Subjective Cognitive DeclinePRECODENCT06433037
Gut-brain Health Effects of PREbiotics in Older Adults With Suspected COgnitive DEcline
A study testing Chicory inulin, Resistant dextrin and Seaweed polysaccharide in people with Subjective Cognitive Decline, run by Wageningen University at 1 site in Netherlands.
Trial summary
As people around the world are living longer, the number of individuals with dementia, particularly Alzheimer's disease (AD), is expected to triple by 2050. There's growing evidence suggesting that our gut health might play a role in the prevention of dementia. Read more about this study
- Who is it for?
- Ages 60 to 79 years
- Conditions the study is for
- Subjective Cognitive Decline
- What is being tested?
- Chicory inulin, Resistant dextrin and Seaweed polysaccharide
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 164 participants
- Where
- 1 siteNetherlands
- Study dates
- 16 Jul 2024to Apr 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 60 to 79 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Written informed consent
- Fluency in Dutch (speaking, reading, writing)
- Age between 60-79 years (at screening)
- Subjective cognitive decline plus (SCD+), (criteria of Jessen et al.):
- 4.1 Self-reported worsening of memory; 4.2 Indication of repetitive concerns (worries) associated with SCD; 4.3 With at least one of the following two features present: (i) onset of SCD within the last 5 years; (ii) age at onset ≥60 years of age;
- 5. Presence of at least 2 self-reported risk factors for cognitive decline (based on LIBRA criteria): (i) Diabetes mellitus type II (ii) High cholesterol (iii) Hypertension (iv) High BMI (v) Heart disease (vi) Unhealthy diet (lower regular adherence to Mediterranean diet components such as fish, vegetables, olive oil, pasta and red wine)
Who cannot join
- Current participation in other intervention trials
- Technologically illiterate (complete incompetence in working with computers, apps, online questionnaires, smartwatches etc.)
- No internet access from home
- Clinical diagnosis of ≥1 of the following:
- Neurological pathology (e.g. MCI, dementia, multiple sclerosis, Parkinson's disease, epilepsy);
- Current malignant disease(s), with or without treatment;
Show all 25Show fewer
- Current psychiatric disorder(s) (e.g. major depressive disorder, bipolar disorder, schizophrenia, anxiety, psychosis, PTSD);
- Symptomatic/decompensated cardiovascular disease (e.g. stroke, angina pectoris, heart failure, recent myocardial infarction);
- Severe visual impairment or blindness
- Hearing or communicative impairment.
- Gastrointestinal tract disorder such as irritable bowel syndrome or inflammatory bowel disease (e.g. Crohn's disease or ulcerative colitis).
- Current or recent (<6 weeks) use of prebiotic, probiotic, or dietary fibre supplement that may modulate the microbiota, or unwilling to stop the use of supplements during the study
- Current or recent (<6 weeks) of algae/phytoplankton supplements such as spirulina or chlorella, or unwilling to stop the use of supplements during the study
- Use of psychotropic medication (anti-depressants, anti-psychotics)
- Use of antibiotics in the 3 months before starting the study or planned use during the study
- Being an employee of the Human Nutrition and Health Division of Wageningen University.
- Significant cognitive impairment assessed using the Modified Telephone Interview for Cognitive Status battery (TICS-m score <23)
- Request to have Apo-E genotype result disclosed
- Allergies to fish or shellfish
- Having a contra-indication to MRI scanning including:
- Ferromagnetic implants:
- Active implantable medical devices such as: insulin pump / medicine pump / neurostimulator; pacemaker / defibrillator;
- Other passive implants such as: punctured port-a-cath; synthetic heart valve
- Intra-orbital or intra-ocular metallic fragments
- Claustrophobia
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Gut-brain Health Effects of PREbiotics in Older Adults With Suspected COgnitive DEcline: The PRECODE Study
As people around the world are living longer, the number of individuals with dementia, particularly Alzheimer's disease (AD), is expected to triple by 2050. There's growing evidence suggesting that our gut health might play a role in the prevention of dementia. The connection between our gut and brain, known as the gut-brain axis, is becoming an important area of study. Research in animals has shown that different types of dietary fibre can improve gut health, brain function, mood, blood sugar level and the immune system and may even prevent certain harmful brain changes seen in Alzheimer's disease. Subjective Cognitive Decline (SCD) is a condition where individuals notice a decline in their mental abilities, and it can be an early sign of Alzheimer's disease.
