Babies with high numbers of bifidobacteria and low numbers
of Staphylococcus aureus may be protected from
excess weight gain, according to a team of researchers
from the University of Turku in Finland.
Their study was published in the March issue of The
Journal of Clinical Nutrition.
The researchers suggested their findings may help explain
why breast-fed babies are at lower risk for later obesity,
since bifidobacteria are prevalent in the guts of breast-fed
Other studies repeatedly have found that being breast-fed
is associated with a reduced risk of excess weight or
obesity in childhood, with the risk lowered from 13 percent
to 22 percent.
In the new study, researchers evaluated children who
had been part of a long-term study to evaluate the effect
of probiotics on allergic disease. Probiotics are potentially
beneficial bacteria found in foods such as yogurt and
in dietary supplements.
The children had been evaluated at birth, five more times
before age 2, and then again at ages 4 and 7. The researchers
in the original study had also tested for intestinal microbes
in fecal samples collected at 6 months and 12 months.
For this latest study, the Finnish researchers selected
49 participants from the larger study -- 25 of them were
overweight or obese at age 7 years, and 24 were normal
weight at the same age.
When they looked at the fecal samples, the average bacterial
counts of bifidobacteria when taken at 6 months and 12
months were twice as high in those who were a healthy
weight as in those who got heavy.
Those who stayed at a healthy weight also had lower fecal
S. aureus levels at 6 months and 12 months than
did those who got heavy.
The S. aureus may trigger low-grade inflammation,
the authors speculated, and that may also contribute to
In other research, gut bacteria in adults have been found
to be altered in obese adults who lost weight. Someday,
the Finnish researchers speculated, tinkering with gut
flora may help prevent or treat obesity.
The latest study doesn't pinpoint exactly why intestinal
bacteria are linked with the development of obesity, said
Connie Diekman, director of university nutrition at Washington
University in St. Louis and president of the American
"The exact role that bacteria in the intestine play
in development of obesity is still the subject of much
research," she said, "but the benefits of breast-feeding
are clear. Breast-feeding provides not only the proper
nutrition for your infant, but it provides benefits that
may impact long-term health and weight issues as well."
However, she added that, "while breast-feeding may
play a role in the weight of children, so many other factors
influence weight that parents shouldn't ignore good
role modeling of healthy
food choices, proper portions and regular physical
activity. Healthy weight is a combination of factors,
and no single issue will be the cause of weight gain or
the magic answer to weight loss."
Another expert who has studied how obesity changes microbes
in the gut calls the new study unique, because it collected
information over several years and could look for differences
in gut microflora. "The finding, that the lean children
harbored higher levels of bifidobacteria at younger ages,
is very intriguing," says Ruth Ley, a research assistant
professor at Washington
University School of Medicine in St.
Still, she says, research on the role of gut bacteria
in regulating body weight is in the very early stages.