Microbes weigh in on obesity

Overweight children host intestinal bacteria as babies that are different from those hosted by other kids, a new study finds. The results, which suggest that some gut microbes may protect against developing obesity, could lead to new approaches for managing unhealthy weight gain in childhood.

Infants receive their first dose of microbes from mom during birth, and that bacterial population is reinforced during breast-feeding. Bifidobacterium, a genus of branched, rod-shaped microbes, dominates the guts of healthy, breast-fed infants, and the bacteria’s presence has been linked to a well-functioning immune system. (Previous research had correlated breast-feeding with a reduced likelihood of childhood obesity, hinting at a more direct link between mom’s milk and weight development.)

A new study from the University of Turku in Finland of 25 overweight or obese 7-year-olds and 24 healthy 7-year-olds compared the intestinal microbes the children had hosted as infants (fecal samples were taken and analyzed when the kids were 6 and 12 months old, as part of a different study).

Bifidobacterium microbes were twice as abundant in the poop of infants who grew up to be kids of a healthy weight than of those who became overweight, the researchers report in the March American Journal of Clinical Nutrition. What’s more, the overweight kids had more Staphylococcus aureus in their guts as infants. Famous for its resistance to many antibiotics, staph has also been linked to chronic, low-grade inflammation, which has been linked to obesity.