Babies who are breast-fed for at least one year grow up to be significantly more intelligent than those breast-fed for less than one month, according to a Brazilian study published in The Lancet Global Health.
Researchers at the Federal University of Pelotas followed nearly 6,000 people born in 1982 in Pelotas—a coastal city in southern Brazil–from birth until they were 30 years old.
When 3,500 of the subjects reached the age of 30, they were given intelligence tests and asked about their earnings. The subjects came from all social backgrounds, and the researchers controlled for a wide range of social and biological variables such as parental schooling, genomic ancestry, whether mothers smoked during pregnancy, mothers’ ages, birth weight and delivery type.
They found that across the board, breast-feeding came out as a major factor associated with increases in IQ, improved educational attainment and higher earning ability on average.
Major IQ Differences
Dr. Bernardo Lessa Horta said breast-feeding not only benefits babies, but also society as a whole as the children performed better on various metrics.
“Participants who were breastfed for 12 months or more had higher IQ scores (difference of 3·76 points), more years of education, and higher monthly incomes than did those who were breastfed for less than 1 month,” the investigators noted. Babies breast-fed for a year or longer earned about a third more than those breast-fed for less than one month. (Victoria CG, Horta B, et al. The Lancet Global Health. 2015: 3 (4): e199-e2052015).
Higher IQ is directly correlated with earning potential, as Dr. Horta pointed out: “The results of our mediation analysis suggested that IQ was responsible for 72 percent of the effect on income.”
What’s behind the results? Horta speculates that breast-feeding’s impact on intelligence might be due to the saturated fatty acids in breast milk that are necessary for brain development. He also suggests that the amount of breast milk an infant consumes may play a role in increasing his or her IQ.
A mother’s milk is both nutritious and medicinal, and is vital to a child’s physical, intellectual and emotional development. It helps prevent diseases and also brings mother and baby closer together emotionally. This bond releases oxytocin and opioids in response to an activation of the sensory nerve in the child’s brain that decreases stress response systems and provides feelings of wellbeing while also helping the brain develop (Uvnäs-Moberg K, et al. Front Psychol. 2014; 5: 1529).
The Brazilian study shows an association between breast-feeding and IQ, but not proof of cause and effect, according to Erik Mortensen of the department of public health at the University of Copenhagen in Denmark, who wrote an accompanying journal editorial. It is important not to overstate the case.
The Benefits of Nurturing
That said, the link is very strong, Dr. Mortensen admitted. “It may not be a causal effect, but in my judgment, the overall evidence from other studies and the Brazilian study suggests that the effects are causal.”
Mortensen added that it’s important for mothers to understand that breast-feeding does not determine their children’s destiny. “This study really points out the benefits of a nurturing environment, the energy and effort that parents put into.”
A large body of research over the decades has established the overwhelming list of benefits from breast-feeding—benefits that extend far beyond simple nutrition. As Dr. Horta’s study shows, the effect of Mama Nature’s tonic is both short-term and long-term, and its implications have a ripple effect on society as a whole.
Mothers who breast-feed are investing in not only their child’s future, but also in the wellbeing of their larger communities. So it’s imperative that we as health care practitioners provide a support system for moms trying to breast-feed, encouraging them and assuring them that their hard work and persistence will pay off tremendously.
So much research and money has been poured into creating formulas and medicines for children, but it seems we’ll never come close to beating what nature already gave us.