On The Ground

Adipocytes are specialized cells that store fat and release signaling molecules that affect appetite and metabolism. Hei Sook Sul, a professor of nutritional sciences and toxicology (NST), studies the contribution of two components in the development of obesity: adipocyte stem cells and adipose lipid metabolism. Obesity results from the expansion of adipose tissue caused by increasing the fat content and number of adipocyte cells. Controlling this expansion would help control obesity. Fatty liver tissue (lipid has been stained red, and liver cell nuclei are stained blue).

Professor Joe Napoli, chair of the Department of Nutritional Sciences and Toxicology, studies the function of two regulatory molecules derived from vitamin A that modulate energy balance, appetite, fat storage (adiposity), and blood glucose control — all of which impact diabetes. (See also Why I Do Science.)

Glucocorticoids are stress hormones that are critical to metabolic adaptation during stress, such as fasting and starvation. Chronic and excess glucocorticoid exposure, however, causes metabolic syndrome, which increases the risk of diabetes and cardiovascular diseases. Jen-Chywan Wang, associate professor of NST, studies the regulation of glucose, lipid, and protein metabolism by glucocorticoids.

Marc Hellerstein, an NST professor, measures fluxes through the complex networks of proteins, metabolites, and cells that are responsible for health and disease. The focus is on obesity, diabetes, and caloric restriction, and the impact of specific substances consumed by humans, such as fructose (as part of a high carbohydrate diet), on risk for disease.

Gregory Aponte, an NST professor, studies nutrient “sensing” and how the gut-brain axis can communicate dietary composition and status to the brain. The gut-brain axis is involved in obesity because it regulates food intake behavior. In one current study, Aponte is evaluating which nutrient compounds have receptors that allow the brain to detect them more quickly, thus making eaters feel full sooner.

Andreas Stahl focuses on molecular mechanisms underlying obesity-related disorders such as diabetes and fatty liver disease. In a recent study he identified two naturally produced compounds that are effective in reducing the uptake of fat by the liver, opening the door to the development of treatments for fatty liver disease, a precursor to diabetes and other obesity-related conditions. Stahl is an associate professor of NST.

As a researcher at the Atkins Center for Weight and Health, Lorrene Ritchie evaluates obesity-prevention interventions with a focus on nutrition policy and the food environment. She is leading an evaluation of the impact that new state beverage standards have on licensed child care, which will inform national policy, and a United States Department of Agriculture study on the impact of nutrition education in the federally funded nutrition program for women, infants, and children.

Patricia Crawford studies the ways in which nutrition programs and policies can improve children’s dietary intake and reduce childhood obesity. In a recent study that policymakers used to craft legislation to improve school nutrition, she identified predictors of increased participation rates in the school meal program and of successful efforts to provide healthier snack foods. Crawford is the director of the Atkins Center for Weight and Health, a Cooperative Extension specialist, and an adjunct professor of public health.