A Nutritional Intervention to Prevent Stress Induced Intestinal Hyper-Permeability (HYPERNUTRI)

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.

Study Overview

• Status: Recruiting
• Conditions: Stress, Psychological
• Intervention / Treatment: Dietary supplement: Prebiotic; Dietary supplement: L-Tryptophan; Dietary supplement: Placebo

• Study Type: Interventional
• Enrollment (Estimated): 48
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Danique La Torre, MSc; Phone Number: +3216373499; Email: danique.latorre@kuleuven.be
• Study Contact Backup: Name: Kristin Verbeke, PhD; Phone Number: +3216330150; Email: kristin.verbeke@kuleuven.be

Study Locations

• Belgium
  • Vlaams-Brabant
    • Leuven, Vlaams-Brabant, Belgium, 3000
      • Recruiting
      • KU Leuven/ UZ Leuven
      • Principal Investigator: Kristin Verbeke, PhD
      • Contact: Danique La Torre, MSc; Phone Number: +3216373499; Email: danique.latorre@kuleuven.be
      • Contact: Kristin Verbeke, PhD; Phone Number: +3216330150; Email: kristin.verbeke@kuleuven.be
      • Sub-Investigator: Lukas Van Oudenhove, PhD, MD
      • Sub-Investigator: Tim Vanuytsel, PhD, MD
      • Sub-Investigator: Danique La Torre, MSc

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age 18 till 40 years (both included)
• BMI range: 18.5 - 25 kg/m²
• Females: Use of contraceptives, and have to use the current contraceptive method for at least 4 months. A regular menstrual cycle (between 25 and 35 days; if not using oral contraceptives)
• Subject is willing to not consume caffeine, or alcohol, to refrain from smoking, and not to engage in heavy physical exercise three days before the test days, as well as to not consume dairy products and chewing gum the day before and the day of the test days
• Subject is willing to not take any non-steroidal anti-inflammatory drugs (NSAIDs) two weeks before the test days (see Appendix G for an overview of NSAIDs)
• Subject, upon briefing of the content of the present study, fully understands and agrees to its objective and has given written (dated and signed) informed consent form to take part in the study
• Subject is able to communicate well with the investigator and follow instructions given by the investigator

Exclusion Criteria:

• Subject has a previous or current neurological, psychiatric, gastrointestinal, or endocrine disorder, or other relevant medical history
• Subject has one or more diagnoses based on the MINI international neuropsychiatric interview
• Subject has one or more diagnoses based on the ROME-IV for GI disorders
• Subject uses regular medication (i.e., anti-allergy medication, PPI's, and medication that can affect gut motility), currently or recently (in the last 2 weeks) (except for oral contraceptives)
• Subject has used recreational drugs in the past 6 months
• Subject consumes regularly (>1/week) more than 3 units of alcohol per day
• Subjects smokes >7 cigarettes per week
• Subject has to work in night-shifts
• Subject is pregnant or lactating
• Subject has previous experience with the stress test used in the study
• Subject has taken prebiotics or probiotics in the last month
• Subject has taken antibiotics in the last 3 months
• Subjects consumes >25g of fiber per day in their habitual diet

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo	Dietary supplement: Placebo; Group 3 (placebo prebiotic and placebo L-tryptophan): placebo prebiotic (microcrystalline cellulose, 20g/day) and placebo L-tryptophan (microcrystalline cellulose, 3g/day).
Experimental: Prebiotic	Dietary supplement: Prebiotic; Group 1 (prebiotic and placebo L-tryptophan): prebiotic (oligofructose, Orafti®P95, 20g/day) and placebo L-tryptophan (microcrystalline cellulose, 3g/day)
Experimental: L-Tryptophan	Dietary supplement: L-Tryptophan; Group 2 (placebo prebiotic and L-tryptophan): L-tryptophan (3g/day) and placebo prebiotic (microcrystalline cellulose, 20g/day)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	Measured during the stress induction task during both the pre-intervention visit and immediately after the 4 week intervention.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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)	During the stress task (at multiple time points during 120 min), measured at the pre-intervention and immediately after the 4 week intervention.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	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.	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	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)	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'.	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.	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.	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).	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).	Measured at the pre-intervention and immediately after the 4 week intervention.

Collaborators and Investigators

• Sponsor: KU Leuven

Study record dates

Study Major Dates

• Study Start (Actual): October 10, 2023
• Primary Completion (Estimated): July 1, 2024
• Study Completion (Estimated): July 1, 2024

Study Registration Dates

• First Submitted: October 10, 2023
• First Submitted That Met QC Criteria: October 17, 2023
• First Posted (Actual): October 18, 2023

Study Record Updates

• Last Update Posted (Actual): October 18, 2023
• Last Update Submitted That Met QC Criteria: October 17, 2023
• Last Verified: October 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Behavioral Symptoms; Stress, Psychological; Psychotropic Drugs; Antidepressive Agents; Antidepressive Agents, Second-Generation; Tryptophan
• Other Study ID Numbers: S66915

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No