The effects of micronutrient interventions on cognitive performance among school-aged children: A systematic review of RCTs

Background/Aims: Micronutrient interventions have been shown to benefit children's cognitive development, particularly in subjects who were micronutrient-deficient at baseline. However, the Results on healthy subjects remain inconsistent and effect on different cognitive domains remains equivocal. This systematic review highlights the effects of single and multiple micronutrient inventions on different cognitive domains among school-aged children from both developing and developed countries.
Methods: A systematic search of Medline, CINAHL Plus and Academic Search database was conducted to identify trials published after year 2000. Randomized controlled trials (RCTs) that evaluated the effect of micronutrient interventions on cognitive performance or academic performance among children aged 4-18 years were included. Data were extracted by 2 researchers. The cognitive outcomes assessed were grouped into seven cognitive domains for qualitative analysis.
Results: Nineteen RCTs were included for qualitative synthesis. The major cognitive domains assessed included fluid intelligence, crystallized intelligence, short-term memory, long-term memory, cognitive processing speed, attention and concentration, and school performance. Eight of ten trials reported significant improvement in the fluid intelligence domain among micronutrient-deficient children following micronutrient interventions, especially those who were iron-deficient or iodine-deficient at baseline. The effects of micronutrient interventions on other domains were inconsistent.
Conclusions: Improvement in fluid intelligence among micronutrient-deficient children was consistently reported. Further research is needed to provide more definitive evidence on the beneficial effects of micronutrient inventions on other cognitive domains and the effects in healthy subject from both developing and developed countries.