The Wall Street Journal recently reported that breast feeding your baby for a longer period of time can lead to greater intelligence, attributing the finding to a report published in the pediatric edition of the Journal of the American Medical Association (JAMA). Commenting on the JAMA Pediatric article, Medical Daily writes, “The researchers estimate a 0.8-point increase in verbal intelligence for every month a child is breastfed for up to one year.” But why? Why would breastfeeding lead to increased aptitude? And what do skeptics have to say about this?
In the past, skeptical researchers have pointed out that other, older studies linking breastfeeding to higher IQs in children have suffered from a wide variety of limitations—they were often small, didn’t account for the length of breast feeding and didn’t adjust for other factors that may have influenced intelligence. A 2012 Bloomberg report, for instance suggested that the mother’s IQ was the greater contributing factor and that smart mothers tend to breastfeed their infants.
However, the more recent, large-scale JAMA Pediatric study found that breast feeding does aid in a child’s intelligence. Perhaps the key to understanding this finding is to consider what it may be about breast milk that could possibly make it more beneficial for babies’ cognitive development than formula.
Dr. William Sears, a pediatrician for more than 30 years, has given us some clues about the intelligence benefits of breastfeeding. The biggest boost comes from the chemistry of breast milk. Babies’ brains are growing at an enormous rate compared with those of adults. Breast milk contains certain “smart” chemicals that are vital to healthy brain growth. According to Dimitri Christakis, a pediatrician at Seattle Children’s Hospital Research Institute, “There are nutrients in breast milk that don’t really exist anywhere else, and we don’t fully know why.”
One healthy substance contained in a mother’s milk is an omega-3 fatty acid known as DHA (docasahexaenoic acid). This vital nutrient is essential for brain tissue’s growth, development, and maintenance. A number of studies have found that children who consume higher amounts of omega-3 fatty acid have greater cognitive ability than their peers. While many brands of infant formula sold in the U.S. (including such long-established ones as Enfamil and Similac) now contain a DHA additive, it remains unclear whether this additive provides significant benefits.
Although “low cholesterol” is good for adults, the opposite is true for infants. They need the cholesterol to provide them with many of the necessary building blocks for creating nerve tissue in the growing brain. Mother’s milk is rich with cholesterol. You won’t find these “smart fats” in over-the-counter infant formula.
Mother’s milk is also rich in “smart sugar”— lactose. There’s more lactose in human milk than in cow’s milk, and this is a good thing for smart babies. When digested, lactose is broken down into galactose and glucose. And galactose provides more essential chemicals for healthy brain growth.
There is also some indication that the feeding experience itself may make a difference for infants. Babies may receive more or different stimulation from a mother while breastfeeding than from a mother who is feeding formula from a bottle. More stimulation causes faster growth in brain tissue.
So whether it’s the nutritional content of breast milk, the experience of nursing, or some combination of the two, the recent JAMA study suggests that children who breastfeed may in fact have a head start over those who don’t.