The Role of the Gut Microbiome,Immunity, and Neuroinflammation in the Pathophysiology of Eating Disorders

There is a growing recognition that both the gut microbiome and the immune system are involved in a number of psychiatric illnesses, including eating disorders. This should come as no surprise, given the important roles of diet composition, eating patterns, and daily caloric intake in modulating both biological systems. Here, we review the evidence that alterations in the gut microbiome and immune system may serve not only to maintain and exacerbate dysregulated eating behavior, characterized by caloric restriction in anorexia nervosa and binge eating in bulimia nervosa and binge eating disorder, but may also serve as biomarkers of increased risk for developing an eating disorder. We focus on studies examining gut dysbiosis, peripheral inflammation, and neuroinflammation in each of these eating disorders, and explore the available data from preclinical rodent models of anorexia and binge-like eating that may be useful in providing a better understanding of the biological mechanisms underlying eating disorders. Such knowledge is critical to developing novel, highly effective treatments for these often intractable and unremitting eating disorders.     

Eating Disorders Examination versus Eating Disorders Examination-Questionnaire in adolescents with full and partial-syndrome bulimia nervosa and anorexia nervosa

OBJECTIVE: The current study compared the Eating Disorders Examination (EDE) and the Eating Disorders Examination-Questionnaire (EDE-Q) in adolescents with eating disorders. METHOD: Adolescents (N = 70) with bulimia nervosa (BN; n = 21), partial-syndrome BN (PBN; n = 25), and anorexia nervosa (AN; n = 24) were assessed with the EDE and EDE-Q. RESULTS: Moderate to high correlations were found on all four subscales within and between diagnostic groups. The discrepancy between the EDE and EDE-Q was significantly greater in BN relative to PBN and AN for the Eating Concern subscale. Objective binge episode (OBE) frequency in BN and subjective binge episode (SBE) frequency in BN and PBN were higher with the EDE compared with the EDE-Q. Self-induced vomiting was highly correlated between the two measures. DISCUSSION: Adolescents with BN, PBN, and AN exhibited strong correspondence between the EDE interview and questionnaire formats. However, this consistency was not as pronounced for BN as it was for PBN and AN. The current study lends preliminary credibility to the use of the EDE-Q in adolescent eating disorder samples.     

The clinical presentation of Japanese women with anorexia nervosa and bulimia nervosa: a study of the Eating Disorders Inventory-2

OBJECTIVE: The current study described the clinical presentation of anorexia nervosa (AN) and bulimia nervosa (BN) in Japan utilizing the Eating Disorders Inventory-2 (EDI-2) and assessed whether the clinical profile of eating disorder cases in Japan differs significantly from North American data. METHOD: Statistical comparisons of Japanese AN, BN, and non-eating-disordered (NonED) EDI-2 data were conducted across diagnostic groups and with the North American standardization sample. RESULTS: The Japanese diagnostic groups reported significant between-group differences on all eight EDI-2 subscales. Compared with the standardization sample, all the Japanese groups reported significantly greater maturity fears, the Japanese AN-restricting subtype group (AN-R) reported lower levels of drive for thinness and perfectionism, the Japanese BN group reported lower levels of drive for thinness, and the Japanese NonED Group reported lower levels of drive for thinness and perfectionism but higher rates of ineffectiveness. DISCUSSION: Differences between the Japanese and North American groups suggest that certain cultural differences exist in eating disorder profiles.     

Body-Related Social Comparison and Disordered Eating among Adolescent Females with an Eating Disorder,Depressive Disorder,and Healthy Controls

The purpose of this study was to investigate the association between body-related social comparison (BRSC) and eating disorders (EDs) by: (a) comparing the degree of BRSC in adolescents with an ED, depressive disorder (DD), and no psychiatric history; and (b) investigating whether BRSC is associated with ED symptoms after controlling for symptoms of depression and self-esteem. Participants were 75 girls, aged 12–18 (25 per diagnostic group). To assess BRSC, participants reported on a 5-point Likert scale how often they compare their body to others’. Participants also completed a diagnostic interview, Eating Disorders Inventory-2 (EDI-2), Beck Depression Inventory-II (BDI-II), and Rosenberg Self-Esteem Scale (RSE). Compared to adolescents with a DD and healthy adolescents, adolescents with an ED engaged in significantly more BRSC (p ≤ 0.001). Collapsing across groups, BRSC was significantly positively correlated with ED symptoms (p ≤ 0.01), and these associations remained even after controlling for two robust predictors of both ED symptoms and social comparison, namely BDI-II and RSE. In conclusion, BRSC seems to be strongly related to EDs. Treatment for adolescents with an ED may focus on reducing BRSC.     

