Effects of prenatal and/or postnatal supplementation with iron, PUFA or folic acid on neurodevelopment: update

Abstract

Neurodevelopment has been linked, among other factors, to maternal and early infant diets. The objective of this review, which is part of the NUTRIMENTHE research project 'The effect of diet on the mental performance of children' (www.nutrimenthe.com), was to update current evidence on the effects of nutritional interventions such as iron, folic acid or n-3 long-chain polyunsaturated fatty acid (LCPUFA) supplementation during pregnancy and/or in early life on the mental performance and psychomotor development of children. In May 2014, we searched MEDLINE and The Cochrane Database of Systematic Reviews for relevant studies published since 2009. The limited updated evidence suggests that iron supplementation of infants may positively influence the psychomotor development of children, although it does not seem to alter their mental development or behaviour. The use of multivitamin-containing folic acid supplements during pregnancy did not benefit the mental performance of the offspring. Evidence from randomised controlled trials (RCT) did not show a clear and consistent benefit of n-3 LCPUFA supplementation during pregnancy and/or lactation on childhood cognitive and visual development. Caution is needed when interpreting current evidence, as many of the included trials had methodological limitations such as small sample sizes, high attrition rates, and no intention-to-treat analyses. Taken together, the evidence is still inconclusive. Large, high-quality RCT to assess the effects of supplementation with iron, LCPUFA or folic acid are still needed to further clarify the effects of these, and other nutrients, on neurodevelopment. Recent recommendations from scientific societies are briefly presented.

Perinatal nutrition impacts on the functional development of the visual tract in infants

“…Nevertheless, a sufficient supply of LC-PUFAs is likely to be of importance upon weaning from the breast milk 21 The published human studies provide contradictory data regarding maternal diet or fatty acid status during pregnancy on child development even though variable methods have been used to evaluate this phenomenon (reviewed in ref. 22 ). Generally, an increase in n-3 fatty acids either through consumption of relevant food sources, mainly fish or supplement use, has been considered as being beneficial in view of the importance of n-3 LC-PUFAs as structural and functional components in brain and retina 23 .…”

“…Nevertheless, despite intensive research in the area of fatty acid supplementation, no conclusive evidence exists thus far regarding child neurodevelopment or cognition and visual outcomes (reviewed in ref. 22,30 ), the benefits mainly manifested in preterm born infants 31 . In agreement with our study, although in that other publication, the child's development was evaluated by a psychological test, Mendez and co-workers 32 found that maternal fish consumption in excess of two to three times per week was associated with higher test scores when the child was four years old.…”

“…This is of importance as fetuses and infants have a limited capacity to synthesize n-3 LC-PUFA (reviewed in ref. 22 ). Maternal genetic variability may be a contributor to the maternal LC-PUFA status, but no evidence was revealed of its impact on the child's cognitive development as evaluated by Bayley Scales of Infant Development II test in a longitudinal observational study in high fish consumers at the age of 20-30 months 36 .…”

“…Another likely cause for differences in the study results may arise from the methods, particularly those used to evaluate neurodevelopment. Several studies have focused on the evaluation of perinatal diet on infantile mental performance and psychomotor development instead of neurodevelopment 22 , which was the focus in the present study using eye pVEP measurement known to be a robust test. Many previous studies investigating relationships between nutritional factors and neurodevelopment have exploited either electroretinography that reflects the function of the retinal cells, not the higher level central nervous system (CNS) maturation, or sweep-VEP giving a crude measure of visual acuity in babies (reviewed in ref.…”

The Influence of DHA on Language Development: A Review of Randomized Controlled Trials of DHA Supplementation in Pregnancy, the Neonatal Period, and Infancy

“…Although aspects of language are captured by various assessments in a many of these RCTs, these are often overlooked as secondary or exploratory outcomes, and hence there is yet to be a review where language outcomes are collated and considered as a whole [ 19 , 20 , 21 , 22 , 23 , 40 , 41 ]. Furthermore, whilst adequate DHA is likely to be important throughout the whole of the first 1000 days, two reviews to date have attempted to synthesize [ 42 ] or provide at least a very brief overview [ 43 ] of the evidence across this period and language was not reported in either.…”