Executive FunctionGUTSIENCT06286943
The Effects of Short-Chain Fatty Acids in Psychosocial Stress-Induced Impairment on Core Executive Functions
A study testing Short Chain Fatty Acids (SCFAs). and Maastricht Acute Stress Task in people with Executive Function, run by Universitaire Ziekenhuizen KU Leuven at 1 site in Belgium.
Trial summary
The aim of the present trial is to examine core executive functions (EFs) as a functional outcome of attenuating the cortisol response to acute laboratory stress through colonic delivery of an Short Chain Fatty Acids (SCFAs) mix (acetate, propionate, butyrate). Read more about this study
- Who is it for?
- Ages 20 to 40 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Executive Function
- What is being tested?
- Short Chain Fatty Acids (SCFAs). and Maastricht Acute Stress Task
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 80 participants
- Where
- 1 siteBelgium
- Study dates
- 13 Nov 2024to 10 Aug 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 40 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Voluntary written informed consent of the participant or their legally authorized representative has been obtained prior to any screening procedures
- Proficiency in English and/or Dutch
- Healthy with no intestinal and/or psychological complaints
- Access to a -18°C freezer (i.e. ordinary household freezer)
- Male participants
- Age 20-40 years
- BMI 18.5-25 kg/m2
Who cannot join
- Participant has a history of previous or current neurological, psychiatric, gastrointestinal or endocrine disorder
- Any disorder, which in the Investigator's opinion might jeopardise the participant's safety or compliance with the protocol
- Any prior or concomitant treatment(s) that might jeopardise the participant's safety or that would compromise the integrity of the study
- Participation in an interventional Trial with an investigational medicinal product (IMP) or device
- Current or recent (over the past month) medication use as a (prescribed) medical treatment. This does not include isolated intakes of 'over the counter' medication (e.g. ibuprofen, paracetamol).
- Use of antibiotics within three months preceding the study.
Show all 16Show fewer
- Current or recent (1-month) infection (e.g. common cold, influenza, COVID-19, etc.)
- Recent (1-month) vaccination (e.g. flu shot, SARS-COV-2 vaccine, etc)
- Previous or current substance/alcohol dependence or abuse (>2 units per day or 14 units per week).
- One or more diagnoses based on the Mini International Neuropsychiatric Interview.
- One or more diagnoses based on ROME-IV for gastrointestinal disorders.
- Smoking.
- Night-shift work.
- Adherence to special diets (e.g. vegan, vegetarian, weight-loss, lactose-free, gluten-free, etc.).
- Use of pre- or probiotics within one month preceding the study.
- Previous experience with or knowledge of any of the tasks used in the study (not including questionnaires).
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Effects of Gut Bacterial Metabolites Short-Chain Fatty Acids on Stress-Induced Impairment in Core Executive Functions
The aim of the present trial is to examine core executive functions (EFs) as a functional outcome of attenuating the cortisol response to acute laboratory stress through colonic delivery of an Short Chain Fatty Acids (SCFAs) mix (acetate, propionate, butyrate).
A triple-blind randomized placebo-controlled parallel group trial will be conducted to compare the effects of SCFAs vs. placebo on core EFs (working memory [WM], cognitive flexibility [CF], response inhibition [RI]) under stress vs. no-stress conditions, after one week of SCFA vs. placebo treatment.
Read more
First, the effects of SCFAs on stress-induced changes in core executive functions, with WM as the primary outcome, and CF and RI as secondary outcomes will be tested. Second, interindividual differences in microbiota composition (particularly abundance of SCFA-producers), saliva cortisol and serum SCFA levels will be explored to assess whether they are associated with interindividual differences in core EFs at baseline or following acute stress.
Each participant will undergo 2 study visits: one will involve a stress condition and the other will involve a no-stress condition. Each study visit is preceded by a 1-week intervention or placebo period and separated by a 3-4 week washout period. To induce stress, participants will perform the Maastricht Acute Stress Task (MAST) or sham MAST as the control condition. To assess EF performance, three cognitive tasks will be performed 15 minutes after task offset: n-back task for WM; Stop Signal Task for RI; and Wisconsin Card Sorting Test for CF. Saliva samples will be collected before, during and after the (sham) MAST to assess the cortisol response. Blood samples will be collected throughout all study visits to quantify serum SCFAs, inflammatory markers and ACTH. Additionally, cardiovascular variables will be measured, and self-report questionnaires will be completed to evaluate autonomic response to the condition and subjective stress responses, respectively
- Conditions
- Executive Function
- Being tested
- Short Chain Fatty Acids (SCFAs)., Placebo, Maastricht Acute Stress Task, No-stress control task
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Short Chain Fatty Acids (SCFAs).Dietary supplement
Colon-delivery capsules of SCFAs.