The goal of this clinical trial is to learn if dietary fibres can improve gut and brain health in older individuals, between the ages of 60 and 79 years, who notice problems in their mental abilities, and meet the criteria of SCD. Three different dietary fibres will be given, and researchers will compare three different fibres to a placebo product to see if there is a difference between the fibres and the placebo.
Read more
The main questions it aims to answer are:
- Does dietary fibre improve working memory?
- Does dietary fibre improve other markers of brain function?
- Does dietary fibre improve gut health?
- Does dietary fibre improve the immune system and blood glucose levels?
- Does dietary fibre improve mood?
Participants will:
- Consume dietary fibres twice a day, mixed in water, tea or coffee, for a period of 26 weeks
- Have two functional MRI scans, and three additional study visits, where blood, urine and feces will be collected
- Undergo a number of neuropsychological tests, aimed at evaluating brain function
- Fill out questionnaires on their general health, mood, dietary habits, gut health
- Wear smartwatches for one week, at the beginning and the end of the study
Read the detailed description
Rationale: Due to the greying of society, a triplication of the number of people with dementia worldwide, with Alzheimer's disease (AD) as the commonest form, is expected by 2050. Compelling evidence points towards a crucial role of intestinal health as one potential etiological modifier of dementia, with the (microbiota) gut-brain axis (MGBA) receiving increasing attention. A number of preclinical studies have demonstrated benefit of various sources of dietary fibre for their capacity to improve gut health, cognitive functioning, general mood, glycaemia, immunogenicity, and, to inhibit tau phosphorylation, the latter which is a hallmark in AD brain. Subjective cognitive decline (SCD) lies on the continuum of AD, and subjects with this condition are at increased risk of further conversion to mild cognitive impairment (MCI) or AD. Currently, no cure is available for AD. Various symptomatic and a few disease-modifying treatments are available, but these treatments only have very limited or mild clinical effects and are often accompanied by severe side effects. Clinical follow-up studies to evaluate the effect of dietary fibre in older adults with suspected cognitive decline are required, but are still lacking to date.
Objective: The primary objective of this study is to investigate the effect of 26 weeks of supplementation with three different dietary fibres (chicory inulin, resistant dextrin, and seaweed polysaccharide) compared to a placebo (maltodextrin) on microbiota gut-brain health effects in older adults (aged 60-79) with Subjective Cognitive Decline Plus (SCD+) by assessing changes in brain function and working memory by blood oxygen level dependant (BOLD) signal activity and task accuracy during n-back task functional magnetic resonance imaging (fMRI) assessment.
The secondary objectives are to investigate the effects of 26 weeks of supplementation with dietary fibre (chicory inulin, resistant dextrin, and, seaweed polysaccharide) compared to placebo (maltodextrin) in older adults on the following parameters related to potential gut-brain pathways:
- neuropsychological test battery scoring,
- other relevant brain health parameters,
- relevant intestinal health parameters, and
- immune and metabolic parameters.
Study population: 164 older adults (60-79 years) with SCD+.
Study design implementation:
Participants will undergo assessments at baseline (T0), mid-study (T1/2, after 13 weeks) and at study end (T1, after 26 weeks. Each participant will have five study visits in total: two at T0, one at T1/2 and two at T1.
At each of the timepoints the following will be collected/performed at WUR: Sample collection (blood, urine (omitted in week 13), faeces); general cognitive assessments (see NTB; Cognitive Failure Questionnaire (CFQ) (baseline and end only), GDS-15, GAD-7); general physiological measures (blood pressure, BMI, grip-strength); dietary assessment (MIND-adjusted Eetscore, FFQ). At ZGV working memory will be evaluated using BOLD fMRI signalling and task accuracy using an n-back task paradigm. Additionally, high-resolution T1- and T2-weighted anatomical images of main regions of interest (hippocampi, (pre)frontal-, and temporal cortices) will be acquired.
For two periods of one week, corresponding with the baseline and week 26 visits, participants will wear smartwatches. These watches will be worn continuously and data will be gathered regarding cardiovascular functioning (heart rate), physical activity and mood (push messages).
