Almost everyone knows someone who is affected by type 2 diabetes, the type of diabetes commonly linked to obesity. Currently more than 30 percent of adult Americans are considered obese, defined as having a body mass index greater than 30. At the core of type 2 diabetes is insulin resistance. After we eat, our blood glucose rises; insulin is necessary to stimulate tissues to absorb excess blood glucose.
In an individual with insulin resistance, tissues do not respond well to insulin, and glucose accumulates in the blood. This increased blood glucose, also called hyperglycemia, can cause a number of complications up to and including diabetes.
Dr. Jennifer Zwetsloot, adjunct professor for the evening campus, has been studying the mechanisms responsible for insulin resistance in muscle. Most of her work focuses on insulin action in the muscles of obese patients, but she also was able to participate in a number of studies investigating other aspects of insulin resistance, such as fat metabolism in insulin resistance caused by burn trauma, and the role of exercise in reversing insulin resistance.
Fat as an energy source
"What is most interesting about our recent study is that it supports the idea that increasing fat breakdown may decrease insulin resistance in muscle," said Dr. Zwetsloot. "It's exciting to be part of research that gives us a better understanding of insulin resistance, and that may result in new ways to prevent and treat the condition, especially if it advocates exercise."
The jury is still out, but decades of metabolic research suggests that exercising at a moderate pace for longer periods more effectively burns fat than short, intensive exercise.
Zwetsloot's studies used either exercise or an anti-diabetic medication to decrease insulin resistance. In both cases, the treatments also caused an increase in fat breakdown. The studies acknowledge that more work needs to be done to fully understand insulin resistance, but suggest that increasing fat use as an energy source (such as by exercising) may help to alleviate insulin resistance.
Zwetsloot, who earned her Ph.D. in bioenergetics at East Carolina University, Greenville, N.C., admits to being driven. She co-authored three papers on fat, insulin and pediatric burn-trauma victims in 2007 alone. "What motivates me, and what I try to instill in my students, is that the difference between ordinary and outstanding is a personal choice. Most remarkable accomplishments have been done by someone who is no more capable than anyone else; they just chose to apply themselves. I hope that someday others will say that she was outstanding in her field, and not because they saw me picking corn (Get it? Outstanding in her field? Picking corn?)"
Zwetsloot's students think she's brilliant, too, if not always funny.
Zwetsloot's most recently co-authored study, "Insulin Sensitivity is Related to Fat Oxidation and Protein Kinase C Activity in Children With Acute Burn Injury," can be found in the Journal of Burn Care & Research, June 3, 2008.