Insulinogenic index at 15 min as a marker of stable eating behavior in bulimia nervosa

The metabolic underpinning of eating disorders: A systematic review and meta-analysis of insulin sensitivity

BACKGROUND

A recent study reported a positive genetic correlation between anorexia nervosa and insulin sensitivity using data from genome-wide association studies. Epidemiological studies have, on the other hand, suggested that bulimia nervosa and binge-eating disorder are associated with decreased insulin sensitivity. The aim of this study was to conduct a systematic review and meta-analysis of insulin sensitivity across the spectrum of eating disorders.

METHODS

EMBASE, Medline, and PsycINFO were searched for all relevant studies published until January 2017, and retrieved studies were assessed for eligibility by two independent reviewers as per predefined inclusion criteria. The associations between eating disorder subtypes and insulin sensitivity were analysed separately. Individual effect sizes were standardized, and a meta-analysis was performed to calculate a pooled effect size using random effects.

RESULTS

Of 296 citations retrieved, 22 studies met the inclusion criteria, and 12 studies had appropriate data for meta-analysis. Using the random effects model, the pooled effect size (95% confidence interval) was 1.66 (0.79, 2.54) in people with anorexia nervosa (n = 340) and -0.57 (-0.80, -0.34) in people with bulimia nervosa (n = 120) and binge-eating disorders (n = 3241).

INTERPRETATION

Anorexia nervosa is associated with increased insulin sensitivity whilst bulimia nervosa and binge-eating disorders are associated with decreased insulin sensitivity. The possible mechanism underpinning these findings needs to be determined.

From disordered eating to addiction: the "food drug" in bulimia nervosa

The high prevalence of substance abuse in individuals with bulimia nervosa (BN) and the pervasive symptom substitution in many types of drug addiction suggest that a number of substances--including food--can impair an individual's self-control, even in the presence of negative consequences. Nonetheless, the neurobiological similarities between BN and drug addiction are not clearly established. This review explores how the specific eating patterns seen in BN (binge eating and purging, with intermittent dietary restriction) are particularly addictive and differentiate BN from other eating disorders and obesity. A number of peripheral and central biological aberrations seen in BN may result in altered reward sensitivity in these individuals, particularly through effects on the dopaminergic system. Neurobiological findings support the notion that BN is an addictive disorder, which has treatment implications for therapy and pharmacological manipulations.

Serum amylase in bulimia nervosa and purging disorder: differentiating the association with binge eating versus purging behavior

OBJECTIVE

Elevated serum amylase levels in bulimia nervosa (BN), associated with increased salivary gland size and self-induced vomiting in some patients, provide a possible marker of symptom severity. The goal of this study was 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.

METHOD

Participants included women with BN (n=26); women with "purging disorder" (PD), a subtype of EDNOS characterized by recurrent purging in the absence of objectively large binge eating episodes (n=14); and healthy non-eating disorder female controls (n=32). There were no significant differences in age or body mass index (BMI) across groups. The clinical groups reported similar frequency of self-induced vomiting behavior and were free of psychotropic medications. Serum samples were obtained after overnight fast and were assayed for alpha-amylase by enzymatic method.

RESULTS

Serum amylase levels were significantly elevated in BN (60.7±25.4 international units [IU]/liter, mean±sd) in comparison to PD (44.7±17.1 IU/L, p<.02) and to Controls (49.3±15.8, p<.05).

CONCLUSION

These findings provide evidence to 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 BN.

Towards a physiologically based diagnosis of anorexia nervosa and bulimia nervosa

Diagnosis of anorexia nervosa (AN) and bulimia nervosa (BN), while including such physiological data as weight and the reproductive status of the individual, are primarily based on questionnaires and interviews that rely on self-report of both body-related concerns and eating-related behaviors. While some key components of eating disorders are psychological and thus introspective in nature, reliance on self-report for the assessment of eating-related behaviors and nutritional status lacks the objectivity that a physiologically based measure could provide. The development of a more physiologically informed diagnosis for AN and BN would provide a more objective means of diagnosing these disorders, provide a sound physiological basis for diagnosing subclinical disorders and could also aid in monitoring the effectiveness of treatments for these disorders. Empirically supported, physiologically based methods for diagnosing AN and BN are reviewed herein as well as promising physiological measures that may potentially be used in the diagnosis of AN and BN.

Glucose tolerance predicts short-term refeeding outcome in females with anorexia nervosa

OBJECTIVE

Little is known about biologic predictors of refeeding outcome in anorexia nervosa (AN). Because nutritional status mirrors glucose metabolism during an oral glucose tolerance test (OGTT) in AN, this study investigated whether pretreatment glucose response patterns during the OGTT might be associated with refeeding progress in patients with AN.

METHODS

Sixty-four female patients with anorexia (33 restrictors and 31 binge/purgers) and 13 healthy control subjects underwent an OGTT before nutritional rehabilitation, including desensitization to fear of energy intake of 1000 to 1600 kcal/day. Patients were divided into flat-type responders, impaired glucose tolerance (IGT)-type responders, and normal-type glucose responders. Daily energy intake, weekly weight gain, and the duration of desensitization period were evaluated until the 12th week.

RESULTS

The patients with anorexia consisted of 20 flat-type, 21 IGT-type, and 23 normal- type responders. Normal-type responders required a shorter time to complete the desensitization period than other responders (p = .003 for restrictors, p < .001 for binge/purgers). In terms of refeeding progress, significant group effects for daily energy intake and weekly weight gain were evident in restrictors (p = .006, p = .028, respectively) and binge/purgers (p < .001, p = .003, respectively); normal-type responders showed good refeeding progress compared with other responders in both AN subtypes.

CONCLUSIONS

The present study found a close relationship between pretreatment glucose responses, therapeutic progress of desensitization to fear of energy intake, and refeeding progress in both AN subtypes. Our findings suggest that glucose tolerance may be a useful predictor of short-term refeeding outcome in this disorder.