A useful marker points to binge-eating episodes, not purging.
Reprinted from Eating Disorders Review
May/June 2012 Volume 23, Number 3
©2012 Gürze Books
Amylase, an enzyme active in digestion of carbohydrates, is a useful marker of purging behavior. The normal serum amylase level ranges from 23 to 85 international units per liter (U/L). In a recent study, elevated serum amylase levels in bulimia nervosa (BN), associated with increased salivary gland size and self-induced vomiting in some patients, provided a possible marker of symptom severity.
Barbara E. Wolfe, with colleagues Drs. David C. Jimerson, Adrian Smith, and Pamela Keel, designed a study to assess whether serum hyperamylasemia in BN is more closely associated with binge-eating episodes involving consumption of large amounts of food or with purging behavior (Physiol Behav 2011; 104:684).
Study participants were divided into three groups: 26 women with BN; 14 women with “purging disorder” (PD), a subtype of eating disorder not otherwise specified that is defined by recurrent purging in the absence of objectively large binge eating episodes; and 32 healthy female controls with no history of an eating disorder. There were no significant differences in age or body mass index (BMI, kg/m2) across the groups. The clinical groups reported similar frequencies of self-induced vomiting behavior and none were taking psychotropic medications. Serum samples were obtained after an overnight fast and were assayed for alpha-amylase using an enzymatic method.
Levels were highest among women with BN
Serum amylase levels were significantly elevated in women with BN (60.7 U/L), compared to 44.7 U/L; (P<0.02) in the purging disorder group, and to 49.3 U/L (P<0.05) in the control group. The authors concluded that the study’s findings suggest that it is recurrent binge eating involving large amounts of food, rather than self-induced vomiting, which contributes to elevated serum amylase values in patients with BN.