PlaceboDietary supplement
Microcrystaline cellulose placebo capsules.
Maastricht Acute Stress TaskOther
Also called MAST, cold, arithmetics
The Maastricht Acute Stress Task. This 15-minute stress-inducing task consists of a 5-minute preparation phase where instructions about the upcoming tasks are given, followed by a 10-minute acute stress phase where the hand immersion trial (HIT) in ice-cold water and mental arithmetic (MA) task is given interchangeably.
No-stress control taskOther
Also called Sham MAST
The placebo version of the MAST follows the same structure of the MAST with none of the stress elements. It uses lukewarm water and simple arithmetic's.
| Study group | Role | What they receive |
|---|---|---|
| Placebo | Placebo comparator | Microcrystalline cellulose placebo capsules. Receives: Dietary Supplement: Placebo; Other: Maastricht Acute Stress Task; Other: No-stress control task |
| SCFAs | Experimental | Colon-delivery Capsules of Short Chain Fatty Acids. Receives: Dietary Supplement: Short Chain Fatty Acids (SCFAs).; Other: Maastricht Acute Stress Task; Other: No-stress control task |
What is being measured
The primary outcome is the main question the study is designed to answer.
Working memory
n-Back task
Measured: Test day 1 and Test day 2 (Stress vs. No-stress conditions)
Secondary outcomes (2)
Cognitive Flexibility
Wisconsin Card Sorting Task
Measured: Test day 1 and Test day 2 (Stress vs. No-stress conditions)
Response Inhibition
Stop Signal Task
Measured: Test day 1 and Test day 2 (Stress vs. No-stress conditions)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Feb 2024
- Study start13 Nov 2024
- Primary completion10 Aug 2026
- Study completion10 Aug 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Executive FunctionStudies of the same condition, open and under way.
- More trials run by Universitaire Ziekenhuizen KU LeuvenThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 80 participants (actual)
Sponsor and investigators
- Lead sponsor
- Universitaire Ziekenhuizen KU Leuven
- Sponsor type
- University, hospital or other
- Collaborators
- United States Department of Defense
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06286943
- Sponsor's protocol ID
- S68124
- Acronym
- GUTSIE
- Status last verified
- Apr 2026
- First submitted
- 16 Feb 2024
- Last updated
- 26 Oct 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 26 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effects of Gut Bacterial Metabolites Short-Chain Fatty Acids on Stress-Induced Impairment in Core Executive Functions
- ClinicalTrials.gov ID
- NCT06286943
- Acronym / sponsor ID
- GUTSIE / S68124
- Conditions
- Executive Function
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 80 participants (actual)
- Lead sponsor
- Universitaire Ziekenhuizen KU LeuvenUniversity, hospital or other
- Collaborators
- United States Department of Defense
- Study start
- 13 Nov 2024 (actual)
- Primary completion
- 10 Aug 2026 (actual)
- Study completion
- 10 Aug 2026 (actual)
- First posted
- 29 Feb 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of the present trial is to examine core executive functions (EFs) as a functional outcome of attenuating the cortisol response to acute laboratory stress through colonic delivery of an Short Chain Fatty Acids (SCFAs) mix (acetate, propionate, butyrate).
A triple-blind randomized placebo-controlled parallel group trial will be conducted to compare the effects of SCFAs vs. placebo on core EFs (working memory [WM], cognitive flexibility [CF], response inhibition [RI]) under stress vs. no-stress conditions, after one week of SCFA vs. placebo treatment.
First, the effects of SCFAs on stress-induced changes in core executive functions, with WM as the primary outcome, and CF and RI as secondary outcomes will be tested. Second, interindividual differences in microbiota composition (particularly abundance of SCFA-producers), saliva cortisol and serum SCFA levels will be explored to assess whether they are associated with interindividual differences in core EFs at baseline or following acute stress.
