A review study published in The British Journal of Nutrition (2016) tried to update earlier evidence – published in 3 systematic reviews regarding the effects of prenatal and postnatal supplementation with iron, folic acid or n-3 long-chain PUFA (LCPUFA) on neurodevelopment of children – based on the recent data. The randomized controlled trials (RCTs) and meta-analyses in online databases such as MEDLINE and the Cochrane Database of Systematic Reviews were searched for this review study.
Iron plays an integral role in the human body, specifically for the development of the central nervous system. Iron deﬁciency anemia (IDA) can affect brain function and impede child development. A 2010 systematic review assessed the effects of iron supplementation on neurodevelopment of non-anaemic pregnant women and non-anaemic children. In an earlier meta-analysis, none of the ﬁve RCTsthat were reviewed addressing iron supplementation in infants showed a beneﬁcial effect of infant iron supplementation on the Mental Developmental Index (MDI) of the Bayley Scales of Infant Development, while three of the ﬁve RCTs showed a beneﬁcial effect on the Psychomotor Development Index (PDI) at some time points. In May 2014, this review was updated, and the database search showed one new follow-up study to a previously published RCT in which the authors had assessed the effects of daily iron and zinc supplementation on growth of children. The follow-up study assessed the impact of early supplementation of iron on mental and school performance of 9 years old children and found no signiﬁcant difference between the iron and placebo groups. According to the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (2014), there was no evidence of positive effects of iron supplementation of European pregnant women on their offspring, however, iron supplementation of low birth weight infants was recommended for the prevention of IDA.
Folic acid is required for brain development and function during pregnancy and early life and its deficiency is a risk factor for neural tube defects. A systematic review published in 2012 evaluated evidence regarding the impact of folic acid supplementation during pregnancy and early postnatal period on mental performance of children. Evidence from two RCTs did not find any positive effects of folic acid supplementation on mental development, the developmental quotient or the intelligence quotient of children. Hence, it was concluded that the folic acid supplementation during pregnancy was not beneﬁcial to the mental performance of children. The database search up to May 2014 did not identify any new RCTs regarding folic acid supplementation, however, some observational, prospective cohort and case–control studies showed a positive association between maternal folic acid supplementation and neurodevelopment of offspring at different stages. Overall, there is a consensus among various societies regarding the daily folic acid supplementation of 0.4 mg for all women of reproductive age for the prevention of neural tube defects.