Karen E. Peterson

Karen E. Peterson

Professor and Chair, Department of Nutritional Sciences

From Metabolomics to Epigenetics, Nutrition Is about More Than Food

Karen Peterson spends a lot of time thinking about how children grow and grow up. As professor and chair of the Nutritional Sciences department at Michigan Public Health, Peterson wants public health to have a greater role in preventing disease in children and in offering effective interventions when things have gone off track.

"Most children are healthy and can adapt well to their environment as they grow," Peterson says. But many things can push a child off track. "Infections, hunger, an obesogenic food supply, toxicants. And the effects can be more adverse in sensitive periods—periods of growth characterized by dramatic changes in biology, behavior, and social environments."

Peterson's research focuses on these sensitive periods. She studies the biological, social, and environmental influences on growth during sensitive transitions—from womb to early infancy, preschool to school, puberty, and late adolescence into young adulthood. "During these periods, a child's physiologic growth and maturation is accelerated, and the child also has to adapt rapidly to the environment. If something even small goes wrong during one of these periods, it can set the child up for chronic disease later in life."

Peterson wants us to understand just how important education and preparation can be. "Public health practitioners have tremendous opportunities—via interventions during sensitive periods when a child is developing rapidly— to help that child remain on a normal course. Even small changes can shift the course dramatically," she says.

Global Partnerships

This intersection of behavior and biology in child development is important for understanding the potential of nutrition to contribute to lifelong health, Peterson explains. "You can be exposed in the womb to certain toxicants yet be less at risk of lifelong effects if your mother had an adequate intake of vital nutrients during pregnancy."

Mexico has been a focal point for Peterson's interest in the relationship between toxicant exposure and chronic disease. Peterson and her research team—including colleagues from Instituto Nacional de Salud Pública de Mexico (INSP)—have spent 22 years and counting conducting the Early Life Exposure in Mexico to ENvironmental Toxicants (ELEMENT) study in Mexico City. The project is longitudinal, meaning the same subjects are observed over long periods of time, and comprises three birth cohorts of women—the original recruits from 1994 to 2004, their children now aged 12–22, and a generation of grandchildren currently being born.

The study began two decades ago with observing the impact of endocrine-disrupting chemicals and metals on metabolic and cognitive development in participants. "Now the team is looking at menopause—in the grandmothers—as yet another sensitive developmental transition," says Peterson. In recording the multigenerational effects of toxicant exposure, the recently re-funded ELEMENT study has produced numerous papers and created a valuable repository of data for future studies on diet and toxicant interactions, epigenetics, and metabolic health.

Successful Partnerships

Peterson does most of her work within a "partnership model," engaging community, state, and national public health organizations that already have primary responsibility for carrying out population-based interventions.

In Massachusetts, Peterson and colleagues designed a child-obesity intervention called Planet Health for middle school students in the Boston area. Over a two-year period, Planet Health schools infused basic behavior change messages into their lesson plans: eat more fruits and vegetables, eat healthier fats, be more active, cut down on television. The intervention was a tremendous success, cutting in half the chance that girls in the study would be obese at the end of middle school.

With the Massachusetts Department of Public Health and Blue Cross/Blue Shield of Massachusetts, the study was redesigned for a much larger population. More than 100 schools across Massachusetts adopted Planet Health, and in a field of over 20,000 children, the prevalence of overweight and obesity in boys and girls was reduced from 42.1 to 38.4 %.

Peterson attributes much of the success of these studies to good relationships. "We had strong partners in those four school systems, and we worked closely with teachers to integrate the study into their health curriculum," Peterson says. "Teacher input on curriculum and their commitment to implementation was vital to the study."

The Power of Nutritional Sciences

Nutritional Sciences pay attention to the role of food in society, but nutrition is much more than that. "Nutrition is not synonymous with food," Peterson explains when asked about common misconceptions of her field. "Nutrition is a rich science that's concerned with food but focuses on what happens to those nutrients when they enter your body—how they affect your physiology, your metabolism, your health and well-being."

"We have faculty and students working on topics ranging from how livestock husbandry might affect anemia to risk factors for eating disorders to clinical and community interventions addressing obesity," Peterson says. "Nutrition is truly a hard science," she reminds us, "because it addresses physiological effects on the body with such precision." But nutrition also looks closely at social and cultural influences as well as behavioral outcomes, making it a dynamic interdisciplinary field that appeals to researchers from all kinds of backgrounds.

Despite her many successes in collaborative and interdisciplinary research, Peterson knows the field of nutritional sciences can offer even more. "We know how to produce modest effects through nutrition interventions, but how do we shake up our frameworks and come up with more innovative solutions, new ways of understanding childhood obesity to make some truly big leaps?" Peterson asks.

Some of those leaps are happening right here on campus. Peterson is director of the Momentum Center, an interdisciplinary research center she designed to conduct innovative childhood obesity research. In one large scale multi-collaborative project, for example, Momentum Center investigators from Kinesiology, Public Health, and Architecture and Design are redesigning classrooms and testing the metabolic effects of different activity breaks during the day. "How can we make the classroom more alive and mobile—and therefore healthier?" the research team is asking.

Teaching Nutritional Sciences

Peterson strives to make her courses come alive for students. "I think a lot about why the content matters to them, why they would care, why they would take the time for this course." She wants them to think about how this knowledge will help them make a difference in the world and make a difference in their own career path. "I design my courses to foster future professional development, reminding students that public health practitioners, researchers, and organizations will actually pay them to know and interpret this material. I want them to become experts and professionals in the field."

In a field that is constantly evolving and generating new knowledge, Peterson has to ask every day where nutrition will go next. "Nutrition will continue to change, so the knowledge is important. But my students need the ability to examine and critique our current paradigms so that they can advance the field and be prepared for those inevitable shifts in how we actually think about nutritional sciences."

Peterson looks to her students to identify the open questions, the modes of thinking that have not yet entered the field, let alone garnered attention. "I want my students to remember that scientific results are not necessarily 'truth' and might capture only a piece of the puzzle. They are a step on the way to understanding, and the very methods we used to arrive at these results should remain open to reflection and reinvention."