By Peter Modica
[Medical Tribune: Obstetrician & Gynecologist Edition 5(1): 1998.
© 1998 Jobson Healthcare
Breast-feeding a child for at least eight months may help improve cognitive
academic performance later in life, according to New Zealand researchers.
In a study of more than 1,000 teens, those who were breast-fed the longest
as infants scored
highest on standardized tests and I.Q. exams, L. John Horwood, M.Sc., B.A., and David M.
Fergusson, Ph.D., of the Christchurch School of Medicine in Christchurch, New Zealand,
reported in the Pediatrics electronic pages, the on-line version of the journal Pediatrics
These teens also rated higher on various other school evaluations than
those who were not
breast-fed or were breast-fed for less than eight months, they added.
Current guidelines from the American Academy of Pediatrics (AAP) in
Elk Grove Village, Ill.,
urge that newborns be nursed for at least one full year, noting that breast milk is "uniquely
superior" for infant feeding (see story, page 1).
Dr. Fergusson and Horwood speculated that long chain polyunsaturated
fatty acid levels and
particularly levels of docosahexaenoic acid (DHA) found in human breast milk are important for
healthy neurodevelopment during infancy and may explain why the breast-fed children had
better cognitive functioning.
The study was based on children born in New Zealand in 1977. Evaluations
were conducted at
birth, 4 months, one year, annually from ages 8 to 16, and again at age 18.
Though mothers in the study who breast-fed tended to be from a higher
and better educated--factors that might explain the higher test scores among their children--the
researchers still found a "small but detectable increase in childhood cognitive ability and
educational achievement" when these factors were considered.
Children who were breast-fed for at least eight months had test scores
that were, on average,
between 0.35 and 0.59 standard deviations units higher than children who were bottle-fed,
according to the report.
"[The] effects of breastfeeding are pervasive and reflected in a range
of measures including
standardized tests, teacher ratings and success in high school examinations," the team wrote.
The effects also were "relatively long-lived, extending throughout childhood into young
"These findings underscore the need to encourage breastfeeding," they wrote.
Judy Hopkinson, Ph.D., a lactation physiologist at the Children's Nutrition
Research Center at
the Baylor College of Medicine in Houston, agreed, noting that human breast milk is superior to
"Many reports indicate that breast-fed infants have some cognitive advantage
infants," she said. "None of these studies has shown advantages to formula feeding with
Currently, less than 60 percent of U.S. mothers breast-feed their newborns
in the first days of
life, and less than 22 percent nurse their infants at six months, according to the AAP.
"At the present time, it is important for families to think about following
the guidelines," Dr.
Hopkinson said. To assume that the benefits of human milk can be substituted in a synthetic
form is "probably a mistake," she added.