Factors Associated with Underweight,Overweight, and Eating Disorders in Young Korean Women: A Population-Based Study

Both underweight (UW) and overweight (OW) conditions are problematic in young women. The aim of this study was to examine the factors associated with extreme weight status and eating disorders (EDs) in young Korean women. A total of 808 women (mean age 22.3 ± 3.4 years) participated, including 144 with UW [Body Mass Index (BMI) < 18.5kg/m²], 364 with NW, and 137 with OW or obesity (BMI ≥ 25kg/m²), and 63 patients with anorexia nervosa (AN) and 100 with bulimia nervosa (BN). Participants completed questionnaires regarding nutrients consumed, eating behaviors, health behaviors, body image, and obsessive-compulsive symptoms with face to face interviews. The associations between the status of participants and the data were analyzed with NW group as a reference. OW status was associated with overeating and with frequent eating. UW status was associated with less frequent overeating and with longer sleep duration. AN status was associated with less frequent consumption of alcohol. BN status was associated with a larger discrepancy between the ideal and current body shape. Both OW status and BN were associated with more obsessive-compulsive symptoms. The results suggested that certain dietary, health, and psychological factors are associated with extreme weight conditions and EDs.     

Health-Related Quality of Life in Spanish Women with Eating Disorders

People with eating disorders show impaired health-related quality of life (HRQoL). We aimed to investigate the relative role of physical and mental factors and stage of change as possible predictors of HRQoL in a group of Spanish women (n = 124) with eating disorders. For this purpose, initial and follow-up data were obtained after 6 months from patients attending an outpatient treatment unit for eating disorders. The determinants of the physical and mental domains of the Medical Outcomes Survey Short-form Health Survey (SF-36) questionnaire were investigated in the total sample and separately based on the eating disorder diagnosis by multiple linear regression. Lower scores in the physical component of the SF-36 questionnaire were associated with the presence of a higher body mass index (BMI) at follow-up as well as a higher score in the “action” component of the Attitudes towards Change in Eating Disorders Questionnaire (ACTA). Conversely, a higher index in the EuroQoL-5D overall quality of life questionnaire (EQ-5D) and the presence of obsessive compulsive disorder were associated with a higher score in the physical dimension. The instrument used demonstrated the ability to assess changes associated with the physical component of these patients over the period studied, and the analysis provided more information and specific data on different aspects of HRQoL, thus allowing a more detailed analysis of the information.     

Eating Disorder in a Hemodialysis Patient: Case Report

Renal replacement therapy may encourage eating disorders in some patients. Hemodialysis requires patients to attend dialysis sessions three times per week, during which time they are weighed pre- and posttreatment, so the importance of limiting "fluid weight" gains to prevent fluid overload and elevated blood pressure are constantly reinforced by the dialysis team. Patients must also follow rigorous therapeutic dietary modifications to prevent the buildup of urea and harmful waste products between treatments. This is a case report of a 30-year-old man receiving renal replacement therapy who had anorexia nervosa of the bulimic subtype.     

Ghrelin: A Link between Eating Disorders,Obesity and Reproduction

Abstract

Ghrelin, a 28-amino acid acylated peptide predominantly produced by the stomach, displays strong GH-releasing activity mediated by the hypothalamic-pituitary GH secretagogues (GHS) receptors (GHS-R) which had been shown specific for a family of synthetic, orally active molecules known as GHS. However, ghrelin and GHS, acting on central and peripheral receptors, also exert other actions. These include influence on pituitary functions, orexigenic action, influence on exocrine and endocrine gastro-entero-pancreatic functions, cardiovascular and anti-proliferative effects. In particular, the effect of ghrelin in promoting food intake and modulating energy metabolism strongly suggested that ghrelin has a key role in managing the neuroendocrine and metabolic response to starvation and that could be involved in the pathogenesis and/or in the metabolic and neuro-hormonal alterations of obesity and eating disorders. Although specific alterations in ghrelin secretion and/or action in obesity and anorexia nervosa (AN) have already been reported, the possibility that ghrelin analogues acting as agonists or antagonists has clinical perspectives for treatment of eating disorders presently remains a dream.     

