Oral Zinc Supplementation May Improve Cognitive Function in Schoolchildren

Abstract

Zinc is an important micronutrient for humans, and zinc deficiency among schoolchildren is deleterious to growth and development, immune competence, and cognitive function. However, the effect of zinc supplementation on cognitive function remains poorly understood. The purpose of our study was to evaluate the effect of oral zinc supplementation (5 mg Zn/day for 3 months) on the Full Scale Intelligence Quotient (FSIQ), Verbal Intelligence Quotient (VIQ), and Performance Intelligence Quotient (PIQ) using a Wechsler Intelligence Scale for Children (WISC-III). We studied 36 schoolchildren aged 6 to 9 years (7.8 ± 1.1) using a nonprobability sampling method. The baseline serum zinc concentrations increased significantly after zinc supplementation (p < 0.0001), with no difference between sexes. Tests were administered under basal conditions before and after zinc supplementation, and there was no difference in FSIQ according to gender or age. The results demonstrated that zinc improved the VIQ only in the Information Subtest (p = 0.009), although the supplementation effects were more significant in relation to the PIQ, as these scores improved for the Picture Completion, Picture Arrangement, Block Design, and Object Assembly Subtests (p = 0.0001, for all subtests). In conclusion, zinc supplementation improved specific cognitive abilities, thereby positively influencing the academic performance of schoolchildren, even those without marginal zinc deficiency.

Brazilian studies on zinc deficiency and supplementation: emphasis on children

“…The quality criteria in which articles presented the greatest limitation were, in particular, proof of representativeness of the sample studied in relation to the study population (in observational and experimental studies); definition of main confounding factors (in observational studies) and description of loss of participant (in observational and experimental studies). Considering that all the articles had an average or high quality and that the main risks of bias were associated with the analysis of loss of participants and confounding factors, without negative effects on the objectives of the review, we decided to systematize all the studies The analysis of sample representativeness indicates that 15 studies 16,17,19,20,29,31,34,36,[38][39][40]42,[44][45][46] used a representative sample and random selection of participants, five 15,18,21,22,37 studied a large population percentage and ten 23,24,26,27,30,32,33,35,41,43 studied populations with no characteristic of representativeness. With the exception of two studies, 25,30 representativeness was guaranteed in all others that focused on preschool children (Tables 1 and 2).…”

“…27 According to Table 2, the impact on growth, development and improvement of nutritional status of micronutrients was considered in five, 34,36,39,42,45 three, 31,32,44 and seven studies, 33,35,36,39,41,43,46 respectively, out of 16 experimental studies. [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] The hypothesized effect of zinc supplementation on growth was confirmed in children living in an urban area of Fortaleza, CE, 39 and in schoolchildren of short heigth in Rio de Janeiro. 42 The three studies 31,32,44 showed a positive effect on development, according to the indicators used by the researchers.…”

“…[31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] The hypothesized effect of zinc supplementation on growth was confirmed in children living in an urban area of Fortaleza, CE, 39 and in schoolchildren of short heigth in Rio de Janeiro. 42 The three studies 31,32,44 showed a positive effect on development, according to the indicators used by the researchers. The effect of zinc supplementation on the nutritional status of micronutrients was found in six 33,35,36,41,43,46 of the studies with suchlike analyses, of which five studies 33,35,36,41,43 reported the effect on zinc nutritional status.…”

Importance of zinc for the human body in the aspect of zinc supplementation

“…[52] wykazały, że podawanie dzieciom szkolnym preparatów zawierających cynk w dawce 5 mg na dzień wpływa pozytywnie na rozwój psychiczny i psychomotoryczny. Opierając się na skali słownej i bezsłownej testu inteligencji, skonstruowanego przez Davida Wechslera stwierdzono, że zwiększone stęże-nie cynku w organizmie rozwija zdolności dzieci do nauki, rozumienia, zauważania błędów, planowania, analizy wzrokowej, abstrakcyjnego rozwiązywania problemów oraz poprawia pamięć długotrwałą [52]. W grupie osób dorosłych suplementacja diety preparatami cynku przynosi korzyści w przebiegu wielu schorzeń.…”

Suplementos nutricionales en el desarrollo psicomotor y cognitivo en la infancia: Una revisión de la literatura

“…Black et al (12) realizaron un estudio en Estados Unidos en el que 221 niños con bajo peso al nacer recibieron suplemento con hierro (20mg/día), zinc (20mg/día), hierro más zinc y un compuesto con múltiples micronutrientes en el que se evidenció la superioridad de la suplementación combinada con hierro y zinc en beneficios para desarrollo psicomotor, con mejores resultados en los niños con lactancia materna superior a 6 meses. El estudio de Sungthong et al (20)the effect of intermittent iron supplementation on impaired cognitive function, one of the serious consequences of iron deficiency among children, has not been studied.…”