- Conditions
- Subjective Cognitive Decline
- Being tested
- Chicory inulin, Resistant dextrin, Seaweed polysaccharide, Placebo
- Keywords
- gut-brain axis, working memory, gut health, dietary fibres, prebiotics
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Chicory inulinDietary supplement
Chicory inulin (12g/day) divided over two dosages (6g per dose)
Resistant dextrinDietary supplement
Resistant dextrin (14g/day) divided over two dosages (7g per dose)
Seaweed polysaccharideDietary supplement
Seaweed polysaccharide (1g/day) divided over two dosages (0.5g per dose). Additionally contains 7g/day of placebo as a volumetric and isocaloric filler.
PlaceboDietary supplement
Maltodextrin (7g/day) will be provided in two divided doses (3.5g per dose)
| Study group | Role | What they receive |
|---|---|---|
| Maltodextrin | Placebo comparator | Not described Receives: Dietary Supplement: Placebo |
| Chicory inulin | Experimental | Not described Receives: Dietary Supplement: Chicory inulin |
| Resistant dextrin | Experimental | Not described Receives: Dietary Supplement: Resistant dextrin |
| Seaweed polysaccharide | Experimental | Not described Receives: Dietary Supplement: Seaweed polysaccharide |
What is being measured
The primary outcome is the main question the study is designed to answer.
Effect on working memory during n-back task fMRI
Effects on working memory will be assessed by blood-oxygen level dependant (BOLD) signal activity during 2-back task performed during fMRI scanning
Measured: Measured at baseline and week 26
Effect on working memory performance during n-back task fMRI
Effects on working memory performance will be assessed by task accuracy during 2-back task performed during fMRI scanning
Measured: Measured at baseline and week 26
Secondary outcomes (25)
Effect on cognitive functioning as measured by a neuropsychological test battery
Effect on z-scoring of cognitive domains- episodic memory, executive function and working memory as measured by Cognitive Function Composite test battery
Measured: Measured at baseline, week 13 and week 26
Effect on ADAS-Cog Word Recall cognitive assessment (episodic memory)
Mean number of correct responses across three trials; Score 0 to 10. Higher score indicates better outcome.
Measured: Measured at baseline, week 13 and week 26
Effect on ADAS-Cog Word Recognition cognitive assessment (episodic memory)
Mean number of correct responses across three trials. Score 0 to 12. Higher score indicates better outcome.
Measured: Measured at baseline, week 13 and week 26
Effect on Digit Symbol Substitution Test cognitive assessment (executive function)
Amount of symbols correctly substituted. Score 0 - 90. Higher score indicates better outcome
Measured: Measured at baseline, week 13 and week 26
Effect on Digit Span Backward Task cognitive assessment (working memory)
Longest span of digits correctly recalled. Score 2-8. Higher score indicates better outcome
Measured: Measured at baseline, week 13 and week 26
Effect on Category Fluency Test cognitive assessment (executive function)
Number of uniquely named items from category within 60 seconds. Higher score indicates better outcome
Measured: Measured at baseline, week 13 and week 26
Effect on ADAS-Cog Orientation cognitive assessment (episodic memory)
The number of correct responses on orientation. Score 0 to 8. Higher score indicates better outcome
Measured: Measured at baseline, week 13 and week 26
Effect on tryptophan metabolites
Tryptophan related neurotransmitters and metabolites (plasma)
Measured: Measured at baseline and week 26
Effect on amyloid-beta (Aβ) biomarker
Aβ1-42/Aβ1-40 ratio (plasma)
Measured: Measured at baseline and week 26
Effect on neuroplasticity
Brain-derived neurotrophic factor (BDNF) levels (serum)
Measured: Measured at baseline and week 26
Effect on brain regions of interest
Structural MRI with T1- and T2-weighted anatomical images of regions of interest (hippocampi, (pre)frontal-and temporal cortices)
Measured: Measured at baseline and week 26
Effect on hypothalamic-pituitary adrenal axis
Cortisol levels (serum)
Measured: Measured at baseline and week 26
Effect on intestinal barrier integrity
Assay-based panel of intestinal barrier integrity markers measured in blood
Measured: Measured at baseline, week 13 and week 26
Effect on intestinal inflammation
Assay-based panel of intestinal inflammatory markers measured in faeces
