Breastfeeding is best and for many excellent reasons. Aside from the amount of money you get to save (no need to buy milk!), breastfeeding allows moms to create a unique bond with their child. It also helps makes postpartum recovery faster. (Read more about how breastfeeding is good for mom's health here.). Most importantly, breast milk contains all your baby's nutritional needs for the first six months of his life. The antibodies you pass on to your baby through breast milk also protects him from getting sick.
So the idea that breast milk can help with a child's cognitive development — his intelligence — was not hard to believe. A 2010 study claimed that by age 10, children who were breastfed for more than six months displayed better cognitive and language skills. A 2015 study published in The Lancet "traced nearly 3,500 babies, from all walks of life, and found those who had been breastfed for longer went on to score higher on IQ tests as adults," the BBC News reported, leading to higher educational attainment, better jobs, and higher income.
Three years after that research, the findings of a new study now suggest that breastfeeding have no impact on a child's overall neurocognitive performance by the time he reaches 16 years old.
“If you want to breastfeed in hope of increasing cognitive functioning scores, you may find some benefits in the early years,” said the lead author, Seungmi Yang, an assistant professor of epidemiology at McGill University in Montreal. “But the effect is going to be reduced substantially at adolescence. Other factors, such as birth order and parental education, are more influential.”
A follow-up to the Promotion of Breastfeeding Intervention Trial (PROBIT), this latest research was published in the journal PLOS Medicine and described by The New York Times as "a more rigorous type of study that better controls for socioeconomic and family variables."
Newborns were randomly assigned to either two programs: one was a program designed to promote exclusive and extended breastfeeding, and the other was a program that provided the usual postnatal care.
In the PROBIT study, the researchers checked the moms and babies' breastfeeding practices six times during the first year. When the babies were 6 and a half years old, they found that those assigned to the breastfeeding promotion group had higher intelligence quotient scores.
For the follow-up study, the researchers checked in on the kids, now age 16, who "took tests measuring verbal and nonverbal memory, word recognition, executive function, visual-spatial orientation, information processing speed and fine motor skills," reports The New York Times.
Results of the tests found no significant difference in IQ between the kids who were breastfed and those who were not although those who were breastfed "had slightly higher scores in verbal function."
A 2017 study published in the Pediatrics, the journal of the American Academy of Pediatrics (AAP), also found no significant association between breastfeeding and the baby's intelligence. (It showed that socioeconomic factors are a barrier to successful nursing.) Another study published in the same journal last year also found that infants who are breastfed do not have better cognitive skills by kindergarten than those who were fed formula.
These studies do not diminish in any way the health and lifesaving benefits of breastfeeding and breast milk. What it strongly suggests is a child's intelligence will not be determined solely by breastfeeding alone.
A lot of other factors help shape a child’s mind growing up, such as genes, socio-economic status, which includes the mother’s education, and how a parent nurtures her child's brain power and more importantly, his life skills.