...Does Stress Play a Role?
Rates of obesity in American children have tripled since the 1970s. According to the most recent data from the Centers for Disease Control and Prevention, nearly 16 percent of American children and adolescents are obese, and about four percent—or 2.7 million children ages two to 19—are severely obese. The implications for our future health and economy are dire. Obese and overweight children and adolescents are more likely to have risk factors for cardiovascular disease as well as asthma, fatty liver disease, sleep apnea, and early signs of type 2 diabetes.
A 2006 study of health care expenditures found that annual medical expenses in the United States for an obese adult were $1,548 more than for a normal-weight adult. Medical expenses for an obese child aged six to 17 were $264 higher.
Researchers don’t know all the factors responsible for the obesity epidemic, but studies suggest chronic stress could be one of them. University of Michigan scientists are studying the relationship in preschool children between stress, comfort food, and obesity. They’re also testing an intervention that may help children better manage stress and in turn reduce the likelihood of their becoming obese.
Who: Julie Lumeng, MD, UM Medical School and UM School of Public Health; Alison Miller, PhD, UM SPH; Karen E. Peterson, ScD, UM SPH; other researchers affiliated with the UM Center for Human Growth and Development and UM Center for Comprehensive Prevention of Obesity in Childhood; and researchers from Michigan State University.
What: Research to identify connections between appetite, behavior, and levels of cortisol and other stress-related hormones in preschool children.
Where: Head Start preschool programs throughout Michigan.
When: Studies began in 2009 and will be completed in 2015.
Why: Eating behaviors established in early childhood often continue into adulthood. Studies show that children who are overweight in preschool are more likely to grow up to be overweight adults.
What researchers know:
- Stress triggers production of a hormone called cortisol that stimulates appetite and shifts food preferences toward high-fat, high-sugar “comfort foods.”
- Research shows that when adults are stressed, they eat more. Some studies suggest kids do the same.
- High-fat, high-sugar “comfort foods” have been shown to reduce the “stress hormone
cascade” in laboratory animals, suggesting that comfort food is therapeutic in animals
because it makes them feel better.
Scientists take saliva samples to measure the amount of cortisol and other stress hormones the human body produces. Higher cortisol levels reflect chronic stress.
- Studies show that young children with behavior problems, frequent tantrums, and difficulty controlling their emotions are more likely to be overweight.
- Children ages five to seven who eat when they’re not hungry (what scientists call “eating in the absence of hunger”) are more likely to be overweight or obese by age nine.
- Most children can learn to regulate their emotions, behavior, and reactions to daily stressors. Parents can learn how to help them do it.
Questions researchers want to answer:
- At what age are stress-associated eating patterns established in children?
- Do children inherit a genetic predisposition to stress-eating behavior from their mothers?
- Is there a link between stress in the home and stress-related eating behaviors?
- Are kids who have more stress—and higher cortisol levels
in response to stress—more likely to eat in the absence of hunger?
- What happens in the human brain when people eat comfort foods?
Is it possible that comfort foods suppress stress hormones in some people but not in others? If so, why?
- Can interventions help preschool children learn to self-regulate their emotions and behavior and thus avoid excessive weight gain?
- What interventions are most effective at preventing obesity in children? If kids learn to calm themselves during tantrums, for example, are they less likely to turn to comfort foods?
- At what age are interventions most effective?
By Sally Pobojewski
Featured Center: NORC
The goal of the Nutrition Obesity Research Center (NORC) at the University of Michigan is to support infrastructure to encourage and enable researchers from preclinical, clinical and translational and population-based disciplines to integrate the newest tools in molecular and cellular biology, neurobehavior and computational biology into their studies related to metabolic health.
The NORC is the only new center funded by the NIH in the latest round of funding and grew out of the Michigan Metabolomics and Obesity Center.