Findings may explain why breast-fed infants less likely to be overweight later

FRIDAY, March 7 (HealthDay News) -- The mix of bacteria in a baby's gut may predict whether that infant will become overweight or obese later in life, a new study suggests.

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 American 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 babies.

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'/>"/>