Do Breast Fed Babies Do Better?
Ability and Academic Achievement Enhanced?
In the debate over whether babies should be on the
breast or bottle, few points may prove as persuasive as the results
of a new study indicating that breastfeeding is associated with
detectable increases in child cognitive ability and educational
The study was reported in the January 1998 issue of the journal
Pediatrics that is published by the American Academy of Pediatrics.
The report is by L. John Horwood and David M. Fergusson from the
Christchurch School of Medicine in Christchurch, New Zealand.
The study looked at the relationships between the duration of breast
feeding --- how long children were on the breast -- and their
cognitive ability and academic achievement over a period of 8-18
years. The data were collected in the course of an 18-year
longitudinal study beginning at birth of over 1000 children.
From birth to a year of age, information was collected on maternal
breast feeding practices. Then, over the years the children were
tested on a range of measures of cognitive and academic performance.
These included "measures of child intelligence quotient; teacher
ratings of school performance; standardized tests of reading
comprehension, mathematics, and scholastic ability; pass rates in
school leaving examinations; and leaving school without
Longer breastfeeding was found to be associated with consistent and
statistically significant increases in:
- Intelligence quotient of the children tested at age 8-9
- Reading comprehension tested at age10-13 years
- Mathematical ability tested at age10-13 years
- Scholastic ability tested at age10-13 years
- Teacher ratings of reading and mathematics at 8-12 years and
- Higher levels of attainment in school final examinations.
There were differences between the mothers who breast fed and those
who bottle fed. The mothers who chose to breast feed as a group
tended to be older, to be better educated and from upper
socioeconomic status families. They tended to be in a two-parent
family, did not smoke during pregnancy and enjoyed above average
income and living standards. The rates of breast feeding also
increased with increasing birth weight.
To take these various factors into account, statistical regression
adjustments were made for maternal and other factors associated with
breast feeding. Nonetheless, the duration of breast feeding remained
a significant predictor of later cognitive or educational outcomes.
Breast feeding, it is concluded, is associated with small but
detectable increases in the cognitive ability and educational
achievement children. These effects are reflected in a range of
measures including standardized tests, teacher ratings, and academic
outcomes in high school. The beneficial effects of breast feeding in
the New Zealand study were long-lived and extended throughout
childhood into young adulthood.
The New Zealand study is not alone in suggesting that breast feeding
helps children's cognitive abilities and academic achievement.
Longitudinal studies have consistently shown that breast fed babies
do better in these respects than bottle-fed babies.
What makes the difference? Is it the experience of being on the
breast? Or is it the breast milk itself? Data from an experimental
study of pre-term (premature) babies show that children whose mothers
elect to express their own breast milk later have higher
developmental scores and higher intelligence quotients. Thus, the
breast milk itself appears beneficial.
What is in breast milk that is so good for the brain? Research has
suggested that the helpful factors may be long-chain polyunsaturated
fatty acids including, in particular, docosahexaenoic acid (DHA).
When DHA was added to infant formulas, pre-term babies appeared to
show better visual acuity and cognitive abilities.
The New Zealand investigators observe that their findings "underwrite
the need to encourage breast feeding and/or to continue to develop
improved infant formulas with properties more similar to those of
human milk...." They do believe that their results most
likely "reflect the effects of polyunsaturated fatty acid levels and,
particularly, DHA levels on early development.
The Nutrition Information Center of New York Hospital-Cornell Medical
Center and Memorial Sloan-Kettering Cancer Center recently advised
that DHA is "included in infant formulas worldwide, but not in the
U.S." (underlined in the advisory). Assuming DHA is required for
optimal brain development -- a reasonable conclusion at this time --
the question arises. Why are infant formulas in the United States
not supplemented with DHA?
Last Editorial Review: 4/11/2002