Category: Food

Understanding Obesity — Starting with a Baby’s First Meal

Children who have an obese mother are 2-to-3 times more likely to be obese as well. Ellen Demerath wants to understand why this happens.

“We need to further explore the link between a mother’s weight, her nutrition, and her baby’s weight. We’re trying to cut off childhood obesity very early in the process,” she says.

School of Public Health Professor Ellen Demerath with a one-month old MILK Study participant.
School of Public Health Professor Ellen Demerath with a one-month old MILK Study participant.

The School of Public Health professor has worked throughout her career to understand how a mother’s nutrition may have an impact on a child’s weight. But, in 2012, she noticed a gap in the research — there hadn’t been a large, standardized study to investigate the role of hormones in breast milk on infant weight gain.  

But she needed partners and found her match when she met David Fields at a conference. Fields, an associate professor at the University of Oklahoma College of Medicine, was already gathering samples of breast milk to study the link between the milk and body composition.

The two began working together to develop the MILK (Mothers and Infants LinKed for Healthy Growth) Study, which seeks to understand how breast milk is related to mother and infant weight gain and body composition.

In 2014, Fields and Demerath received $3.6 million from the National Institutes of Health’s National Institute for Child Health and Development for a five-year study and began recruiting their first cohort — 350 moms, who were recruited in pregnancy, and their newborn babies.

“We don’t know enough about what’s actually in breast milk. We know a lot about the benefits of breast milk and breastfeeding, but we don’t really know why these benefits exist,” says Demerath.

Moms and Babies in Science

While Fields created a cohort in Oklahoma, Demerath recruited moms across the Minneapolis/St. Paul area who were patients at HealthPartners clinics. They ranged across body mass indexes (BMI) — normal weight, overweight, and obese.

The mother and baby come to the University of Minnesota’s Center for Neurobehavioral Development (CNBD) at 1 month, 3 months, and 6 months. During the visit, researchers collect the mother’s milk and measure the baby’s muscle and fat amounts using a “pea pod.”

MILK Study coordinator Laurie Foster with a mom and baby at a six-month check up.
MILK Study coordinator Laurie Foster with a mom and baby at a six-month check up.

Facilitating the entire process is study coordinator Laurie Foster, who works with every mother and baby who are part of the study. “Meeting a mom with a newborn is a privilege. I’m part of their life at a very unique and special point in time when a lot is changing for the mom,” says Foster, who has a background in child development, parent education, and family social science. “I’m here to answer the mom’s questions and we talk a lot about what they’re experiencing during the three-hour initial visit while their baby is being measured and data is collected.”

“I’m curious to see how breast milk overall has an impact on their long-term health and their risks for obesity,” says Adrienne Kinde of Roseville, Minn., a mother of two daughters who have participated in the study.

All participants are exclusively breastfeeding at one month, so the results can be easily interpreted. By the three-month visit, some have quit breastfeeding and Demerath and her colleagues can see if a baby’s vitals change as the baby transitions to formula.

The study has also provided further insight into why moms with a higher BMI have more difficulty starting and continuing to breastfeed. The researchers found that women with a higher weight status produced less breast milk and a high blood sugar level in women was a predictor for how much milk would be produced.

What’s in the Milk?

Previous studies have shown that the breast milk of heavier mothers has higher levels of leptin, which is an appetite-suppressing hormone. This causes these women to have lower weight babies. “It’s counterintuitive because these women are more likely to have children who become proportionally heavier as they grow,” says Demerath.

School of Public Health Professor Ellen Demerath measures breast milk samples.
School of Public Health Professor Ellen Demerath measures breast milk samples.

So the MILK Study is investigating the role of hormones in infant appetites and satiation. “Leptin might be related to lower relative growth while a child is breastfeeding, but we’re working to discover how children’s bodies react once they’re off milk. We’re starting to wonder if these kids shoot up in weight once they’re done breastfeeding.”

While the current MILK study runs until 2019 and Demerath will publish further findings, Demerath is already applying for grants so she can continue to follow participants into their toddler years. “We’re thinking that the differences seen in breast milk don’t become evident until later in the child’s life when the child starts to be in control of what he or she is eating.”

The next phase would also explore the connection between a child’s growth and his or her microbiome, which refers to the combined genetic material of the bacteria found in a person’s digestive system. “In the womb, babies have no microbiome in their gut, but through the birthing process and through swallowing breast milk, the microbiome differentiates and grows. By the time infants are two years old, their microbiome looks the same as an adult’s.”

As Demerath aims to understand this, she’s already collecting samples from MILK participants to understand if the microbiome is influenced by the mother’s weight status.

Training Ground

The MILK study has provided an optimal opportunity for School of Public Health students interested in maternal and child health and nutrition to be part of a large-scale, epidemiological study.

School of Public Health student Regina Marino helps take a baby's measurements.
School of Public Health student Regina Marino helps take a baby’s measurements.

Public Health Nutrition MPH student Regina Marino worked on the study through a research assistantship, which includes tuition benefits. “Being part of the MILK study has helped me narrow down my career interests and working with Ellen has shown me what it would be like to work in academia,” says Marino, whose main role in the study was managing the breast milk samples and conducting breast milk maconutrient composition analyses.

She’s also working with Demerath to publish research. “Before being part of the MILK Study, I had only done scientific writing in the classroom and Ellen taught me how to summarize findings in a succinct and concise way.”

