cognition before and after supplementation were analyzed with paired t-test. A comparison of different anthropom- etry and cognition among the two groups were analyzed using the independent t-test. Results There were no significant differences among baseline characteristics except on sex distribution.There was a significant difference in weight for age between the zinc group and placebo [0.28 (SB 0.18) vs 0.09 (SB 0.14); P=0.0001]. Height increments were also greater in the zinc group [0.34 (SB 0.15) vs 0.02 (SB 0.12); P=0.0001). There was no significant difference between weight for height. Intelligence quotient (IQ) measured by the Stanford-Binnet test was slightly higher in the zinc group [2.26 (SB 3.11) vs 2.00 (SB 2.81], but the difference was not significant ac- cording to sex. Conclusion Zinc supplementation produced highly positive re- sponses in weight for age and height for age increments in chil- dren with zinc deficiency compared with placebo. There was no effect of zinc supplementation on weight for height index and none on cognition measured by intelligence quotient (IQ