Could Breastfeeding Reduce Risk of Autism?

A lack of eye contact in babies has been linked to autism spectrum disorder (ASD), and now, a new study finds that breastfeeding could actually help.

Could Breastfeeding Reduce Risk of Autism? Luca Elvira/Shutterstock

You may have heard that avoiding eye contact is a sign of autism in infants, and many new moms anxiously await their newborn's gaze in order to rule out concern for it. It is true that lack of attention to others' eyes and the emotional info we get from them has been linked to autism spectrum disorder (ASD), a condition that affects social skills. Now, a new study published in the journal PNAS finds that breastfeeding could actually help babies at risk for ASD better perceive social cues from the eyes.

The eyes have it

As part of the research, scientists showed nearly 100 seven-month-olds pictures of happy eyes and angry eyes in order to test the babies' early social skills. "The ability to distinguish between emotional cues at an early age is crucial as the infant begins to experience the world," study author Kathleen Krol of the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany, tells Fit Pregnancy. "Happy eyes are a prosocial signal; they invite further contact, whereas angry eyes are a signal of threat." The study found that the longer the infants were exclusively breastfed, the more likely they were to gravitate toward happy eyes and avoid angry eyes, indicating better social development.

But when the researchers broke down the infants' genetic information, they discovered something interesting. "We found that exclusive breastfeeding impacted emotional eye preferences, but only in infants at risk for autism," Krol says. Why would breastfeeding have this effect? Previous research has shown that a specific gene variation is linked with autism and lower levels of oxytocin, the "feel good hormone" that breastfeeding releases. So, the study authors believe that the oxytocin from breastfeeding may increase the emotional IQ of infants who carry the gene variant. "Several adult studies have found that oxytocin administration increases the [effect] of positive social cues," Krol says. "We suggest that breastfeeding might have a similar influence in infants who produce less oxytocin of their own."

A chemical reaction

It's not known exactly how oxytocin passes to the baby during breastfeeding—the study notes that it occurs through the milk but also could be as a result of the close physical contact that happens when nursing. So mothers who are not nursing could help release oxytocin by skin-to-skin contact.

Although not much is known about the causes of autism, Krol says low levels of oxytocin could be a factor. "Research regarding autism and reduced oxytocin levels remains mixed and unclear," Krol says. "What we do know is that oxytocin levels seem to correlate with social functioning. Reduced oxytocin levels could be seen as a vulnerability factor for developing autism, but it is most likely not the only piece of this complex puzzle."

Although it may seem like the study is another reason for new moms to breastfeed, Krol says more research is needed before we can say that breastfeeding reduces autism. "We are currently following this cohort of infants in an effort to investigate this very question," she says. "It may be possible that the emotional biases [toward happy eyes] we've found in these infants will diminish, having little impact on the future behavior of the child. [But] if the emotional biases we've found persist into later childhood, I would hypothesize that breastfeeding exposure may reduce social impairments in those at risk for autism."

Because the decision of whether or not to breastfeed involves many factors, Krol is refraining from encouraging it based on her study. But, she says, "I do think it's important for the public to know that breastfeeding should not just be viewed as a means to feed an infant. It is a dynamic behavior, which is social in nature, and it has the ability to impact how infants perceive the world around them."