Ghazaleh Sadr Dadres is a Maternal and Child Health MPH student who approached Demerath to work on the MILK study to fill a data analysis project requirement. “I learned analytical skills that broadened my knowledge on how to conduct and analyze a large-scale epidemiological study,” says Sadr Dadres, who is now working with Demerath to publish findings about prepregnancy and postpartum characteristics using MILK data. “I had a c-section and I was displeased with that. I want to improve the health of mothers and help them have better pregnancy outcomes.”

And the study’s home at CNBD allows for unique partnerships with researchers across the U of M. The center’s more than 40 members work throughout the health sciences and are looking at all angles of childhood development, from body composition and obesity to brain development and cardiovascular risk.

“As scientists, we have to cross silos to teach each other our languages,” says CNBD Director Dr. Michael Georgieff, who researches the relationship between body composition and brain development.

“Through working with public health researchers, I’ve learned how to link health outcomes to policy. In clinical research, we often have our finding and talk only about that, but working with public health researchers has really forced me to ask, ‘So what are we going to do about this? How can we translate and educate our finding?’ I wouldn’t have a clue how to talk about this if I didn’t have a collaborator like Ellen.”

Collaborations like these allow public health to enter the child development research sphere in new ways. “Many researchers focus solely on the child or the family,” says Demerath. “But public health looks at other factors, such as the social determinants of health, and uses epidemiological study design and methods to understand the full picture.”

Investigating Food Outbreaks

Every year, Minnesota experiences more than 40 foodborne disease outbreaks. The summer months see scores of Salmonella cases or E. coli poisoning, while winter brings norovirus infections by the droves.

SPH student, and Team D member, Tess Peterson (left) with Team D director Carlota Medus (MPH '99, PhD '06).
SPH student, and Team D member, Tess Peterson (left) with Team D director Carlota Medus (MPH ’99, PhD ’06).

The Minnesota Department of Health (MDH) is continuously collecting information on potential foodborne illness outbreaks via routine surveillance, or when a patient, provider, or institution reports a suspected outbreak.

Investigating the source of those outbreaks takes hundreds of hours, many of which are conducted by Team D (“D” for diarrhea), a group in MDH’s Foodborne Diseases Unit made up in large part by School of Public Health students. Team D students are hired to investigate, document, and track outbreaks of foodborne diseases in the state. The program was founded by SPH professor and foodborne disease expert Craig Hedberg in 1996 and has continued to evolve under the direction of Carlota Medus MPH ’99, PhD ’05, and Kirk Smith for the past 21 years.

Identifying an Outbreak

“This is the true epidemiology experience,” says Medus, supervisor of the Foodborne Diseases Unit at MDH. “As part of Team D, you learn everything to do during an outbreak at the state level, and get a complete picture of what happens when you detect an outbreak.”

Amy Saupe (MPH '16) analyzes data from a recent outbreak.
Amy Saupe (MPH ’16) analyzes data from a recent outbreak.

Currently, all of the Foodborne Disease Unit epidemiologists, including Medus, are SPH alumni, and were part of Team D as students before getting hired by MDH. 

“Team D helps with every step of the investigation,” says Medus. Initially, a Team D worker will call a patient and take a detailed epidemiological history of their food intake and possible exposures. “They’ll ask about everything that happened in the seven days before symptoms began,” says Medus.

And, Medus says, Team D members often break open a case. “Since the students are the ones on the phone with patients, they’re often the first to notice if a certain restaurant has been mentioned more than once.”

Unique Experience

Having the chance to solve the mystery of an outbreak is what attracted Krista Bryz-Gornia to Team D. The first-year epidemiology MPH student heard about the program during a student fair before she started in SPH and knew she wanted to be a part of the team.

SPH student and Team D member Luke Magnuson conducts phone interviews.
SPH student and Team D member Luke Magnuson conducts phone interviews.

“I love that we get to see an outbreak or a case from beginning to end. It’s exciting to talk to other student workers when there’s an outbreak and say, ‘Did your patient eat at this restaurant?’ ‘Did they have this symptom?’”

As a fluent Spanish speaker, Bryz-Gornia has conducted bilingual interviews and says MDH has been flexible in letting her balance work and school. Team D staff members work about 20 hours a week from 9 a.m. to 8:30 p.m., often contacting patients in the evening to get information about their illness and symptoms.

“Team D has been a perfect complement to my public health education,” Bryz-Gornia says.

In addition to MDH, the program’s alumni work across the country in such institutions as the U.S. Department of Agriculture and the CDC.

Andrew Beron, MPH ’14, was a Team D member and is now an epidemiologist for the U.S. Virgin Islands Department of Health on the island of St. Croix, where he helps perform Zika surveillance. Beron says his time at Team D was helpful in preparing him for a career in the field.

“Team D is something students at other schools of public health don’t get,” says Beron. “It helped me build so much confidence as an investigator.”

Minnesota Leads the Way

That confidence is what sets Minnesota’s SPH apart from other institutions. “By the mid-1990s it became clear that foodborne infections weren’t going away,” says Hedberg. “What we wanted to do with foodborne disease surveillance was create a student worker team that could participate in surveillance and do routine interviews with individual cases, then the students have both practical experience and the opportunity to work with data they’ve collected.”

Hedberg says other state departments of health and even the CDC have taken note of Team D’s efficiency.

“We developed the model, and others have tried to replicate it,” says Hedberg. “The partnership between the SPH and MDH is still one of the biggest draws to our school for students who want to work in epidemiology.”

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