Breast-feeding may help prevent obesity
2001-05-16 11:41
New York - Showing that the road to
obesity may begin with a person's first meal, new research
suggests that breast-feeding reduces the risk of becoming
overweight by the teen years.
In two studies looking at the effects of breast milk and
formula on weight later in life, investigators found that
breast-feeding significantly lowered the odds of being
overweight by the early teen years, but showed less effect on
weight during early childhood. Results from both studies are
published in the May 16th issue of The Journal of the American
Medical Association.
Although the two studies might seem contradictory, the
findings do make sense, according to Dr. William H. Dietz of
the Centres for Disease Control and Prevention in Atlanta,
Georgia.
"It's more of an apparent discrepancy than a real one," he
said in an interview with Reuters Health. For one, he noted,
animal research suggests that the effects of infant diet do not
become apparent until later in life. In addition, Dietz said,
the study of younger children was much smaller and, therefore,
less equipped to show significant effects.
In the larger study, Dr Matthew W. Gillman and his
colleagues at Harvard Medical School in Boston, Massachusetts,
looked at more than 15 300 adolescents aged 9 to 14. They found
that those who had been breast-fed were less likely to be
overweight compared with those who were raised mostly or
exclusively on formula. Kids fed mainly breast milk for the
first 6 months of life were 22% less likely to be overweight by
age 14.
And the longer the children were breast-fed, the lower the
odds of being overweight. For example, those who were
breast-fed for at least 7 months were 20% less likely to be
overweight than those given breast milk for 3 months.
The link between breast-feeding and weight remained even
after Gillman's team considered key factors like the children's
calorie intake, exercise levels and their mothers' body weight.
It is unclear exactly why breast-feeding might cut
children's risk of obesity later. One possibility is that
formula and breast milk have different impacts on babies'
metabolism, with breast milk having more positive effects on
fat storage. This ômetabolic programming," Gillman told Reuters
Health, may not manifest itself until later in life.
Indeed, the second study, by researchers at the National
Institutes of Health in Bethesda, Maryland, showed a weaker
link between breast-feeding and weight among children aged 3 to
5. Breast-fed children were much less likely than those never
given breast milk to be on the verge of becoming overweight.
But they were only 16% less likely to actually be overweight,
report Dr. Mary L. Hediger and her colleagues.
But, Dietz pointed out in the interview, this study was
much smaller - looking at less than 2 700 children - and that
could skew the results.
And if breast-feeding has even a modest positive effect on
weight, that should be hailed as good news, according to Dietz.
"We have relatively few strategies for obesity prevention,"
he said. Although breast-feeding "will by no means prevent all
cases of obesity," Dietz added, "it's a start."