Babies who were breastfed for a longer period of time perform better on language and intelligence tests at ages three and seven, reveals a new study published by JAMA Pediatrics.

Earlier this year, researchers reported that compared to formula-fed children, those who were breastfed during their first three months of life were more cognitively and behaviourally advanced. The breastfed babies had a 20 to 30% larger growth in brain white matter.

Study design

This study involved over 1300 women and their babies. While pregnant, these women had enrolled in a 1999 to 2002 US research named ‘Project Viva’. The mothers reported whether and for how long they breastfed their children. The researchers also investigated the degree to which maternal fish consumption during lactation influences the link between infant feeding and later cognition.

Study findings

  • Language tests: After considering the mothers’ intelligence and other familial factors, the researchers found that for every additional month of breastfeeding, the children scored better on the tests. The Peabody Picture Vocabulary Test was performed when the children were 3.On the language test, children who were exclusively breastfed for six months scored three points higher on average compared to those who were never breastfed.
  • Intelligence tests: Each extra month of breastfeeding was again associated with an improved performance on the Kaufman Brief Intelligence Test which was carried out when the kids were 7.
  • Motor skills and memory: The duration of breastfeeding did not appear to influence the children’s memory aptitudes and motor skills.
  • Fish intake during lactation: The association between breastfeeding duration and the ‘Wide Range Assessment of Visual Motor Abilities’ performed when the children were 3, appeared to be stronger in children whose mothers consumed at least 2 servings of fish per week compared to those whose mothers’ weekly diet included less than that amount of fish. However, this finding was not statistically significant.

According to study lead author, Dr Mandy Belfort, it is unlikely that a parent or teacher would notice a difference of a few points on a child’s intelligence test. She told Reuters Health that “the importance is more on the level of the whole population or society.” Dr Belfort explained that “if every child scored a few points higher, for example, there would be fewer kids on the very low end of the spectrum needing extra help.”

The authors concluded that “these findings support national and international recommendations to promote exclusive breastfeeding through age 6 months and continuation of breastfeeding through at least age 1 year.”

Study’s strength

“The difficulties with any study are, what were the intellectual capacities of the parents, and did this make a difference?” Dr. Ruth Lawrence told Reuters Health. “They showed very clearly that when you controlled for all those parameters, breastfeeding still was associated with higher intellectual development.”

Dr Lawrence, who wasn’t involved in the study, is a breastfeeding researcher from the University of Rochester Medical Center in New York. She explained that breast milk components such as amino acids, cholesterol and omega-3s could all be crucial for foetal brain development.

What you can do about it

If possible, try to breastfeed for a minimum of six months; if you need to go back to work you can always express your breast milk and ask a caregiver to feed your child.

For support, please call the National Breastfeeding Helpline on 0300 100 0212. You can also browse through the NHS website for a list of tips and links to other breastfeeding websites.


    Belfort et al (2013) Infant feeding and childhood cognition at ages 3 and 7 Years: Effects of breastfeeding duration and exclusivity. JAMA Pediatr. 10.1001/jamapediatrics.2013.455.

    Deoni et al (2013). Breastfeeding and early white matter development: A cross sectional study. NeuroImage. 82C:77-86.