Background: The effects of breastfeeding on neurodevelopmental outcomes are unclear. Inconsistent findings have been reported and confounding factors make interpretation of studies difficult. The World Health Organization published a systematic review on breastfeeding and intelligence in 2013, demonstrating a positive association with improved performance on intelligence tests. The objective of this review is to explore published literature since 2013 to examine the association between breastfeeding, cognition, executive function, and behavior. Methods: Duplicate searches were carried out using Web of Science and OVID for publications between January 2012 and March 2022. Non-English articles and those not correcting for maternal IQ or home environment were excluded. Results: Twenty-three studies were included, examining the effects of breastfeeding on cognition (21), executive function (3), and behavior (6). Most studies showed a modest dose-dependent increase in cognitive scores in children who were breastfed, test score differences ranging from 0.19 to 0.96 points per month of breastfeeding comparing any breastfeeding, predominant and exclusive breastfeeding. Four out of six studies showed a positive correlation between breastfeeding and behavior. One out of three studies assessing breastfeeding and executive function showed a positive dose-dependent correlation. Discussion: Recent evidence demonstrates that breastfeeding has a small positive effect on IQ in later childhood. Evidence suggesting that breastfeeding is a protective factor in developing conduct disorders and achieving higher executive function is limited. Further research is required. Limitations include potential confounders and recall bias of breastfeeding.
Keywords: IQ; behavior; breastfed; breastfeeding; cognition; executive function.