Ghrelin response to hedonic eating in underweight and short-term weight restored patients with anorexia nervosa

Introduction Recently, anorexia nervosa (AN) has been conceptualized as a reward-related disorder, and brain imaging studies have shown functional and structural abnormalities in areas of the brain involved in reward processes in both acute and recovered AN patients. However, the role of endogenous biochemical mediators, such as Ghrelin, in the modulation of reward processes has been poorly investigated in this eating disorder. Objectives Hedonic eating, that is the consumption of food exclusively for pleasure and not to maintain energy homeostasis, is a useful paradigm to investigate the physiology of food-related reward. Aims We assessed the Ghrelin response to food-related reward in symptomatic AN women in order to further explore the modulation of reward processes in this severe and debilitating disorder. Methods Plasma levels of Ghrelin were measured in 7 underweight and 7 recently weight-restored satiated AN patients before and after the ingestion of a favorite (hedonic eating) and non-favorite (non-hedonic eating) food. Ghrelin responses were compared it that of previously studied healthy controls. Results We found that in satiated underweight patients with AN plasma Ghrelin levels progressively decreased after the exposure and the consumption of both the favorite and non-favorite food whereas in satiated weight-restored AN patients and satiated healthy controls plasma Ghrelin concentrations significantly increased after the exposure to the favorite food and after eating it, but decreased after the non-favorite food. Conclusions These results suggest a derangement in the Ghrelin modulation of food-related pleasurable and rewarding feelings, which might sustain the reduced motivation toward food intake of acute AN patients.