Moms, if you want your baby to grow up smarter and wealthier, you might want to consider prolonging breastfeeding until your child is at least a year old, according to a new study from Brazil. Published in The Lancet Global Health, the study found that longer duration breastfeeding is associated with increased intelligence, more schooling and higher earnings in adulthood.
“The effect of breastfeeding on brain development and child intelligence is well established, but whether these effects persist into adulthood is less clear,” Bernardo Lessa Horta, PhD, of the Federal University of Pelotas in Brazil, said in news release.
“Our study provides the first evidence that prolonged breastfeeding not only increases intelligence until at least the age of 30, but also has an impact both at an individual and societal level by improving educational attainment and earning ability,” added Horta.
Horta and his colleagues analyzed data from a study involving nearly 6,000 infants born in Pelotas, Brazil in 1982. After an average of 30 years, the researchers were able to measure IQs and gather educational and financial information from 3,943 participants.
Those in the study were divided into five groups based on the length of time they were breastfed. In addition, the investigators controlled for 10 social and biological variables that might affect an increase in IQ, including family income at birth, parental schooling, ancestry, birth weight, type of delivery, mother’s age and if she smoked while pregnant.
What differentiates this study from other studies on breastfeeding and its link to increased IQ is that it is not exclusive to more affluent and better educated mothers. “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,” Horta told Medical News Today.
While the study revealed increased intelligence, longer schooling and higher adult earnings at all duration levels of breastfeeding, babies who were breastfed longer derived the most benefits. Compared to infants who were breastfed less that one month, those who were breastfed for 12 months or longer gained four more IQ points, had 0.9 additional years of schooling, and earned an average of $104 per month more at the age of 30.
Horta suspects there is a biological reason for the study’s findings. “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,” he explained in the news release. He also speculated the amount of milk consumed plays a role.
The study authors acknowledged their research could not rule out the possibility other factors influenced their results.
“I don’t want to terrify people who did not breastfeed or who breastfed for a short time,” Horta told the New York Times. “It isn’t only breastfeeding that affects IQ and income. But our study does show that breastfeeding is important and should be encouraged.”