NEW YORK (Reuters Health) - School-age boys who were breastfed for at least the first six months of life may outperform their peers in reading, writing and arithmetic, a new study suggests.
The research, which followed more than 1,000 Australian children, found that 10-year-old boys who had been predominantly breastfed until at least the age of 6 months did somewhat better on a set of academic tests.
Compared with boys who’d been breastfed for less time, they scored an average of 10 percent higher in math and writing, 8 percent higher in spelling and 6 percent higher in reading.
No clear advantage was seen among breastfed girls, however.
The findings, reported in the journal Pediatrics, do not prove that breastfeeding itself boosted boys’ academic achievement. Indeed, the most important predictor of the boys’ performance was how much time parents spent reading with the child from an early age.
Nonetheless, even after accounting for such factors that could explain the link — including family income and mothers’ education levels — the association between breastfeeding and boys’ test performance remained.
The researchers say the results bolster what experts already recommend on breastfeeding.
“We know that breast milk, if the mother has a good diet, is the optimum and ‘best’ way of feeding a newborn baby — boys and girls — until at least 6 months and beyond,” said lead researcher Wendy H. Oddy, of the Telethon Institute for Child Health Research in Perth, Australia.
In an e-mail, she noted that the World Health Organization and the American Academy of Pediatrics already recommend that mothers breastfeed exclusively for the first six months, and then continue giving breast milk along with solid foods for the first year or beyond.
“These recommendations are in place because there is so much evidence to show the benefits of breast milk and breastfeeding,” Oddy said.
Breastfeeding is believed to lower infants’ risk of diarrhea, ear infections and sudden infant death syndrome (SIDS), and possibly to have longer term health benefits as well. Some studies have found that breastfed babies go on to have lower rates of asthma, obesity and diabetes, for example.
Breast milk also contains essential fatty acids involved in brain development, Oddy noted.
In line with that, some studies have linked breastfeeding to higher childhood IQ and better school performance. But not all have found that link, and questions remain about whether the advantage comes from breast milk, per se.
For their study, Oddy and her colleagues began following mothers during pregnancy, then assessed their children periodically through the age of 10. They were able to collect information such as how often parents read to their kids, to try to account for other factors that could explain any link between breastfeeding and academic prowess.
With those influences taken into account, longer term breastfeeding was still linked to better test scores in math, reading, writing and spelling in boys. Not so in girls, however.
According to Oddy, it is plausible that breastfeeding could affect academic performance differently in boys and girls.
There is evidence that boys are more vulnerable to “adversity” during critical periods of brain development than girls are. It’s possible, Oddy explained, that the estrogens in breast milk, thought to have a protective effect on brain cells, benefit boys more than they do girls.
Another theory is that boys might gain more from the mother-child bonding that comes with breastfeeding.
“A number of studies have found that male babies are more dependent on maternal attention to help develop their cognitive and language skills,” Oddy said.
Still, even if breastfeeding was responsible for the higher test scores in boys, the effects were modest.
And women who cannot breastfeed for prolonged periods should be reassured that there are many ways to aid their children’s development, Telethon Institute director Fiona Stanley said in a news release.
Noting that the strongest predictor of kids’ test scores was the amount of time their parents had spent reading with them at the ages of 3 and 5, Stanley said, “This highlights the important role of a nurturing environment in child learning.”
SOURCE: link.reuters.com/fyq23r Pediatrics, online December 20, 2010.