An interventional study of Prebiotic and L-Tryptophan in Stress, Psychological, sponsored by KU Leuven. Recruiting at 1 site in Belgium. Open to participants aged 18 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2023-10-18.
Sponsored by KU Leuven · Not applicable, Interventional, and Basic science
The interaction between the gut microbiome, the intestinal barrier, and the host plays an important role in human health. The integrity of the intestinal barrier is essential to protect against translocation of food antigens and immunostimulatory microbial metabolites from the gut lumen. Accumulating studies show that stress may negatively affect the intestinal barrier function. In a previous study, the investigators developed the Leuven Prolonged Acute Stress Test (L-PAST), which combines physical (cold water), mental (arithmetic), and social (negative feedback) aspects of stress for a prolonged (2h) time. In the current study the investigators would like, as a first aim, to investigate whether the L-PAST 1) increases intestinal permeability compared to baseline intestinal permeability, and 2) whether a nutritional intervention can improve baseline intestinal permeability as well as intestinal permeability after exposure to the L-PAST in both healthy females and men. As a second aim of the present study, the investigators would like to investigate whether prebiotics and/or L-tryptophan can attenuate the cortisol response to stress. Lastly, as acute psychosocial stress impairs cognitive functions, the investigators would like as a third aim to investigate whether prebiotics and/or L-tryptophan supplementation may prevent these impairments.
783 studies on the registry are indexed under Stress, Psychological; 128 are open to participants now.
This study's planned enrollment of 48 is below the median of 85 across 632 interventional studies indexed under Stress, Psychological.
Browse Stress, Psychological studies →KU Leuven is the lead sponsor of 358 studies on the registry; 62 are open to participants now.
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Exclusion Criteria:
Dietary Supplement: Prebiotic
Dietary Supplement: L-Tryptophan
Dietary Supplement: Placebo
Group 1 (prebiotic and placebo L-tryptophan): prebiotic (oligofructose, Orafti®P95, 20g/day) and placebo L-tryptophan (microcrystalline cellulose, 3g/day)
Group 2 (placebo prebiotic and L-tryptophan): L-tryptophan (3g/day) and placebo prebiotic (microcrystalline cellulose, 20g/day)
Group 3 (placebo prebiotic and placebo L-tryptophan): placebo prebiotic (microcrystalline cellulose, 20g/day) and placebo L-tryptophan (microcrystalline cellulose, 3g/day).
Executive functions during a prolonged stress task (the Leuven Prolonged Stress Test)
Working memory, cognitive flexibility, and response inhibition. Working memory will be assessed using the forward digit span. Cognitive flexibility will be assessed using the Wisconsin Card Sorting Test. Response inhibition will be assessed using the Stop Signal Task.
Time frame: Measured during the stress induction task during both the pre-intervention visit and immediately after the 4 week intervention.
Intestinal permeability after a prolonged stress task (the Leuven Prolonged Stress Test)
Intestinal permeability will be measured using the lactulose-mannitol test. The lactulose-mannitol ratio will be calculated and used as a measure for small intestinal permeability. Fractional excretion of lactulose and mannitol will also be assessed.
Time frame: Measured at the pre-intervention and immediately after the 4 week intervention.
Stress response to a prolonged stress test (the Leuven Prolonged Stress Test)
Cortisol, blood pressure, and subjective stress. Cortisol will be measured in saliva. Subjective stress will be measured using a Visual Analogue Scale (VAS)
Time frame: During the stress task (at multiple time points during 120 min), measured at the pre-intervention and immediately after the 4 week intervention.
Intestinal permeability baseline
Intestinal permeability will be measured using the lactulose-mannitol test. The lactulose-mannitol ratio will be calculated and used as a measure for small intestinal permeability. Fractional excretion of lactulose and mannitol will also be assessed.
Time frame: Measured 2 days before the pre-intervention and immediately after the 4 week intervention.
Short chain fatty acids
Short chain fatty acids will be measured both in feces and serum.
Time frame: Measured for 3h during the pre-intervention and immediately after the 4 week intervention.
Tryptophan metabolites
Tryptophan metabolites (kynurenine and indole pathway) will be measured in urine and blood.
Time frame: Measured in blood for 3h during the pre-intervention and immediately after the 4 week intervention. Urine will be collected 3 days prior to the pre-intervention and immediately after the 4 week intervention.
Inflammatory cytokines
Including interleukin (IL)-1β, IL-6, IL-10, IL-13, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α
Time frame: Measured at the pre-intervention and immediately after the 4 week intervention.
Subjective pain response to the prolonged stress test
The subjective pain response to the prolonged stress task (Leuven Prolonged Stress Test) will be measured using a Visual Analogue Scale (VAS) (1-100)
Time frame: Measured during the stress induction task during both the pre-intervention visit and immediately after the 4 week intervention.
Cognitive reactivity to failure response to the prolonged stress test
Cognitive reactivity to failure response to the prolonged stress task (Leuven Prolonged Stress Test) will be assessed using two rating scales on a scale of 0 to 100. On one scale, 0 means 'I feel much less self-assured than before, 50 means 'I feel as self-assured as before, and 100 means 'I feel much more self-assured than before'. On the other scale, 0 means 'I think I'm not good at anything at all, 50 means 'I still think the same about myself', and 100 means 'I think I can achieve anything'.
Time frame: Measured during the stress induction task during both the pre-intervention visit and immediately after the 4 week intervention.
Perceived Stress Scale (PSS)
The Perceived Stress Scale (PSS) is a 14-item instrument designed to measure the degree to which situations in one's life are appraised as stressful. It provides a tool for examining issues about the role of appraised stress levels in the etiology of disease and behavioral disorders. The scale is designed such that it asks the respondent to rate the frequency of his/her feelings and thoughts related to events and situations that occurred over a selected time-frame. Notably, high PSS scores have been correlated with higher biomarkers of stress, such as cortisol.
Time frame: Measured at the pre-intervention and immediately after the 4 week intervention.
Gastrointestinal symptom rating scale (GSRS)
The Gastrointestinal Symptom Rating Scale (GSRS) is a disease-specific instrument of 15 items combined into five symptom clusters depicting Reflux, Abdominal pain, Indigestion, Diarrhea and Constipation. The GSRS has a seven-point graded Likert-type scale where 1 represents absence of troublesome symptoms and 7 represents very troublesome symptoms. The reliability and validity of the GSRS are well-documented, and norm values for a general population are available.
Time frame: Measured at the pre-intervention and immediately after the 4 week intervention.
Patient Health Questionnaire 9 (PHQ-9)
The Patient Health Questionnaire - 9 (PHQ-9) is a 9-item questionnaire based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). This self-report measure determines the severity of depression symptoms and is frequently used to monitor changes in symptom severity over time in non-psychiatric settings. Subjects are asked to rate each of the items on a scale of 0 to 3 on the basis of how much a symptom has bothered them over the last 2 weeks (0=not at all, 1=several days, 2=more than half the days, and 3=nearly every day).
Time frame: Measured at the pre-intervention and immediately after the 4 week intervention.
Generalized Anxiety Questionnaire 7 (GAD-7)
The Generalized Anxiety Questionnaire (GAD-7) is a 7-item questionnaire based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). This self-report measure reflects the frequency of anxiety symptoms over the past 2 weeks. Subjects are asked to rate each of the items on a scale of 0 to 3 on the basis of how much a symptom has bothered them over the last 2 weeks (0=not at all, 1=several days, 2=more than half the days, and 3=nearly every day).
Time frame: Measured at the pre-intervention and immediately after the 4 week intervention.
Plan to share: Undecided
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