PARIS, France — A toddler’s gut bacteria may reveal whether they’ll be overweight later in life by the age of five, a new study suggests. The gut microbiota, a complex community of microorganisms including bacteria, fungi, and viruses, develops and changes during the first few years of life. However, researchers say disruptions to its maturation process have been associated with health issues later in life, such as inflammatory bowel disease, Type 1 diabetes, and childhood obesity.
The research found a link between infants with a higher proportion of Firmicutes bacteria than Bacteroidetes bacteria in their gut and a higher likelihood of being overweight by the age of five.
“These gut bacteria influence weight because they regulate the amount of fat we absorb. Children with a higher ratio of Firmicutes to Bacteroidetes absorb more calories, increasing their potential for weight gain,” explains Gaël Toubon, a Ph.D. student at Inserm, the French National Institute of Health and Medical Research and the study’s author, in a media release.
The study aimed to establish the correlation between the gut microbiota composition of children at the age of three-and-a-half, their BMI at five years-old, and changes in their BMI between the ages of two and five. To analyze the predictive capacity of gut bacteria in determining future BMI, researchers utilized data from two French national studies, EPIPAGE2 and ELFE, encompassing premature and full-term infants, respectively.
At the age of three-and-a-half, stool samples were collected from each child. The researchers identified six specific types of gut bacteria as significant predictors of a five-year-old’s BMI.
Children with an increased presence of the Eubacterium hallii group, Fusicatenibacter, and the Eubacterium ventriosum group faced a higher risk of being overweight by age five. In contrast, higher numbers of Eggerthella, Colidextribacter, and Ruminococcaceae CAG-352 were associated with a lower BMI score at the same age. The research team discovered that predicted steroid hormone production and biotin levels, a B vitamin involved in numerous metabolic processes, were associated with a lower BMI at five years-old.
“The findings suggest that the key issue with the gut microbiota is not only the bacteria involved but also their functions,” Toubon explains. “The gut microbiota is proving to be a significant early-life factor capable of influencing weight gain during childhood and beyond. Our findings expose how an imbalance in specific bacterial groups may play a crucial role in obesity development. Additional research is needed to understand the precise bacterial species that influence risk and protection, and when the shift to obesity-favoring gut microbiota occurs. This could help determine the optimal timing for potential interventions.”
Furthermore, the researchers found that premature birth had no effect on subsequent BMI.
Study authors presented their findings at the European Congress on Obesity (ECO) in Dublin, Ireland.
South West News Service writer Alice Clifford contributed to this report.
