When Sarah Comstock, Ph.D., talks about her research, her purpose behind it is clear.
“The first 1,000 days of life, from preconception to the first two years, really set up an individual for success, health and proper development,” said Comstock, a Michigan State University associate professor in the Department of Food Science and Human Nutrition. “Being able to help everyone get this great start in life is truly important to me and gets me excited and up every day to come to work to do this research.”
Much of her research centers around child development and how maternal health influences it, examining specifically the roles nutrition, metabolites and gastrointestinal microbiota — the collection of bacteria and other microorganisms supporting gut health — play before and during the beginning stages of a child’s life.
Her dedicated leadership in these areas have earned her multiple honors, including the Peter Hartmann Mid-Career Award for Impact on Research and Mentorship she received in December 2024 from the International Society for Research in Human Milk and Lactation, which recognizes a mid-career member of the society who’s demonstrated an exemplary record of research and mentorship in the field of human milk and lactation research.
It's also led to numerous funding opportunities, such as a 5-year, more than $3 million grant from the National Institutes of Health (NIH). Announced in 2023, the project is entering its third year and explores the mechanisms for why maternal obesity serves as a strong predictor of offspring obesity.
Comstock, whose work is also supported by MSU AgBioResearch, said the makings of the project began with her involvement in Child Health Advances from Research with Mothers (CHARM), an alliance of scientists and health providers from the University of Michigan, Wayne State University, MSU, Henry Ford Health and Michigan Department of Health and Human Services. The goal of CHARM is to improve maternal and child health through studies observing mothers and their children from pregnancy into childhood.
That’s where she met Andrea Cassidy-Bushrow, Ph.D., an epidemiologist and senior scientist in the Department of Public Health Sciences at Henry Ford Health. Comstock and Cassidy-Bushrow collaborated on projects together and saw an opportunity to engage with two pregnancy and birth cohorts made up of women and children that would provide sufficient sample sizes depicting the multifactorial contributors to obesity during the pre-, peri- and postnatal periods.
“What that means is we’re looking during pregnancy, around the time of birth and in infancy to understand some of the factors contributing to the potential development of obesity in children,” Comstock said.
Cassidy-Bushrow said the Henry Ford Health + Michigan State University Health Sciences partnership offers a chance for scientists from different backgrounds to learn more about how obesity transpires among people across Michigan.
“From this collaboration, we’re getting data and perspectives from people in different parts of the state, which has been good because it’s a big state and there are a lot of differences across it,” Cassidy-Bushrow said. “The expertise across institutes has been valuable too. Dr. Comstock comes from the nutritional side, and my team comes from more of the epidemiological side, so it’s been nice to have those opportunities to bring different disciplines together.”
According to 2017-2018 data from the National Health and Nutrition Examination Survey administered by the Centers for Disease Control and Prevention, obesity affects 42.4% of U.S. adults and 19.3% of U.S. children and teens ranging from 2 to 19 years old.
Comstock said she hopes the information gathered from this project will be used to identify mechanisms by which obesity develops and to find solutions that would prevent its occurrence early in life.
Researchers from the team, including Jean Kerver, Ph.D., an MSU associate professor in the Department of Epidemiology and Biostatistics, and Sara Santarossa, Ph.D., a Henry Ford Health assistant scientist in the Department of Public Health Sciences, are currently collecting data on several potential elements they suspect may prompt the onset of obesity in children.
The first is the composition of an infant’s gut bacterial community. Initial findings suggest that the maternal body mass index (BMI) plays a part in the makeup of an infant’s gut microbiome, and an infant’s gut microbiome at 1 month old is associated with childhood obesity status at 2 years old. However, the team is monitoring through its research if and how these two instances correlate.
“There are — for ease — certain ‘bugs’ in the microbiome that stand out as being associated with obesity,” Cassidy-Bushrow said. “It’s not enough just to say which bugs, though. It’s why those bugs. We’re really trying to figure out the functionality of them and what they’re doing that might predispose people to obesity.”
The second component is antimicrobial resistance. Comstock said she and her colleagues are studying how certain antibiotics impact the gut microbiome and what role they may play in increasing the risk of obesity.
“There’s a lot of focus right now on the problems antimicrobial resistance poses for health, but we often don’t think about why this burden develops,” Comstock said. “Sometimes, it’s just from these simple exposures where an individual develops a resistance that can then persist, and when they need an antibiotic, that persistence rears its head, and the antibiotic can’t be functional.
“We’re trying to understand if exposure to certain antibiotics during the pre-, peri- and postnatal periods puts a child at increased risk for resistance later in life or contributes to changes in body size during childhood.”
Maternal metabolism is the third potential influence researchers are seeking more information on to determine its stamp on child obesity. Pregnancy alters metabolism, and the group is interested in understanding how metabolites — compounds that are products of metabolism — vary among mothers with different pre-pregnancy BMIs and if those compounds are associated with child development.
Each cohort — one being operated through MSU and the other through Henry Ford Health — will contribute sample sizes of approximately 300 mother and child pairs, and results will be stratified based on each mother’s pre-pregnancy BMI status into the categories of normal weight, overweight and obese.
“When people study groups of adults, they don’t think about stratifying individuals; they just look at the overall impact of obesity,” Comstock said. “With our approach, we’re paying attention to whether some of these mechanisms that contribute to childhood obesity differ depending on a mom's BMI status pre pregnancy.
“One of the reasons we think this will be true — and we're trying to gather evidence for this now — is because metabolism is so different in individuals who have a large amount of adipose tissue, or who have obesity. We're really interested in breaking these groups apart and looking at them separately rather than just bundling everyone into a single analysis.”
In June 2024, the team published a preliminary paper detailing distinctions found in the gut microbiome among women with different pre-pregnancy BMIs. It also provided a further understanding of the relationship between the socioeconomic characteristics and BMI of pregnant women. Comstock said a second preliminary paper is planned to be submitted for publication later this year.
In addition to aiding Michigan residents who may be susceptible to obesity at a young age, Comstock said funding for this project has made it possible for undergraduate and graduate students to conduct significant research at a large-scale.
Kiersten Korber, an MSU doctoral student studying human nutrition, and Alyssa Cosio, an MSU undergraduate student studying nutritional sciences, said they’ve witnessed the societal impact their research can create and have appreciated being able to collaborate on this project.
“It’s an honor to be part of research that has the potential to make a lasting impact on maternal and infant health,” Korber said. “Knowing that our work not only advances scientific understanding but also has the power to improve real-world health outcomes is incredibly fulfilling.”
“My research experience has been filled with great mentorship that has included a lot of support and guidance,” Cosio said. “I’ve always been interested in research as we constantly hear about its advances in the news, journal articles and our daily lives. It’s fulfilling to be a part of the process, learn skills I wouldn’t normally learn in the classroom, and contribute to society by providing scientifically backed information that can help a large population of people.”