Breastfed babies are not only healthier, they achieve higher intelligence scores and earnings in adulthood, according to a study that tracked the development of 3,500 newborns over 30 years.
Critically, the socioeconomic status of mothers appeared to have little impact on the results according to a paper published today in the April issue of 'Lancet Global Health'.
The researchers say their study provides the first evidence that prolonged breastfeeding not only increases intelligence until at least the age of 30, but also has an impact by improving educational attainment and earning ability.
"The effect of breastfeeding on brain development and child intelligence is well established," lead author Bernardo Lessa Horta of the Federal University of Pelotas in Brazil said.
"Our study provides the first evidence that prolonged breastfeeding not only increases intelligence until at least the age of 30 years but also has an impact both at an individual and societal level by improving educational attainment and earning ability", Dr Horta said.
He added: "What is unique about this study is the fact that, in the population we studied, breastfeeding was not more common among highly educated, high-income women, but was evenly distributed by social class."
Information on breastfeeding was compared to IQ test results at the average age of 30 years, as well as the educational achievement and income of 3,493 participants.
An individual breastfed for at least a year as a baby gained a full four IQ points, had 0.9 years more schooling, and an income of 341 Brazilian Reals (€98) higher per month at the age of 30, compared to those breastfed for less than one month, the study found.
"The likely mechanism underlying the beneficial effects of breast milk on intelligence is the presence of long-chain saturated fatty acids (DHAs) found in breast milk, which are essential for brain development," said Dr Horta.
"Our finding that predominant breastfeeding is positively related to IQ in adulthood also suggests that the amount of milk consumed plays a role."
In a comment also carried by The Lancet, Erik Mortensen of the University of Copenhagen said the findings had important public health implications.
"However, these findings need to be corroborated by future studies designed to focus on long-term effects and important life outcomes associated with breastfeeding."