Measured: Measured at baseline, week 13 and week 26
Effect on gastrointestinal transit time
Gut transit time measured by blue muffin consumption and appearance of blue colour in faeces
Measured: Measured at baseline, week 13 and week 26
Effect on gastrointestinal symptoms
Self-rated gastrointestinal symptoms as measured by the Gastrointestinal Symptom Rating Scale (GSRS) questionnaire
Measured: Measured at baseline, week 13 and week 26
Effect on self-reported stool consistency
Effect on stool consistency as measured by Bristol Stool Scale (BSS)
Measured: Measured at baseline, week 13 and week 26
Effect on stool consistency
Effect on stool consistency as measured by faecal water content
Measured: Measured at baseline, week 13 and week 26
Effect on qualitative faecal microbiota composition
Qualitative faecal microbiota composition as measured by 16s rRNA sequencing
Measured: Measured at baseline, week 13 and week 26
Effect on quantitative faecal microbiota composition
Quantitative faecal microbiota composition as measured by digital droplet PCR
Measured: Measured at baseline, week 13 and week 26
Effect on faecal metabolites
Faecal short-chain fatty acids (acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid) and branched-chain fatty acids (isobutyric acid, isovaleric acid, 4-methyl valeric acid) as measured by gas chromatography-flame ionization detection (GC-FID)
Measured: Measured at baseline, week 13 and week 26
Effect on faecal pH
Faecal pH measurement
Measured: Measured at baseline, week 13 and week 26
Effect on immune parameters
Inflammatory cytokine panel measured in blood
Measured: Measured at baseline, week 13 and week 26
Effect on glucose homeostasis
Assay-based panel of markers to evaluate glucose homestasis in blood
Measured: Measured at baseline, week 13 and week 26
Effect on lipid profile
Assay-based panel of markers to analyse lipid profile in blood
Measured: Measured at baseline, week 13 and week 26
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 May 2024
- Study start16 Jul 2024
- Primary completionJan 2026 (estimated)
- Study completionApr 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Subjective Cognitive DeclineStudies of the same condition, open and under way.
- 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Randomised, double-blinded, placebo-controlled intervention study with parallel design and four arms.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 164 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Wageningen University
- Sponsor type
- University, hospital or other
- Collaborators
- Sensus BV, Cosun Nutrition Center, Roquette Frères, Oceanium Ltd., Technical University of Eindhoven (TU/e)
- Responsible party
- Principal investigator, Yannick Vermeiren, Wageningen University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06433037
- Sponsor's protocol ID
- NL85910.091.23
- Acronym
- PRECODE
- Status last verified
- Aug 2025
- First submitted
- 17 May 2024
- Last updated
- 26 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Kruger K, van der Veen H, Beigy M, O'Donovan SD, van Riel N, Remie LB, Aarts E, Steegenga W, Smeets PAM, van Trijp MPH, de Groot LCPGM, Vermeiren Y. Gut-brain health effects of PREbiotics in older adults with suspected COgnitive DEcline: design of the PRECODE randomised placebo-controlled trial. Front Nutr. 2026 Apr 7;13:1738622. doi: 10.3389/fnut.2026.1738622. eCollection 2026.
PubMed 42022545
Study at a glance
From the registry record, last updated by the sponsor on 26 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Gut-brain Health Effects of PREbiotics in Older Adults With Suspected COgnitive DEcline: The PRECODE Study
- ClinicalTrials.gov ID
- NCT06433037
- Acronym / sponsor ID
- PRECODE / NL85910.091.23
- Conditions
- Subjective Cognitive Decline
- Keywords
- gut-brain axis, working memory, gut health, dietary fibres, prebiotics
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 164 participants (estimated)
- Lead sponsor
- Wageningen UniversityUniversity, hospital or other
- Collaborators
- Sensus BV, Cosun Nutrition Center, Roquette Frères, Oceanium Ltd., Technical University of Eindhoven (TU/e)
- Study start
- 16 Jul 2024 (actual)
- Primary completion
- Jan 2026 (estimated)
- Study completion
- Apr 2027 (estimated)
- First posted
- 29 May 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.