Gender Differences in Treatment Outcomes for Eating Disorders: A Case-Matched,Retrospective Pre–Post Comparison

Eating disorders (EDs) are increasingly emerging as a health risk in men, yet men remain underrepresented in ED research, including interventional trials. This underrepresentation of men may have facilitated the development of women-centered ED treatments that result in suboptimal outcomes for men. The present study retrospectively compared pre- vs. post-treatment outcomes between age-, diagnosis-, and length-of-treatment-matched samples of n = 200 men and n = 200 women with Anorexia Nervosa (AN), Bulimia Nervosa (BN), Binge Eating Disorder (BED), or Eating Disorder Not Otherwise Specified (EDNOS), treated in the same setting during the same period, and using the same measurements. Compared to women, men with AN showed marked improvements in weight gains during treatment as well as in ED-specific cognitions and general psychopathology. Likewise, men with BED showed marked weight loss during treatment compared to women with BED; ED-specific cognitions and general psychopathology outcomes were comparable in this case. For BN and EDNOS, weight, ED-specific cognitions, and general psychopathology outcomes remained largely comparable between men and women. Implications for treatments are discussed.     

A Systematic Review and Meta-Analysis Finds Increased Blood Levels of All Forms of Ghrelin in Both Restricting and Binge-Eating/Purging Subtypes of Anorexia Nervosa

Anorexia nervosa (AN) is a severe psychiatric condition associated with high mortality and chronicity. The hunt for state, trait, subtyping, and prognostic biomarkers is ongoing and the orexigenic hormone ghrelin and its different forms, acyl ghrelin and desacyl ghrelin, have been proposed to be increased in AN, especially in the restrictive subtype. A systematic literature search was performed using established databases up to 30 November 2020. Forty-nine studies met inclusion criteria for cross-sectional and longitudinal meta-analyses on total ghrelin, acyl ghrelin, and desacyl ghrelin. All forms of ghrelin were increased in the acute stage of anorexia nervosa during fasting compared to healthy controls. Previous notions on differences in ghrelin levels between AN subtypes were not supported by current data. In addition, a significant decrease in total ghrelin was observed pre-treatment to follow-up. However, total ghrelin levels at follow-up were still marginally elevated compared to healthy controls, whereas for acyl ghrelin, no overall effect of treatment was observed. Due to heterogeneity in follow-up designs and only few data on long-term recovered patients, longitudinal results should be interpreted with caution. While the first steps towards a biomarker in acute AN have been completed, the value of ghrelin as a potential indicator of treatment success or recovery status or its use in subtype differentiation are yet to be established.     

Stigmatization toward People with Anorexia Nervosa,Bulimia Nervosa,and Binge Eating Disorder: A Scoping Review

Research about stigmatization in eating disorders (EDs) has highlighted stereotypes, prejudices, and discrimination against people with EDs, as well as their harmful effects on them, including self-stigma and a difficult recovery process. Whereas a recent review focused on the consequences of ED stigma, our work aimed to provide a broader synthesis of ED stigma, including its consequences, but also its content and distribution. More precisely, we focused on three EDs—namely, anorexia nervosa, bulimia nervosa, and binge eating disorder. Based on a systematic search of four major databases in psychology, the present scoping review includes 46 studies published between 2004 and 2021. We did not conduct any quality assessment of the studies included, because our aim was to provide a wide-ranging overview of these topics instead of an appraisal of evidence answering a precise research question. The review confirmed the existence of a common ED stigma: all individuals affected by EDs reviewed here were perceived as responsible for their situation, and elicited negative emotions and social distance. However, our review also depicted a specific stigma content associated with each ED. In addition, the demographic characteristics of the stigmatizing individuals had a notable influence on the extent of ED stigma: men, young adults, and low-income individuals appeared to be the most stigmatizing toward individuals with EDs. It is important to note that ED stigma had a negative effect on individuals’ eating disorders, psychological wellbeing, and treatment-seeking behavior. There is an urgent need for further research on the adverse effects of ED stigma and its prevention.     

