Breastfed babies have higher IQs

What the research found

A 2015 systematic review and meta-analysis of 17 studies found breastfed people scored 3.44 IQ points higher on average. In studies that accounted for the mother's IQ, the gap shrank to 2.62 points. The authors said a randomised trial also showed a benefit and suggested the link may be causal.

A 2023 systematic review looked at 23 studies published since 2013 that adjusted for maternal IQ or home environment. Most found a modest increase in thinking scores the longer a child was breastfed, about 0.19 to 0.96 points per month. Results for behaviour and executive function (skills like planning and self-control) were less consistent.

A 2016 Lancet meta-analysis also found breastfeeding was linked to higher intelligence. A 2024 review of preterm babies found those who were breastfed had better long-term cognitive scores than those who never were. Most of that evidence came from cohort studies, with only one trial.

What it doesn’t mean

• The difference is small on average and says little about any one child. Many things shape a child's thinking skills, including the home environment, and studies can't fully separate these from breastfeeding.
• This does not mean formula-fed babies will have lower IQs or that parents who can't breastfeed have done something wrong. Australian guidance says infant formula is the safest alternative when breastfeeding isn't possible.
• If you have trouble breastfeeding or worry about feeding or development, talk to your GP or child health nurse.