This clinical trial aims to test the psychobiological effects of certain substances produced by gut bacteria, known as short-chain fatty acids (SCFAs), in people with anorexia nervosa.
Objective This protocol proposes investigating the effects of short-chain fatty acids (SCFAs), produced by gut bacterial fermentation of dietary fiber, 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 have recently been proposed as crucial mediators of the microbiome's effects on the host. Emerging evidence suggests that SCFAs impact human physiology through various physiological pathways and may regulate stress responses and eating behavior. Method The investigators will conduct a randomized, triple-blind, placebo-controlled trial in 92 AN patients. Patients will receive either a placebo or a mixture of SCFAs (acetate propionate, butyrate) using colon-delivery capsules (CDCs) for six weeks. This clinical trial is an add-on to the standard inpatient psychotherapeutic program focusing on nutritional rehabilitation. Hypotheses The investigators hypothesize that colonic SCFAs delivery will modulate neuroendocrine, cardiovascular, and subjective responses to an acute laboratory psychosocial stress task. As secondary outcome measures, the investigators will assess alterations in restrictive eating behavior and nutritional status, as reflected by changes in body mass index (BMI). Additionally, the investigators will explore changes in microbiota composition, gastrointestinal symptoms, eating disorder psychopathology, and related comorbidities. Discussion The findings of this study can enhance our understanding of how gut microbiota-produced 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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
QUADRUPLE
Enrollment
92
The SCFAs mixture contains acetate, butyrate, and propionate in a ratio of 60:20:20, and the total daily amount of SCFAs is equivalent to the fermentation of 10g of arabinoxylan oligosaccharides. Participants will be asked to consume these capsules spread at four intervals throughout the day. The nursing staff will distribute the capsules to the participants individually, supervise their intake, and monitor adherence by capsule count.
To serve as a placebo, microcrystalline cellulose will be included in the same type of CDCs.
UZ/KU Leuven
Leuven, Vlaams Brabant, Belgium
Salivary cortisol response following TSST
Changes in salivary cortisol levels in response to acute laboratory stress (Trier Social Stress Test).
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Restrictive food choices during Food Choice Task
Food choices made under stress are measured through the food choice task, focusing on the proportion of high-fat food items chosen over the reference item.
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Nutritional status (BMI)
Nutritional status of participants determined by calculating Body Mass Index (BMI) from recurrently measured weight
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention) and at the follow-up visit (12 weeks following the start of the intervention)
Neuroendocrine Measures (salivary alpha amylase)
Salivary alpha-amylase (sAA) levels are measured using salivary samples in response to acute laboratory stress (Trier Social Stress Test).
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Neuroendocrine Measures (ACTH)
Adrenocorticotropic hormone (ACTH) serum levels are measured in response to acute laboratory stress (Trier Social Stress Test).
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Subjective stress in relation to TSST
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Participants' subjective subjective stress experience in response to acute laboratory stress is measured using Visual Analog Scales (VAS, scale 0-100), where higher scores indicate higher subjective stress.
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Subjective stress appraisal in relation to TSST
The Primary Appraisal and Secondary Appraisal (PASA) scale assesses various stress-related cognitive processes in anticipation of the TSST. The scale comprises four sub-scales: Threat, Challenge, Outcome Expectancy, and Self-efficacy. The first two address issues related to primary appraisal, and the latter two focus on secondary appraisal. Finally, an overall score for perceived stress can also be calculated from PASA by subtracting the secondary appraisal score from that of primary appraisal. Higher scores reflect a more positive anticipatory cognitive stress appraisal.
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Subjective anxiety in relation to TSST
Participants' subjective experience of anxiety in response to acute laboratory stress is measured using Visual Analog Scales (VAS, scale 0-100). Higher scores indicate a higher subjective anxiety experience.
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Subjective hunger in relation to TSST
Participants' subjective experience of hunger in response to acute laboratory stress is measured using Visual Analog Scales (VAS, scale 0-100). Higher scores indicate higher subjective hunger.
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Subjective appetite in relation to TSST
Participants' subjective experience of appetite in response to acute laboratory stress is measured using Visual Analog Scales (VAS, scale 0-100). Higher scores indicate higher subjective appetite.
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Heart rate response to acute laboratory stress
Physiological measures to acute laboratory stress: measurement of( autonomic nervous system activity) heart rate response (unit: beats per minute) to acute laboratory stress using EmbracePlus wearable wrist device.
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Heart rate variability to acute laboratory stress
Physiological measures to acute laboratory stress: measurement of( autonomic nervous system activity) heart rate variability (unit: milliseconds) to acute laboratory stress using EmbracePlus wearable wrist device.
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Electrodermal activity to acute laboratory stress
Physiological measures to acute laboratory stress: measurement of( autonomic nervous system activity) Electrodermal activity (unit: micro siemens) to acute laboratory stress using EmbracePlus wearable wrist device.
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Self controlled choices during Food Choice Task
The proportion of self-controlled choices, choosing healthy, less tasty foods or not choosing unhealthy, tasty foods during the food choice task
Time frame: Baseline (at hospital admission and before intervention) and post-intervention (following six weeks of intervention)
Eating Disorder Symptoms
The severity of eating disorder symptoms is evaluated using the Eating Disorder Examination Questionnaire (EDE-Q). The EDE-Q is a 28-item self-report questionnaire adapted from the semi-structured interview, the Eating Disorder Examination (EDE). The questionnaire is designed to assess the range, frequency, and severity of behaviors associated with a diagnosis of an eating disorder. Higher scores indicate more problematic eating behaviors and attitudes.
Time frame: Self-reported questionnaires are completed at the baseline visit (at hospital admission and before intervention), three weeks into the intervention, post intervention (following six weeks of intervention) and at the follow-up visit (12 weeks following
Restrained, emotional and external eating behaviour
Restrained, emotional and external eating behaviour is evaluated using the Dutch Eating Behavior Questionnaire (DEBQ). The DEBQ is a 33-item self-report questionnaire to assess three distinct eating behaviors in adults: (1) emotional eating, (2) external eating, and (3) restrained eating. Items on the DEBQ range from 1 (never) to 5 (very often), with higher scores indicating greater endorsement of the eating behavior.
Time frame: Self-reported questionnaires are completed at the baseline visit (at hospital admission and before intervention), three weeks into the intervention, post intervention (following six weeks of intervention) and at the follow-up visit (12 weeks following
Hedonic hunger
Hedonic hunger is evaluated using the Power of Food Scale (PFS). The PFS assesses the psychological impact of living in food-abundant environments. It measures appetite for, rather than consumption of, palatable foods, at three levels of food proximity (food available, food present, and food tasted). The PFS consists of 15 items, rated on a 5-point Likert scale, assessing preoccupation with palatable foods across three distinct but related domains (contributing to three separate subscales of the measure).
Time frame: Self-reported questionnaires are completed at the baseline visit (at hospital admission and before intervention), three weeks into the intervention, post intervention (following six weeks of intervention) and at the follow-up visit (12 weeks following