Does zinc with and without iron co-supplementation have effect on motor and mental development of children? A systematic review and meta-analysis

Abstract

Background Effects of zinc with and without iron co-supplementation on child development are uncertain therefore the aims of this systematic review were to explore whether supplementation with zinc alone and zinc with iron in children aged 0–5 years old have beneficial or adverse effects on their mental and motor development. Method We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, CINAHL, Web of Science and Scopus until July 2020 and included randomized controlled trials, which assessed effects of zinc supplementation with and without iron in children less than 5 years old on mental and motor development. Data were pooled by random effects model and the Standardized Mean Differences (SMDs) with 95% confidence interval were estimated. The heterogeneity was assessed by I2. Results Twenty-five studies with 11,559 participants were eligible to be included in this systematic review. Meta-analysis was conducted with eight articles that used Bayley Scales of Infant and Toddler Development II. We concluded that zinc alone and zinc with iron co-supplementation do not have beneficial or adverse effect on child mental and motor development at 6 and 12 months of age with low to moderate quality of the evidence. Furthermore, Zinc supplementation does not have any long term effect on child development in preschool and school age children. Conclusion Most included studies did not show the efficacy of zinc with and without iron co-supplementation on child mental and motor development up to 9 years old age. Further Randomized Controlled Trials (RCTs) need to be taken into considerations the context-based differences between countries with special focus on socio-economic differences.

Zinc Intakes and Health Outcomes: An Umbrella Review

“…Compared with no zinc intakes, the effect from lower supplementary zinc intakes could consistently be applied to other physical development parameters, including head circumference change ( 15 ), height-for-age z-scores (HAZ) change ( 15 ), MUAC ( 16 ), MUAC change ( 15 ), WAZ change ( 15 ), HAZ ( 15 , 16 ), weight for height z-scores ( 16 ) and psycho-motor development ( 39 ) as well as adulthood body fat percentage ( 40 ), body mass index (BMI) change ( 40 ), hip circumference ( 40 ), waist circumference change ( 40 ) and waist-to-hip ratio ( 40 ).…”

“…Apart from derivative diseases, we can also firmly believe that mental and motor development are strengthened by zinc supplementations. Yet from Tam's, Warthon-Medina's and Sajedi's studies, no statistically significant correlations were found between supplementary zinc intake (<20 mg/d) and mental development (MD: −0.15 point, 95% CI: −2.38, 2.09) ( 16 ), intelligence (SMD: 0.00 point, 95% CI: −0.12, 0.13) ( 7 ) and psycho-motor development (SMD: 0.30 point, 95% CI: −0.24, 0.83) ( 39 ), respectively.…”

The Role of Zinc and NMDA Receptors in Autism Spectrum Disorders

“…However, no control group was included in that study. In agreement with a lack of zinc deficiency in ASDs, a meta-analysis including 25 studies and over 11,000 participants found a lack of efficacy of zinc supplementation on child mental and motor development up to nine years of age [ 372 ].…”

Assessing the Correlation between Blood Trace Element Concentrations, Picky Eating Habits, and Intelligence Quotient in School-Aged Children

“…Furthermore, no study offered information regarding cognitive scores, Intelligence Quotients (IQs), or any potential side effects of zinc supplementation. Thus, there is no substantial proof to suggest that providing zinc supplements to infants or children leads to enhanced motor skills or cognitive development [59].…”