Each participant will undergo 2 study visits: one will involve a stress condition and the other will involve a no-stress condition. Each study visit is preceded by a 1-week intervention or placebo period and separated by a 3-4 week washout period. To induce stress, participants will perform the Maastricht Acute Stress Task (MAST) or sham MAST as the control condition. To assess EF performance, three cognitive tasks will be performed 15 minutes after task offset: n-back task for WM; Stop Signal Task for RI; and Wisconsin Card Sorting Test for CF. Saliva samples will be collected before, during and after the (sham) MAST to assess the cortisol response. Blood samples will be collected throughout all study visits to quantify serum SCFAs, inflammatory markers and ACTH. Additionally, cardiovascular variables will be measured, and self-report questionnaires will be completed to evaluate autonomic response to the condition and subjective stress responses, respectively
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Placebo | Placebo comparator | Dietary Supplement: Placebo, Other: Maastricht Acute Stress Task, Other: No-stress control taskMicrocrystalline cellulose placebo capsules. |
| SCFAs | Experimental | Dietary Supplement: Short Chain Fatty Acids (SCFAs)., Other: Maastricht Acute Stress Task, Other: No-stress control taskColon-delivery Capsules of Short Chain Fatty Acids. |
Who may qualify
- Ages
- 20 to 40 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- Voluntary written informed consent of the participant or their legally authorized representative has been obtained prior to any screening procedures
- Proficiency in English and/or Dutch
- Healthy with no intestinal and/or psychological complaints
- Access to a -18°C freezer (i.e. ordinary household freezer)
- Male participants
Key exclusion criteria (16 listed)
- Participant has a history of previous or current neurological, psychiatric, gastrointestinal or endocrine disorder
- Any disorder, which in the Investigator's opinion might jeopardise the participant's safety or compliance with the protocol
- Any prior or concomitant treatment(s) that might jeopardise the participant's safety or that would compromise the integrity of the study
- Participation in an interventional Trial with an investigational medicinal product (IMP) or device
- Current or recent (over the past month) medication use as a (prescribed) medical treatment. This does not include isolated intakes of 'over the counter' medication (e.g. ibuprofen, paracetamol).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Short Chain Fatty Acids (SCFAs).Colon-delivery capsules of SCFAs. | Dietary supplement | SCFAs |
| PlaceboMicrocrystaline cellulose placebo capsules. | Dietary supplement | Placebo |
| Maastricht Acute Stress TaskAlso: MAST, cold, arithmeticsThe Maastricht Acute Stress Task. This 15-minute stress-inducing task consists of a 5-minute preparation phase where instructions about the upcoming tasks are given, followed by a 10-minute acute stress phase where the hand immersion trial (HIT) in ice-cold water and mental arithmetic (MA) task is given interchangeably. | Other | Placebo, SCFAs |
| No-stress control taskAlso: Sham MASTThe placebo version of the MAST follows the same structure of the MAST with none of the stress elements. It uses lukewarm water and simple arithmetic's. | Other | Placebo, SCFAs |
Primary outcome
Working memory
Time frame: Test day 1 and Test day 2 (Stress vs. No-stress conditions)
n-Back task
2 secondary outcomes
Cognitive Flexibility
Time frame: Test day 1 and Test day 2 (Stress vs. No-stress conditions)
Response Inhibition
Time frame: Test day 1 and Test day 2 (Stress vs. No-stress conditions)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Oct 2026.
Related trials for Executive Function
Not yet recruiting
Cognitive-Motor Training With the DextEgg in Children With ADHD
Attention Deficit Hyperactivity Disorder (ADHD)
Recruiting
Virtual Reality in Rehabilitation of Executive Functions in Children With Mild or Moderate Traumatic Brain Injury
Traumatic Brain Injury
Recruiting
Neocortical Microarchitecture of Executive Function
Parkinson Disease
Active, not recruiting
Learning by Heart: The Effectiveness of an EF Training Program for Pre-schoolers With Critical CHD
Congenital Heart Disease, Executive Dysfunction
Recruiting
Acupuncture for ADHD: Acupoint Data Mining, Clinical Effectiveness, and Interviews to Explore Treatment Outcomes.
Acupuncture, ADHD - Attention Deficit Disorder With Hyperactivity
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Short Chain Fatty Acids (SCFAs). and Maastricht Acute Stress Task in people with Executive Function, run by Universitaire Ziekenhuizen KU Leuven at 1 site in Belgium.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 26 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Working memory (time frame: Test day 1 and Test day 2 (Stress vs. No-stress conditions)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Oct 2026.