Media exposure and associated stress contribute to eating pathology in women with Anorexia Nervosa: Daily and momentary associations

The role of short-chain fatty acids (SCFAs) in regulating stress responses, eating behavior, and nutritional state in anorexia nervosa: protocol for a randomized controlled trial

OBJECTIVE

This protocol proposes investigating the effects of short-chain fatty acids (SCFAs)-namely acetate, propionate, and butyrate-as mediators of microbiota-gut-brain interactions on the acute stress response, eating behavior, and nutritional state in malnourished patients with anorexia nervosa (AN). SCFAs are produced by bacterial fermentation of dietary fiber in the gut and have recently been proposed as crucial mediators of the gut microbiota's effects on the host. Emerging evidence suggests that SCFAs impact human psychobiology through endocrine, neural, and immune pathways and may regulate stress responses and eating behavior.

METHOD

We will conduct a randomized, triple-blind, placebo-controlled trial in 92 patients with AN. Patients will receive either a placebo or a mixture of SCFAs (acetate propionate, butyrate) using pH-dependent colon-delivery capsules for six weeks. This clinical trial is an add-on to the standard inpatient psychotherapeutic program focusing on nutritional rehabilitation.

HYPOTHESES

We hypothesize that colonic SCFAs delivery will modulate neuroendocrine, cardiovascular, and subjective responses to an acute laboratory psychosocial stress task. As secondary outcome measures, we will assess alterations in restrictive eating behavior and nutritional status, as reflected by changes in body mass index. Additionally, we will explore changes in microbiota composition, gastrointestinal symptoms, eating disorder psychopathology, and related comorbidities.

DISCUSSION

The findings of this study would enhance our understanding of how gut microbiota-affiliated metabolites, particularly SCFAs, impact the stress response and eating behavior of individuals with AN. It has the potential to provide essential insights into the complex interplay between the gut, stress system, and eating behavior and facilitate new therapeutic targets for stress-related psychiatric disorders. This protocol is prospectively registered with ClinicalTrials.gov, with trial registration number NCT06064201.

The psychometric properties of the grazing questionnaire in an obesity sample with and without binge eating disorder

BACKGROUND

Despite being the first validated measure of grazing, the Grazing Questionnaire (GQ) has not been investigated among individuals with obesity. Therefore, the current study aimed to examine the psychometric properties of the GQ in an obesity sample.

METHODS

Participants (N = 259) were recruited from community and clinical settings in Australia. The sample comprised adults with normal weight (n = 77) and obesity (n = 182). A portion of individuals with obesity (n = 102) had binge eating disorder (BED). Data from the obesity group was examined to establish the factor structure, validity, and reliability of the GQ. A one-way ANOVA with planned contrasts was conducted to compare scores on the GQ across groups.

RESULTS

Confirmatory factor analysis revealed that the 2-factor model of the GQ was the best model fit for individuals with obesity. The GQ demonstrated high internal consistency, test-retest reliability over 3 months, and convergent and divergent validity. As hypothesised, the obesity group had significantly higher scores on the GQ than the normal weight group, while the obesity with BED group had significantly higher scores than the obesity without BED group.

CONCLUSION

This was the first study to investigate the psychometric properties of the GQ in an obesity sample. Overall, findings indicated that the GQ is a psychometrically sound measure of grazing among individuals with obesity. These findings provide further support for two distinct subtypes of grazing and highlight the importance of increased assessment and management of grazing behaviours for individuals with obesity and eating disorders. Maintaining a healthy weight is one of the greatest challenges for individuals with obesity. Certain eating patterns such as grazing may contribute to difficulties in weight management. Grazing is the repetitive and unplanned eating of small amounts of food that is not related to feeling hungry. Researchers and clinicians often use self-report questionnaires to measure grazing. However, the first validated questionnaire of grazing has not been investigated among individuals with obesity. Therefore, the goal of this study was to examine and validate the Grazing Questionnaire in individuals with obesity. Overall, our results showed that the Grazing Questionnaire is a valid and reliable self-report measure of grazing in individuals with obesity. Similar to previous research, we found that there are two subtypes of grazing. The first subtype involves continuous, unplanned eating. The second subtype is associated with a sense of loss of control over eating. We also found that people with obesity and binge eating disorder graze more than people with obesity that do not have binge eating disorder, while both groups graze more than individuals with normal weight. We recommend that clinicians routinely assess and treat unhelpful grazing patterns when working with individuals with obesity and eating disorders.

