Extended breastfeeding may lead babies to higher IQ and income later in life
We’ve heard it many times already—“Breast is best.” The benefits of breastfeeding for a child, physically and intellectually, have been increasingly well-illustrated by a large body of research in recent years. Now one more study adds to it.
Breastfeeding has many short-term benefits, including protection from infectious disease and reduction in infant death. Now a new study suggests that extended breastfeeding is linked to an increase in intelligence and income.
Prior studies have shown breastfeeding’s positive effects on brain development, and longer breastfeeding specifically has been linked with improved cognitive, motor, and language skills, as well as better memory in the first few years of life. A 2013 study published in JAMA Pediatrics found longer breastfeeding was associated with improved verbal and non-verbal intelligence in elementary age children; breastfed children have an increase of up to 7.5 IQ points.
But does the benefit last to adulthood? The answer is “yes!” The latest addition to this perspective is a long-term study of infants born in Brazil in 1982. Published in Lancet Global Health, the provocative longitudinal study interview 5,914 new mother about their plans for breastfeeding and then followed up to see how they did. Researchers recently followed up with the grown children, who were asked to complete IQ tests and answer questions about income and educational achievements. The researchers were able to collect data from 3,493 participants.
The study subjects were then divided into five groups based on how long they were breastfed. They took into account 10 “social and biological variables” that might affect IQ. These included family income at birth, parental schooling, maternal smoking during pregnancy, maternal age, birthweight, and how the baby was delivered.
Controlling for other facts such as parental income and birthweight, researchers found that the connection between breastfeeding and IQ may persist for many more years than previously had been shown—in fact, it may last right up through adulthood. The researchers from the Federal University of Pelotas in Brazil found that the longer a child is breasted, the higher his or her IQ through age 30, and the higher his or her earning power at that time. Babies who were nursed for 12 months or longer had higher IQ scores and earned more than those who had just been breastfed for a month.
The study provides the first evidence that prolonged breastfeeding not only increases intelligence, but last until at least the age of 30 years.
“The result of our mediation analysis suggested that IQ was responsible for 72% of the effect on income,” said Dr. Bernardo Lessa Horta who lead the probe.
In comparisons of participants who were breastfed for 12 months or more with those breastfed for less than one month, the increase in monthly income was roughly R$300 (US$95), or 20% of the average income level.
The study said that weather a mother was rich or poor, or had high or low social status, made little difference to the results. Longer breastfeeding led to increased adult intelligence, longer schooling and higher adult earnings, regardless of family background.
Horta said, “What 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.”
Breast milk may be the best a mother can give her child, even better than a rich family or a higher social class. One more reason to breastfeed, moms.
TO-WEN TSENG 曾多聞