Breastfeeding and Child Cognitive Development

Abstract

Among the most consistently reported benefits of breastfeeding in developed country settings have been higher results on IQ tests and other measures of cognitive development among children and adults who had been breastfed compared with those who were formula-fed. A meta-analysis by Anderson et al¹ in 1999 reported consistent IQ differences favoring breastfed over formula-fed infants, with most differences in the 2- to 5-point range. Most of the studies included in the meta-analysis were observational in design and were carried out in subjects who were born healthy and at term, although a larger difference of 8 points was reported by Lucas et al² in follow-up of a randomized trial in preterm infants. Several of these studies demonstrated a clear dose-response relationship, with larger differences associated with longer durations of breastfeeding. With 1 recent notable exception,³ studies published since the meta-analysis have been entirely consistent with these results and conclusions.^4-9