Impact of nutritional supplements on cognitive development of children in developing countries: A meta-analysis

Patrick Ip,Frederick Ka Wing Ho,Kam Lun Hon,Mary Eming Young,Jin Sun,Winnie Tso,Chun Bong Chow,Nirmala Rao

doi:10.1038/s41598-017-11023-4

Abstract

Nutritional supplements may be important on cognition but the evidence is heterogeneous. This meta-analysis aimed (1) to determine whether nutritional supplements provided to pregnant women or young children could improve cognitive development of children in developing countries, and (2) to explore how supplementation characteristics could improve children’s cognitive outcomes. This meta-analysis examined nutritional supplementation studies in 9 electronic databases and 13 specialist websites. Experimental studies were included if they were published from 1992 to 2016, were conducted in developing countries, had nutritional supplementation for pregnant women or children aged ≤8, and reported effect sizes on cognitive outcomes. Interventions with confounded components, such as stimulation and parenting, were excluded. 67 interventions (48 studies) for 29814 children from 20 developing countries were evaluated. Childhood nutritional supplementation could improve children’s cognitive development (d 0.08, 95% CI 0.03–0.13) and those with ≥5 nutrients was particularly beneficial (0.15, 0.08–0.22). Antenatal supplementation did not improve cognitive development (0.02, -0.01 to 0.06) except for those implemented in the first trimester (0.15, 0.03–0.28). In conclusion, childhood nutritional supplementation was beneficial to cognitive development but could be optimised by providing multiple nutrients; antenatal supplementation should target pregnancy women in the first trimester for better cognitive benefits.

Highlights

Pregnant women and children under five are vulnerable to micronutrient deficiencies (MND)[1]
A recent meta-analysis has found a small but significant effect of nutritional supplements on child development[13] and another systematic review reported that the combination of stimulation and nutritional supplementation benefited development[14]
Another meta-analysis investigated the benefits of nutrition interventions on cognitive development of children under two; this identified a small effect for postnatal intervention but a null effect for antenatal intervention[15]

Summary

Introduction

Pregnant women and children under five are vulnerable to micronutrient deficiencies (MND)[1]. The first meta-analysis did not analyse how intervention characteristics (e.g. types and quantities of supplements) may affect the cognitive benefits, and the second review did not provide any quantitative synthesis of data. The current meta-analysis combined a new systematic literature search (for articles in 2013–2016) with the review commissioned by Department for International Development, UK (DFID, for articles in 1992–2012) with the following aims: (1) to examine to what extent did pure nutritional supplementation (i.e. the only difference between the intervention and control arms was nutritional supplementation, but not stimulation, parenting, or cash transfer, etc.) improve cognitive development of young children in developing countries, and (2) to examine the influence of supplementation characteristics (i.e. timing of intervention, types and quantity of nutrients, and duration of follow-up) on intervention benefits

Methods

Results

Conclusion