Abstract
Anorexia nervosa is the third most common illness among adolescent females. Approximately one half the cases of anorexia nervosa have been suggested to be activity-induced. Various animal studies have been used to study human anorexia, particularly the activity-based anorexia model (ABA). The ABA paradigm consists of diet restriction and liberal access to activity, which ultimately results in a rapid decrease in both body weight and food intake paradoxical to the significant increase in activity. Because resistant starch (RS) has been shown to initiate a lower rise and a steady level of post-prandial blood glucose, it was hypothesized that a diet containing RS would reduce the severity of the anorexia associated with the ABA model. In this study, 56 five-wk old male Sprague-Dawley rats were assigned to 8 groups. Animals were fed a control diet (C-diet) or a RS-diet, on an ad libitum or a restricted-feeding (one 90min meal per day) schedule, and allowed 22-hr of access or no access to activity wheels. The study ended when majority of the ABA rats reached <75% of their pre-experimental bodyweights. Within 4 days of the experiment, ABA rats on the RS-diet lost an average 66g of bodyweight compared to an average loss of 31g in the C-diet (p<0.01). ABA rats on the RS-diet ran 31% more (NS), despite consuming 30% fewer calories per kg body weight, than those on the C-diet (p<0.01). ABA rats fed the RS-diet had 3.97 times higher levels of plasma norepinephrine (NE) compared to their associated controls (p<0.0001); ABA rats fed the C-diet had only 1.4 times the NE level of their corresponding controls (NS). All RS-fed rats had an average of 17-50% less fat pad (brown, perirenal, epididymal, & retroperitoneal) weights compared to C-fed rats (p<0.02). Resistant starch exacerbates rather than mitigates the responses to the ABA paradigm.
|
