"Among nearly 200,000
4-year-olds who had nursed for 12 months, [the children] were 28
percent less likely to be overweight, and children who had nursed
for three to six months lowered their risk by 19 percent," says
Sharon Donovan, nutritionist at the University of Illinois. The
statistics were from an article published in a recent issue of
Pediatrics, with authors from the Centers for Disease Control.
Donovan says that one of the
reasons why breast-feeding could prevent obesity is the timing of
the development of fat cells. "There are three critical times in
life when the body normally produces fat cells," says Donovan.
"Those times are prenatal, in the first year of life and during
adolescence. And, unfortunately, once you get fat cells, they're
with you for life." Donovan says that because the baby
self-regulates its breast milk intake and stops nursing when full,
breast-feeding may be one way for mothers to have some effect on the
number of fat cells their baby produces in that first year of life.
"It's almost impossible to
force a breast once a baby is satisfied and comes off," says
Donovan. "But when a baby is formula-fed, it's easier for the parent
to be concerned if there is a lot left in the bottle and to try to
encourage the baby to finish it."
Another major factor is the
consistency of breast milk versus formula. "Breast milk is more
watery at the beginning of a feeding, when the baby is hungriest,
and the fat content is higher toward the end of the feeding, which
contributes to the feeling of fullness," says Donovan. "Formula has
the same fat and calorie content for the entire bottle, so
formula-fed babies do not get that 'satiety signal' that helps to
trigger the end of the feeding."
Breast-feeding also appears to
be beneficial after solid foods are introduced into a baby's diet.
One study done at the University of California at Davis in
California found that when solids were introduced into a baby's diet
at 4 to 6 months of age, breast-fed babies took in less breast milk.
But when formula-fed babies began eating solid foods, they consumed
the same amount of formula. "Since the first solids introduced are
very low in fat -- rice, fruits and vegetables -- the primary fat
intake would come from the formula or breast milk," says Donovan.
[to top of second column
in this article]
Donovan cautions that babies
need fat in their diet. "We don't want to send a message to parents
to restrict fat intake. But very heavy babies do tend to continue to
be heavy throughout childhood." If breast-feeding can help reduce
the number of fat cells produced at that time of life, it could be
one way to give children a leaner start.
"When compared to growth charts
that pediatricians use to monitor infant growth, breast-fed babies
tend to gain weight rapidly at first and then drop off later in the
first year, so some physicians and parents may think that the
breast-fed baby isn't thriving." Donovan says that studies comparing
the health of breast-fed babies show that they are healthier than
formula-fed infants and that there is no adverse effect on
development associated with the slower weight gain during the second
six months of life.
"Since breast-feeding was the
norm during thousands of years of evolution," she says, "some
experts feel that the pattern of growth of breast-fed babies should
be the norm rather than growth charts that were established using
data from predominately formula-fed infants."
Cultural beliefs also play a
role in childhood obesity. "In some cultures, fat babies are healthy
babies," says Donovan. "Obesity may not carry the same stigma in
some minority populations."
Donovan and a graduate student, Pasasie Adedze, are working with
University of Illinois Extension and the Head Start program in
Chicago to develop culturally appropriate take-home materials that
will help families follow the guidelines for healthy eating and
exercise that their children learn in the Healthy Moves for Healthy
Children program at school.
[University of Illinois news release]