Breastfeeding and neurodevelopmental outcomes.
Breastfeeding has clear short-term benefits for child survival. Concerning its long-term consequences, it has been reported that subjects who had been breastfed would have a better performance in intelligence tests. In this review, we perused the recently published studies on the association of breastfeeding with developmental outcomes. A meta-analysis published in 2015 reported that intelligence quotient (IQ) was 3.44 points (95% confidence interval: 2.30; 4.58) higher among subjects who had been breastfed, and this association was observed even among those studies that controlled for maternal IQ. In the present review, we identified two studies that reported that duration of breastfeeding was positively associated with IQ in childhood, whereas another study reported that cognitive score at 67.9 years of age was higher among those subjects who had been breastfed for at least 6 months. Furthermore, two studies reported that the small gain in IQ was associated with higher school achievement and income in adulthood. Concerning the possible mechanisms for the effect of breastfeeding on development, children who had been breastfed showed greater gray matter volume in the left and right parietal and left temporal lobes and more activation in the right frontal and temporal lobes for perception tasks, whereas for the language task, the activation was higher in the left temporal lobe. Moreover, it has been reported that subcortical gray matter volume mediated the association between breastfeeding and IQ. The new studies identified in the review reinforce the evidence that breastfeeding has long-term consequences on performance in intelligence tests. In addition, this association between breastfeeding and development has long-term consequences on human capital, increasing earning ability.