Breastfeeding may “rewire” babies’ brains in ways that help them acquire language and eventually learn to read, according to a new study from the West Virginia University Rockefeller Neuroscience Institute.
“The more an infant was breastfed, the more connective strength there was in certain parts of the brain associated with language performance,” said Christopher Bauer, who led the study. Previously a doctoral student at RNI, Bauer is now a postdoctoral researcher at the University of Kentucky.
Sixteen children between the ages of 4 and 8 participated in the study. Bauer and his colleagues used MRI to produce detailed images of their brains.
They also collected information from the children’s parents about if—and for how long—they were breastfed as babies.
After controlling for several external factors—including annual household income, each mother’s education level and whether either parent smoked—the researchers found that later weaning correlated to more vigorous growth of white matter in the left hemisphere.
In most people, the brain’s left hemisphere specializes in language. We engage it when we learn a new word, remember an acquaintance’s name or make sense of what someone is saying. Odds are, you’re relying on it right now to read this sentence.
The researchers discovered that even babies who were breastfed for just a few months experienced significant changes in white matter growth.
“Any breastfeeding is awesome,” said researcher Hawley Montgomery-Downs, who also oversaw the study. A freelance health science editor and consultant, Montgomery-Downs is a former professor of psychology at WVU.
“I'll also note that these benefits aren't just for the baby,” she said. “Moms, families, employers and society all benefit from breastfeeding. That said, babies also benefit from having a mom who is healthy and not beating herself up as a failure if she can’t breastfeed exclusively for a year. So, I’m also a big fan of women doing their best, taking advantage of all helpful resources—like lactation consultants—and then giving themselves a break.”
But why does white matter, matter? It’s crucial to connectivity within the brain. Just as electrical wiring connects a light switch to a lightbulb, white matter makes it possible for one brain region to communicate with another.
“The brain is made up of neurons,” Bauer said. “The bodies of these neurons make up the brain’s gray matter. The neurons communicate with each other through axons, which are like the wiring of the brain. Those axons make up the brain’s white matter.”
In the study, babies breastfed for longer durations tended to become children with more white matter in two particular areas of the left hemisphere: the left longitudinal fasciculus and the left angular bundle.
“Both of these tracts are implicated in language performance,” Bauer said. “Disruption of the integrity of the left longitudinal fasciculus is associated with language deficit. The left angular bundle is associated with verbal episodic memory. That refers to being able to remember words, names, poems, song lyrics, sentences and letters from events that happened in the past.”
It’s no secret that being breastfed correlates to having higher verbal and language function. Scientists have known that for years. But Bauer’s research gives insight into how that correlation develops.
“People who don’t breastfeed shouldn’t be shamed for it, but at the same time, those who do breastfeed shouldn’t be shamed either,” said Julie Brefczynski-Lewis, a research assistant professor at RNI who worked with Bauer on the project. “There can be this shame and stigma attached to breastfeeding past 12 months. But those mothers are still doing something worthwhile. They’re doing something that benefits the baby’s brain. They shouldn’t have to apologize for that.”
Title: Breastfeeding duration is associated with regional, but not global, differences in white matter tracts
CONTACT: Marisa Sayre
WVU Rockefeller Neuroscience Institute
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