A study published in The Lancet Global Health, provides evidence that people who were breastfed as infants have a higher IQ, higher educational outcomes, and higher income, at age 30.
The study, conducted by researchers at the Universidade Católica de Pelotas, Pelotas, Rio Grande do Sul, Brazil, set out to determine if there was a link between infant breastfeeding, IQ, educational attainment, and income. The research began in 1982 across 5 maternity hospital in Brazil, where mothers and newborns were recruited to participate in the study. A total of 3 493 of the originally recruited infants were followed up in later life, between 2012 and 2013, when they were 30 years of age.
The participants were divided into two groups, the first being those who were never breastfed, (which also included those that were breastfed for less than one month), and the second group was made up of those who were breastfed for longer than one month.
The authors reported that the length of time the infants were breastfed was positively associated with IQ, educational achievement, and income, at 30 years of age. The longer the infants were breastfed, the greater the increase seen. They reported almost a 4 point difference in IQ between the infants who were breastfed for the shortest duration and infants who were breastfed for the longest duration.
The authors state that it is highly unlikely that socio-economic factors of the household the infant was born into had an effect on the outcomes. In Brazil during this time period, the rate of breastfeeding was not different between socioeconomic groups, instead it was evenly distributed across all groups. This means that the participants did not come from better-off, or highly educated homes.
The authors describe the potential reasons for the positive effect IQ as likely being due to components of breast milk that are beneficial for brain development, ultimately affecting intelligence. An example of this is long-chain fatty acids present in breast milk, such as DHA, which are necessary for brain development.
This report supports previous studies linking breastfeeding with IQ, however, it is the first to show a direct link between educational attainment and income. In this study the increase in income was approximately 20% of the average income, between those who were breastfed for less than one month and those who were breastfed for more than 12 months.
The authors suggest that the increase in IQ has a positive effect on society as a whole, ultimately resulting in an increase in educational achievement in addition to earning capability.
Victoria, CG, Horta, BL, de Mola, CL, Quevedo, L, Pinheiro, RT, Gigante, DP, Goncalves, H, Barros, FC. “Association between breastfeeding and intelligence, educational attainment, and income at 30 years of age: a prospective birth cohort study from Brazil” The Lancet Global Health, Volume 3, No. 4, e199-e205, April 2015.
Image courtesy of Serge Bertasius Photography at FreeDigitalPhotos.net
Written by Deborah Tallarigo, PhD