Opposite changes in circulating adiponectin in women with bulimia nervosa or binge eating disorder

Adiponectin is a recently discovered peripheral peptide that is secreted exclusively by differentiated adipocytes. It has been shown to enhance insulin sensitivity, control body weight, regulate lipid homeostasis, and prevent atherosclerosis. Dysregulation of both lipid and glucose metabolism and changes in body weight and body fat mass have been reported in bulimia nervosa (BN) and/or binge eating disorder (BED); hence, investigation of adiponectin secretion is of obvious interest in these eating disorders. To this purpose, we measured plasma levels of adiponectin, glucose, cholesterol, triglycerides, and thyroid hormones in 60 drug-free women, including 20 patients with BN, 20 patients with BED, and 20 healthy controls. Compared with healthy women, BN women exhibited significantly increased circulating adiponectin levels (P < 0.002) and cholesterol concentrations (P < 0.005), whereas BED women had significantly reduced plasma levels of adiponectin (P < 0.005) and increased concentrations of glucose (P < 0.01), cholesterol (P < 0.05), and triglycerides (P < 0.02). Moreover, plasma levels of adiponectin were significantly correlated to the frequency of binge/vomiting episodes (r = 0.65, P = 0.002) in bulimics but not to the frequency of bingeing in BED patients. Because we did not include a group of obese patients who did not binge eat, the specificity of our findings in the BED should be considered cautiously. However, on the basis of present results, it is tempting to speculate that the increased production of adiponectin in BN may represent a compensatory mechanism to counteract the possible development of insulin resistance, whereas the decreased secretion of adiponectin in individuals with BED may be a risk factor for the development of glucose intolerance.