Summary: A new study finds that the composition of a child’s gut microbiota at two years old is linked to body mass index (BMI) at age 12. Researchers suggest that analyzing a toddler’s gut bacteria could help identify children at higher risk of developing obesity.
Source: ASM
Evaluating the infant gut microbiota during the first two years of life may help identify children at risk for becoming overweight or obese, according to a recent study published in mBio. The research shows that gut microbiota composition at age two is associated with BMI at 12 years, and that BMI at age two did not reliably predict later obesity. These findings indicate that the gut microbiome could serve as an early biomarker for obesity risk.
“Our results add evidence that the gut microbiota may play a role in later obesity,” said lead author Maggie Stanislawski, PhD, research associate at the LEAD Center, University of Colorado Anschutz Medical Campus, Colorado School of Public Health. “If other studies confirm these findings, gut microbiota profiles might be incorporated into obesity risk assessment tools to identify children who would benefit from early preventive measures before excess weight appears.”
Previous research has increasingly linked the gut microbiome to obesity, with some studies suggesting a causal relationship. To further investigate, University of Colorado researchers collaborated with Merete Eggesbø, MD, PhD, leader of the NoMIC birth cohort at the Norwegian Institute of Public Health in Oslo. The analysis included 165 children from the NoMIC cohort who had BMI measured at age 12.
The NoMIC study, initiated in 2002, is among the earliest birth cohorts to examine the early-life gut microbiome. It enrolled mothers and newborns at delivery and has followed approximately 550 children into adolescence. In the subset analyzed for this report, 20% of the 165 children were classified as overweight or obese by age 12.
Researchers compared BMI at age 12 with gut microbiota samples collected at six time points across the first two years of life: day 4, day 10, one month, four months, one year, and two years. They used 16S rRNA gene sequencing to characterize the gut bacterial communities and examined whether specific taxa at each time point predicted later BMI.
The study identified qualitative differences in gut microbiota composition at day 10 and at two years that were associated with BMI z-scores at age 12. BMI z-scores adjust weight for a child’s age and sex and provide a standardized measure for comparing growth. The investigators also assessed how much variation in childhood BMI z-scores could be explained by early-life gut microbiota taxa.
“Although some relationship between early-time-point microbiota and later BMI existed, the association grew stronger with age,” Dr. Stanislawski explained. “The signal was stronger at one year and strongest at two years. Importantly, the children who later became overweight or obese did not show elevated BMI z-scores at age two, suggesting the gut microbiota phenotype preceded any clear signs of excess weight. Because diet shapes the microbiota, these microbial signatures may also reflect dietary patterns that precede obesity.”
The research also raised a cautionary note. Some bacterial taxa typically considered beneficial were associated with higher childhood BMI in this cohort. This finding underlines our incomplete understanding of how gut colonization in early life affects long-term metabolic health and suggests that the effects of specific microbes may vary by context, host factors, or developmental stage.
Dr. Stanislawski noted that routine probiotic use in infants deserves careful consideration. “During pregnancy and early infancy, some clinicians recommend giving babies probiotics,” she said. “However, repeatedly introducing the same strains might impede natural colonization by a broader array of microbes that could be important for healthy development. A practical way to support a diverse gut microbiota is a balanced diet rich in a variety of vegetables and dietary fibers, which provide substrates for many different bacterial groups.”
The authors acknowledge limitations: the analysis focused on children of Norwegian descent, and findings should be validated in diverse populations. If replicated, early-life gut microbiota profiling could become a component of strategies to identify and support children at risk for obesity. “Early identification matters because preventing obesity is generally easier than reversing it,” Dr. Stanislawski said. She added that laboratory follow-up studies may help clarify mechanisms linking early microbiota patterns to later metabolic outcomes.
Funding: This research was supported by the Howard Hughes Medical Institute.
The authors report no financial or other conflicts of interest.
Source: ASM
Publisher: Organized by Neuroscience News.
Image credit: ASM
Original research: mBio article “Gut Microbiota in the First 2 Years of Life and the Association with Body Mass Index at Age 12 in a Norwegian Birth Cohort” by Maggie A. Stanislawski et al., published October 2018. DOI: 10.1128/mBio.01751-18
Abstract
Gut Microbiota in the First 2 Years of Life and the Association with Body Mass Index at Age 12 in a Norwegian Birth Cohort
Childhood obesity is a growing global concern. Emerging research points to the early-life gut microbiota as a potential contributor to obesity risk and one possible mechanism for the transmission of obesity vulnerability across generations. This study examined the infant gut microbiota at six time points during the first two years (days 4, 10, 30, 120, 365, and 730) and evaluated associations with BMI z-scores at age 12 in a prospective Norwegian cohort (n = 165). Using 16S rRNA gene sequencing, taxonomic phylogeny at day 10 and at two years was significantly associated with childhood BMI. In this cohort, gut microbiota taxa at two years explained a substantial portion of the variation in BMI at age 12. The taxa that best predicted later BMI overlapped with maternal taxa associated with maternal overweight/obesity and excessive gestational weight gain. These results suggest that the infant gut microbiota, particularly at two years, may provide early information useful for identifying children at elevated risk for obesity.
Importance: Understanding how early-life gut microbiota relates to later obesity could enable targeted prevention. This study shows an increasing association between the microbiota from early infancy through two years and BMI at age 12, offering preliminary evidence that gut microbiome profiling at two years may help pinpoint youth at higher long-term risk for obesity and guide early interventions.