Relationship between Negative Running Addiction and Eating Disorder Patterns in Runners

Current studies show an increase in the risk of eating disorders in runners. Since it is known that abusive exercise can be both a cause and a consequence of such developments, the main objective of the present study was to examine the risk and possible relationships between negative running addiction (NRA), as measured by the reduced and validated SAS-40 scale, and the tendency to be a compulsive eater (measured by YFAS 2.0), anorexia nervosa (AN), and/or bulimia nervosa (BN) (measured by EAT-40). This study highlights the novelty of researching the level of influence of NRA on each defined eating disorder. Method: A total of 167 Spanish-speaking federated runners in cross-country and track running (42% women and 58% men), with an average age of 24 years and an average BMI of 21 kg/m², responded to an online questionnaire that asked about sociodemographic data and the Spanish versions of the SAS-40, YFAS 2, YFAS 3, and YFAS 4. Through a quantitative methodology using logistic regressions—the coefficient of determination and Pearson’s correlation coefficient—we created a sample analysis that related the significant items of the DSM-V to the results of the questionnaires administered, as well as their relationship with the practice of the sport in question and various variables of the environment. Results: The rates of CE, AN, and BN were 65, 11.4, and 16.2%, respectively. The tendency towards CE increased with a lower weight (r = 0.156, p < 0.05), not having been overweight in childhood (r = 0.151, p < 0.05), and being a long-distance runner (r = 0.123 p < 0.05). The risk of AN increased with the absence of menstruation for more than 3 months (r = 0.271 p < 0.01), having suffered from childhood obesity (r = 0.213 p < 0.05), and being underweight (r = 0.064 p < 0.05). The risk of BN increased with having suffered from childhood obesity (r = 0.194 p < 0.05), having a higher weight (r = 0.140, p < 0.05), and practicing athletics, especially the relay modality (r = 0.044 p < 0.05). Conclusions: A considerable number of runners are at risk of suffering from some type of eating disorder. A significant relationship was observed between long-distance runners and the risk of eating disorders (AN, BN, and CE), and the association is stronger for CE than for AN and BN. Lastly, childhood experiences (such as being obese/a healthy weight) were notorious for increasing the risk of eating disorders. Further studies are needed to research each particular parameter and the relationships between the possible levels of dependence on exercise. Level of evidence: Level III, cohort analytic study.     

Eating Disorders,Physical Fitness and Sport Performance: A Systematic Review

Background: Eating disorders are health problems that are particularly prevalent in adolescents and young adults. They are associated with considerable physical health and psychosocial morbidity, and increased risk of mortality. We set out to conduct a systematic review to determine their effect on physical fitness in the general population and on sport performance in athletes. Methods/Design: A systematic review of the relevant peer-reviewed literature was performed. For inclusion, articles retrieved from PubMed had to be published in English between 1977 and 2013. Wherever possible, methods and reporting adhere to the guidelines outlined in the PRISMA statement. Some additional studies were retrieved from among those cited in the reference lists of included studies and from non-electronic databases. Literature searches, study selection, method and quality appraisal were performed independently by two authors, and data was synthesized using a narrative approach. Results: Of the 1183 articles retrieved, twenty-nine studies met the inclusion criteria and were consequently analysed. The available data indicate that eating disorders have a negative effect on physical fitness and sport performance by causing low energy availability, excessive loss of fat and lean mass, dehydration, and electrolyte disturbance. Discussion: Although the paucity of the available data mean that findings to date should be interpreted with caution, the information collated in this review has several practical implications. First, eating disorders have a negative effect on both physical fitness and sport performance. Second athletics coaches should be targeted for education about the risk factors of eating disorders, as deterioration in sport performance in athletes, particularly if they are underweight or show other signs of an eating disorder, may indicate the need for medical intervention. However, future studies are needed, especially to assess the direct effect of eating disorders on sport performance.