Gut bacteria differs in obese youth

Obese children and teens have different bacteria living in their digestive tracts than their leaner peers, according to a Yale-led study.
Feet of young girl in pink socks standing on a bathroom scale.


Obese children and teens have different bacteria living in their digestive tracts than their leaner peers, according to a Yale-led study. The findings could help researchers develop strategies to target specific gut microbes with the goal of preventing or treating obesity in youth, said the researchers.

The study was published Sept. 20 in the Journal of Clinical Endocrinology & Metabolism.

The rate of childhood obesity has increased in recent decades, and it affects 17% of children and teens nationwide. Research has revealed a link between obesity and differences in gut bacteria of adults. Yet little is known about the role of these microbes in childhood obesity.

In the study, a team lead by Nicola Santoro, M.D., examined gut bacteria and weight in 84 children and teens ranging in size from severely obese to normal weight. The researchers also measured body fat distribution, took blood samples, and asked participants to keep food diaries.

The research team identified eight groups of gut bacteria that were associated with the amount of fat in the body. These microbial groups were more common in obese children and teens compared to their normal-weight peers. These microbes were also more efficient at digesting carbohydrates, said the researchers, which in turn could lead to an increased production of fats.

Our findings show children and teenagers with obesity have a different composition of gut flora than lean youth,” said Santoro, an associate research scientist in Pediatrics. “This suggests that targeted modifications to the specific species composing the human microbiota could be developed and could help to prevent or treat early-onset obesity in the future.”

In addition, obese youth were more likely to have higher levels of short chain fatty acids, a type of fat produced by some gut bacteria, and probably linked with the production of fat in the liver.

Our research suggests that short chain fatty acids may be converted to fat within the liver and then accumulate in the fat tissue,” Santoro said. “This association could signal that children with certain gut bacteria face a long-term risk of developing obesity.”

Other authors of the study include Martina Goffredo, Kendra Mass, Emily Ann McClure, Joerg Graf, Elizabeth J. Parks, David A. Wagner, Mary Savoye, Bridget Pierpont, and Gary Cline.

The research was funded by the American Heart Association, the Yale Center for Clinical Investigation, the Allen Foundation Inc., and the National Institutes of Health’s National Center for Advancing Translational Sciences.


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