1107 GMT August 18, 2019
Scientists at Penn State University found the composition of microorganisms in the mouths of two-year-olds offers clues to the child's future weight, UPI wrote.
The study's senior author, Kateryna Makova, a biology professor, said, "One in three children in the United States is overweight or obese.
"If we can find early indicators of obesity in young children, we can help parents and physicians take preventive measures," Makova said in a university news release.
More than 200 children took part in a project that analyzed the biological and social risk factors for obesity.
The researchers honed in on the digestive tract, home to a wide range of microscopic organisms that help the body digest food and boost the immune system.
They noted that previous studies have linked oral bacteria to obesity in adults and teens. For this study, the researchers investigated this association among children.
The study showed the children who had rapid weight gain as infants, which is a strong risk factor for childhood obesity, had fewer groups of bacteria or less diversity in their mouth bacteria. These children also had a higher ratio of Firmicutes to Bacteroidetes, two of the most common bacteria groups of the human microbiota.
The study's first author, Sarah Craig, a postdoctoral scholar in biology, said, "A healthy person usually has a lot of different bacteria within their gut microbiota.
"This high diversity helps protect against inflammation or harmful bacteria. ... There's also a certain balance of these two common bacteria groups, Firmicutes and Bacteroidetes, that tends to work best under normal healthy conditions, and disruptions to that balance could lead to dysregulation in digestion."
The study authors did not identify a link between weight gain and this reduced diversity or high Firmicutes to Bacteroidetes ratio. But they noted the gut microorganisms of toddlers may still be developing.
The study also showed that weight gain among young children was linked to the diversity of mouth bacteria in their mothers, suggesting a genetic or environmental influence.
"It could be a simple explanation like a shared diet or genetics, but it might also be related to obesity," Makova said. "We don't know for sure yet."