As people around the world are living longer, the number of individuals with dementia, particularly Alzheimer's disease (AD), is expected to triple by 2050. There's growing evidence suggesting that our gut health might play a role in the prevention of dementia. The connection between our gut and brain, known as the gut-brain axis, is becoming an important area of study. Research in animals has shown that different types of dietary fibre can improve gut health, brain function, mood, blood sugar level and the immune system and may even prevent certain harmful brain changes seen in Alzheimer's disease. Subjective Cognitive Decline (SCD) is a condition where individuals notice a decline in their mental abilities, and it can be an early sign of Alzheimer's disease.
The goal of this clinical trial is to learn if dietary fibres can improve gut and brain health in older individuals, between the ages of 60 and 79 years, who notice problems in their mental abilities, and meet the criteria of SCD. Three different dietary fibres will be given, and researchers will compare three different fibres to a placebo product to see if there is a difference between the fibres and the placebo.
The main questions it aims to answer are:
- Does dietary fibre improve working memory?
- Does dietary fibre improve other markers of brain function?
- Does dietary fibre improve gut health?
- Does dietary fibre improve the immune system and blood glucose levels?
- Does dietary fibre improve mood?
Participants will:
- Consume dietary fibres twice a day, mixed in water, tea or coffee, for a period of 26 weeks
- Have two functional MRI scans, and three additional study visits, where blood, urine and feces will be collected
- Undergo a number of neuropsychological tests, aimed at evaluating brain function
- Fill out questionnaires on their general health, mood, dietary habits, gut health
- Wear smartwatches for one week, at the beginning and the end of the study
Detailed description
Rationale: Due to the greying of society, a triplication of the number of people with dementia worldwide, with Alzheimer's disease (AD) as the commonest form, is expected by 2050. Compelling evidence points towards a crucial role of intestinal health as one potential etiological modifier of dementia, with the (microbiota) gut-brain axis (MGBA) receiving increasing attention. A number of preclinical studies have demonstrated benefit of various sources of dietary fibre for their capacity to improve gut health, cognitive functioning, general mood, glycaemia, immunogenicity, and, to inhibit tau phosphorylation, the latter which is a hallmark in AD brain. Subjective cognitive decline (SCD) lies on the continuum of AD, and subjects with this condition are at increased risk of further conversion to mild cognitive impairment (MCI) or AD. Currently, no cure is available for AD. Various symptomatic and a few disease-modifying treatments are available, but these treatments only have very limited or mild clinical effects and are often accompanied by severe side effects. Clinical follow-up studies to evaluate the effect of dietary fibre in older adults with suspected cognitive decline are required, but are still lacking to date.
Objective: The primary objective of this study is to investigate the effect of 26 weeks of supplementation with three different dietary fibres (chicory inulin, resistant dextrin, and seaweed polysaccharide) compared to a placebo (maltodextrin) on microbiota gut-brain health effects in older adults (aged 60-79) with Subjective Cognitive Decline Plus (SCD+) by assessing changes in brain function and working memory by blood oxygen level dependant (BOLD) signal activity and task accuracy during n-back task functional magnetic resonance imaging (fMRI) assessment.
The secondary objectives are to investigate the effects of 26 weeks of supplementation with dietary fibre (chicory inulin, resistant dextrin, and, seaweed polysaccharide) compared to placebo (maltodextrin) in older adults on the following parameters related to potential gut-brain pathways:
- neuropsychological test battery scoring,
- other relevant brain health parameters,
- relevant intestinal health parameters, and
- immune and metabolic parameters.
Study population: 164 older adults (60-79 years) with SCD+.
Study design implementation:
Participants will undergo assessments at baseline (T0), mid-study (T1/2, after 13 weeks) and at study end (T1, after 26 weeks. Each participant will have five study visits in total: two at T0, one at T1/2 and two at T1.
At each of the timepoints the following will be collected/performed at WUR: Sample collection (blood, urine (omitted in week 13), faeces); general cognitive assessments (see NTB; Cognitive Failure Questionnaire (CFQ) (baseline and end only), GDS-15, GAD-7); general physiological measures (blood pressure, BMI, grip-strength); dietary assessment (MIND-adjusted Eetscore, FFQ). At ZGV working memory will be evaluated using BOLD fMRI signalling and task accuracy using an n-back task paradigm. Additionally, high-resolution T1- and T2-weighted anatomical images of main regions of interest (hippocampi, (pre)frontal-, and temporal cortices) will be acquired.
