Children who were breast-fed exclusively for the first
three months of life or longer scored nearly six points
higher on IQ tests at the age of 6 than children who weren't
breast-fed exclusively, a new study has found.
The finding buttresses previous research that has suggested
that children and adults who were breast-fed as infants
scored better on IQ tests and other measures of cognitive
development, such as thinking, learning and memory, the
study authors said.
"Long and exclusive breast-feeding
makes kids smarter," said lead researcher Dr. Michael
S. Kramer, of McGill
University and the Montreal
Children's Hospital, in Canada.
Why breast-feeding might increase cognitive skills isn't
clear, Kramer said. "It could be something in the
milk, or it could be the physical contact between the
mother and the baby," he said. "It could be
the way the mother interacts with the baby during breast-feeding
-- there is no way to know."
The one thing Kraemer is sure of is that it has nothing
to do with differences between mothers. The women in the
new study were all from the eastern European country of
The findings are published in the May issue of the Archives
of General Psychiatry.
For the study, Kramer's group randomly assigned 7,108
infants in Belarus to exclusive breast-feeding; another
6,781 infants received the usual practice of breast-feeding
plus other foods.
When the children were 6.5 years old they were given
a standard IQ test. Those children who were exclusively
breast-fed scored, on average, 7.5 points higher in verbal
intelligence, 2.9 points higher in nonverbal intelligence,
and 5.9 points higher in overall intelligence.
In addition, their teachers said the breast-fed children
had significantly better academic performance in both
reading and writing, compared with children who weren't
Kramer thinks women should breast-feed exclusively for
at least three, and if they can, six months, and try to
continue breast-feeding for at least a year.
"For women in developed countries who can achieve
exclusive breast-feeding for at least three months, their
kids would benefit by about three or four IQ points,"
One expert thinks it's the nutrients in mothers'
milk -- which aren't found in other foods -- that
are essential for brain development and increased IQ.
"I'm not surprised because many studies have
had similar results," said Dr.
Ruth Lawrence, a professor of pediatrics
at the University
of Rochester School of Medicine, and a member of
the American Academy of Pediatrics executive committee
section on breast-feeding. "It's wonderful to
have this very large study to confirm what we've known
or thought for a long time."
Lawrence thinks that because mothers' milk contains
certain amino acids not found in formula, it's better
for infants' developing brains. These amino acids
three fatty acids and DHA (Docosahexaenoic acid),
which are important for brain growth, she noted.
Human milk also contains cholesterol, while formula doesn't,
Lawrence said. "We learned to fear cholesterol and
yet cholesterol is very important for brain tissue, it's
very important for nerve tissue," she said. "That's
why human milk is a better nutrient to support brain growth."
Many professional organizations, including the American
Academy of Pediatrics, recommend breast-feeding
as the best way to improve infants' overall health
and build their immune system. Breast-fed infants have
fewer hospital admissions, ear
infections, diarrhea, rashes, allergies and other
medical problems than bottle-fed babies, according to
Food and Drug Administration.