The effects of fitspiration images on body attributes, mood and eating behaviors: An experimental Ecological Momentary Assessment study in females

Through an experimental Ecological Momentary Assessment (EMA) design, we assessed the effects of fitspiration images (relative to neutral) on body image, mood and disordered eating and whether trait body dissatisfaction, thin-ideal internalization and pressures from the media, family and peers moderated these effects. After completing trait-based measures, 85 women were prompted via a mobile application 6 times daily for 7 days to view an image (fitspiration or neutral) and report on state levels of perceived pressures to attain an idealized physique, satisfaction with various body attributes, mood and eating behavior. When participants were exposed to fitspiration images, their perceived pressure to attain an idealized physique was significantly higher than after exposure to the control images. This effect was most pronounced for women experiencing pressure from the media. Furthermore, fitspiration images lowered the extent to which women felt that idealized physiques were attainable, and decreased satisfaction with current fitness. There were no significant effects on mood and disordered eating. Exposure to fitspiration content predicted only a few adverse outcomes in terms of negative body attributes and perceived pressures to attain a similar physique, suggesting that its content is not as detrimental as initially believed, but further research is needed.

Sex differences in stress reactivity in arousal and attention systems

Women are more likely than men to suffer from psychiatric disorders with hyperarousal symptoms, including posttraumatic stress disorder (PTSD) and major depression. In contrast, women are less likely than men to be diagnosed with schizophrenia and attention deficit hyperactivity disorder (ADHD), which share attentional impairments as a feature. Stressful events exacerbate symptoms of the aforementioned disorders. Thus, researchers are examining whether sex differences in stress responses bias women and men towards different psychopathology. Here we review the preclinical literature suggesting that, compared to males, females are more vulnerable to stress-induced hyperarousal, while they are more resilient to stress-induced attention deficits. Specifically described are sex differences in receptors for the stress neuropeptide, corticotropin-releasing factor (CRF), that render the locus coeruleus arousal system of females more vulnerable to stress and less adaptable to CRF hypersecretion, a condition found in patients with PTSD and depression. Studies on the protective effects of ovarian hormones against CRF-induced deficits in sustained attention are also detailed. Importantly, we highlight how comparing males and females in preclinical studies can lead to the development of novel therapeutics to improve treatments for psychiatric disorders in both women and men.

Examining a momentary mediation model of appearance-related stress, anxiety, and eating disorder behaviors in adult anorexia nervosa

PURPOSE

Appearance-related stress may result from appearance-focused events such as seeing one's reflection, seeing media images, and shopping for clothes. The purpose of this study was to examine the prospective association between momentary appearance-related stress and eating disorder (ED) behaviors (i.e., binge eating and vomiting) among women with anorexia nervosa (AN) using ecological momentary assessment (EMA). We hypothesized that appearance-related stress at Time 1 would predict binge eating and vomiting at Time 2, and that this prospective association would be mediated by momentary anxiety at Time 2 (controlling for anxiety at Time 1).

METHODS

Women with AN completed a 2-week EMA protocol involving repeated daily assessments of experiences and behaviors.

RESULTS

Momentary appearance-related stress preceded binge eating and vomiting, and momentary anxiety mediated the prospective association between appearance-related stress and ED behaviors.

CONCLUSIONS

Targeted momentary interventions delivered in the natural environment that address appearance-related stress may have utility in the treatment of ED behaviors.