Extending breastfeeding time increased IQ scores, years of education, and income later in life, according to a population-based birth cohort study of nearly 3,500 people.
The prospective study included nearly 6,000 infants born in Pelotas, Brazil, in 1982. The researchers recorded information on breastfeeding in early childhood and followed up 30 years later with a Wechsler Adult Intelligence Scale IQ test. They also collected information on education and income. The final analysis included 3,493 people.
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Individuals who had received 12 months or more of breastfeeding had an average IQ score that was 3.8 points higher than those who had been breastfed for less than 1 month. Those with a year or more of breastfeeding also had 0.91 more years of education on average, and earned 341 Brazilian reals per month more than those with the shortest breastfeeding time.
“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,” Bernardo Lessa Horta, Ph.D., of the Federal University of Pelotas in Brazil and lead author of the study, said in a statement. “Our finding that predominant breastfeeding is positively related to IQ in adulthood also suggests that the amount of milk consumed plays a role.”
The study was funded by the Wellcome Trust, International development Research Center (Canada), CNPq, FAPERGS, and the Brazilian Ministry of Health.
Find the full study in the Lancet Global Health (2015;3:e199-205).