Dr. Sarah J.Carnahan Craig PhD

Mouth Microbiome Linked to Childhood Obesity

MedicalResearch.com Interview with:

Dr. Sarah J.Carnahan Craig PhD

Dr. Carnahan Craig

Dr. Sarah J.Carnahan Craig PhD
Postdoctoral Scholar
Makova Lab
Biology Department
Center for Medical Genomics
Penn State University

 MedicalResearch.com: What is the background for this study?

Response: This study stems from a long standing collaboration with pediatrician, Ian Paul at Penn State Hershey Medical School (and a co-author on this paper). Ian is very interested in understanding and preventing childhood obesity. It also is part of a much larger, collaborative study objective, lead by Ian and Leann Birch (another co-author), to understand social/behavioral contributors to childhood obesity, how a responsive parenting intervention can prevent childhood overweight/obesity, and the biological factors that contribute to the disease. This is an important research area as childhood obesity is a public health problem — one in three children are overweight or obese. A fuller understanding of factors that contribute to childhood obesity, how to identify children who are at risk for developing childhood obesity, and methods to prevent childhood obesity are of critical importance.

MedicalResearch.com: What are the main findings?

Response: The main finding from this paper is that the oral microbiota (the collection of bacteria that live in the mouth) are significantly related to young child growth patterns. The surprising part of this finding was that we observed this result with the oral microbiota and not the gut microbiota. The oral microbiota (in comparison to the gut microbiota, which has been associated with obesity in many previous studies) are largely understudied, especially in young children. The gut microbiome we found to be strongly influenced by diet; when the two are considered together, there is a significant relationship with child growth patterns.

Additionally, our team developed novel statistical methods to use child growth curves as a more comprehensive outcome rather than an outcome of weight at a single time point (i.e. it uses more of the information about how a child is growing). These methods allow us to better detect the relationship between child growth and the microbiota; they increase our power. 

MedicalResearch.com: What should readers take away from your report?

Response: Readers should take away that there are many factors that contribute to obesity and obesity prevention – along with a healthy diet and exercise, biological factors, such as the microbiota for instance, could potentially be an important consideration. Additionally, we’re in the early stages of truly understanding how these microbes influence health. Importantly, we are unable to make any kind of causal conclusions – meaning we don’t know if the microbes are influencing the growth patterns, is health/environment influencing the microbes, or is it both directions.  

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

Response: One of the limitations of this study is that it looks at the microbiota at a single time point, at two years after birth –  this is a dynamic community, so we are really only seeing a snapshot of what is happening. Additionally, the study is retrospective in that the microbiota is sampled at two years and the growth trajectory is made of measurements from birth through two years. Because of this, we might be missing important dynamics happening earlier in life. A more comprehensive study would be to sample the microbiota at all the time points you are sampling growth, health, and other information — this is a study we are currently doing. We hope that by building on this study and examining the microbiota (both oral and gut) longitudinally and in concert with the social, environmental, and health data that we will be closer to a fuller understanding, which could potentially identify children who are most at risk of developing childhood obesity and be prime candidates for obesity intervention programs.  


Sarah J. C. Craig, Daniel Blankenberg, Alice Carla Luisa Parodi, Ian M. Paul, Leann L. Birch, Jennifer S. Savage, Michele E. Marini, Jennifer L. Stokes, Anton Nekrutenko, Matthew Reimherr, Francesca Chiaromonte, Kateryna D. Makova. Child Weight Gain Trajectories Linked To Oral Microbiota Composition. Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-018-31866-9

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Last Updated on September 19, 2018 by Marie Benz MD FAAD