Does breastfeeding build better brains?

For some infants, being breastfed means a higher IQ later in life. But for others, breastfeeding doesn’t boost IQ score at all. A small difference in one gene, it turns out, makes all the difference. The gene, FADS2, helps turn the fatty acids found in breast milk into compounds important to brain development.

A team of researchers including Julia Kim-Cohen, Ph.D., assistant professor of psychology at Yale, discovered that children who have one version of FADS2 and who were breastfed scored 7 points higher on IQ tests administered up to age 13 than those who carry the same gene variant but drank formula milk. But for children who don’t have the special version of the gene, there was no IQ difference associated with being fed breast milk versus formula, the scientists report in the November 20 issue of Proceedings of the National Academy of Sciences.

“Previous research linking breastfeeding to IQ has been somewhat inconsistent. This gene may help explain that inconsistency,” says Kim-Cohen, who is now studying whether FADS2 and other genes play a role not only in cognitive development but in the emotional development of children.