Toddlers’ gut microbiota predicts obesity by the age of five, according to study

22 May 2023 --- French scientists have found a link between toddlers’ gut bacteria and a prediction of obesity by the age of five, predicted by Body Mass Index (BMI). The study evidences that the bacteria Firmicutes and Bacteroidetes are directly involved with obesity, as individuals with higher levels of Bacteroidetes were shown to be leaner. 

Presented at the 30th European Congress on Obesity, the scientists also suggest that differences in bacteria in obese individuals might be explained by changes in the gut microbiota in early childhood.

“What surprised us the most is that differences in the gut microbiota composition observed in the adult obesity population are already observed in early childhood before the onset of overt obesity and all its associated metabolic complications,” Gaël Toubon, lead researcher of the study and a Ph.D. candidate at Inserm, Université Paris Cité and Université Sorbonne Paris Nord, France, tells NutritionInsight.

“The gut microbiota is emerging as an important early-life factor able to influence weight gain in childhood and later life. Our findings reveal how an imbalance in distinct bacterial groups may play an important role in the development of obesity,” he adds.

Children with a higher ratio of Firmicutes to Bacteroidetes will absorb more calories and be more likely to gain weight, says Toubon.Down to bacteria
The gut microbiota also influences disruptions linked to several adverse health conditions that can occur later in life.

“The development and maturation of the gut microbiota are highly related to the development of the immune, endocrine and metabolism systems. A perturbation of the development of the gut microbiota and its cross-talk with the host systems can lead to conditions in later life such as inflammatory bowel disease, type 1 diabetes and childhood obesity,” adds Toubon. 

“To date, there is not enough evidence in the research to assess the part of each factor, although these factors are known to play a significant role in shaping the gut microbiota.” 

The researchers investigated changes in toddlers’ gut microbiome between two and five years old and included preterm infants. Stool samples were collected when the infants reached the age of 3.5 and a positive association between BMI and the ratio of Firmicutes to Bacteroidetes gut bacteria was measured.

“The reason these gut bacteria affect weight is because they regulate how much fat we absorb,” explains Toubon. “Children with a higher ratio of Firmicutes to Bacteroidetes will absorb more calories and be more likely to gain weight.”

Furthermore, they found six specific bacteria that predicted BMI scores. A lower level of Eubacterium hallii group, Fusicatenibacter and Eubacterium ventriosum group in the gut showed a higher risk to increase BMI. A higher level of Eggerthella, Colidextribacter and Ruminococcaceae CAG-352 showed lower BMI scores.

The researchers further note that some types of bacteria were associated with speeding up the progression of BMI scores while others protected against it. 

“These findings suggest that what matters with the gut microbiota is not only a question of which bacteria are involved, but also what they are doing,” explains Toubon.

Interest in infant gut healthThe researchers found no difference in the gut microbiome depending on dietary choices.
The researcher found no impact on BMI scores whether or not the child was born prematurely. 

Recently, NutritionInsight spoke with industry leaders on the gut microbiome’s role in infant health and how probiotics may contribute to health benefits in immunity and the digestive tract for the first years of life while highlighting the importance of a nutritious diet.

“Macronutrients such as protein, carbohydrates and fat and micronutrients, including many vitamins and minerals, docosahexaenoic acid and arachidonic acid are all critical for an infant’s normal growth and development. They remain the mainstays of ingredients for infant formulas,” Aaron Feinman, global business insights manager at DSM Health, Nutrition & Care, previously told us.

“We did not see any differences in gut microbiota diversity at 3.5 years according to food patterns (healthy vs. unhealthy) at two years. Of note, when we adjusted our models also accounting for food patterns at two years, we did not see any difference in our results regarding the BMI for the ELFE (French Longitudinal Study for Childhood) cohort,” notes Toubon.

He concludes that further research is needed to “drill down into the specific bacterial species that influence risk and protection and better understand when the switch to an obesity-favorable gut microbiota may take place, and therefore the right timing for possible interventions.” 

By Beatrice Wihlander

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