For two periods of one week, corresponding with the baseline and week 26 visits, participants will wear smartwatches. These watches will be worn continuously and data will be gathered regarding cardiovascular functioning (heart rate), physical activity and mood (push messages).
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 4
- Model description
- Randomised, double-blinded, placebo-controlled intervention study with parallel design and four arms.
| Arm | Type | Receives |
|---|---|---|
| Maltodextrin | Placebo comparator | Dietary Supplement: Placebo |
| Chicory inulin | Experimental | Dietary Supplement: Chicory inulin |
| Resistant dextrin | Experimental | Dietary Supplement: Resistant dextrin |
| Seaweed polysaccharide | Experimental | Dietary Supplement: Seaweed polysaccharide |
Who may qualify
- Ages
- 60 to 79 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Written informed consent
- Fluency in Dutch (speaking, reading, writing)
- Age between 60-79 years (at screening)
- Subjective cognitive decline plus (SCD+), (criteria of Jessen et al.):
- 4.1 Self-reported worsening of memory; 4.2 Indication of repetitive concerns (worries) associated with SCD; 4.3 With at least one of the following two features present: (i) onset of SCD within the last 5 years; (ii) age at onset ≥60 years of age;
Key exclusion criteria (25 listed)
- Current participation in other intervention trials
- Technologically illiterate (complete incompetence in working with computers, apps, online questionnaires, smartwatches etc.)
- No internet access from home
- Clinical diagnosis of ≥1 of the following:
- Current or recent (<6 weeks) use of prebiotic, probiotic, or dietary fibre supplement that may modulate the microbiota, or unwilling to stop the use of supplements during the study
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 |
|---|---|---|
| Chicory inulinChicory inulin (12g/day) divided over two dosages (6g per dose) | Dietary supplement | Chicory inulin |
| Resistant dextrinResistant dextrin (14g/day) divided over two dosages (7g per dose) | Dietary supplement | Resistant dextrin |
| Seaweed polysaccharideSeaweed polysaccharide (1g/day) divided over two dosages (0.5g per dose). Additionally contains 7g/day of placebo as a volumetric and isocaloric filler. | Dietary supplement | Seaweed polysaccharide |
| PlaceboMaltodextrin (7g/day) will be provided in two divided doses (3.5g per dose) | Dietary supplement | Maltodextrin |
Primary outcome
Effect on working memory during n-back task fMRI
Time frame: Measured at baseline and week 26
Effects on working memory will be assessed by blood-oxygen level dependant (BOLD) signal activity during 2-back task performed during fMRI scanning
Effect on working memory performance during n-back task fMRI
Time frame: Measured at baseline and week 26
Effects on working memory performance will be assessed by task accuracy during 2-back task performed during fMRI scanning
25 secondary outcomes
Effect on cognitive functioning as measured by a neuropsychological test battery
Time frame: Measured at baseline, week 13 and week 26
Effect on ADAS-Cog Word Recall cognitive assessment (episodic memory)
Time frame: Measured at baseline, week 13 and week 26
Effect on ADAS-Cog Word Recognition cognitive assessment (episodic memory)
Time frame: Measured at baseline, week 13 and week 26
Effect on Digit Symbol Substitution Test cognitive assessment (executive function)
Time frame: Measured at baseline, week 13 and week 26
Effect on Digit Span Backward Task cognitive assessment (working memory)
Time frame: Measured at baseline, week 13 and week 26
Effect on Category Fluency Test cognitive assessment (executive function)
Time frame: Measured at baseline, week 13 and week 26
Effect on ADAS-Cog Orientation cognitive assessment (episodic memory)
Time frame: Measured at baseline, week 13 and week 26
Effect on tryptophan metabolites
Time frame: Measured at baseline and week 26
Effect on amyloid-beta (Aβ) biomarker
Time frame: Measured at baseline and week 26
Effect on neuroplasticity
Time frame: Measured at baseline and week 26
Effect on brain regions of interest
Time frame: Measured at baseline and week 26
Effect on hypothalamic-pituitary adrenal axis
Time frame: Measured at baseline and week 26
Effect on intestinal barrier integrity
Time frame: Measured at baseline, week 13 and week 26
Effect on intestinal inflammation
Time frame: Measured at baseline, week 13 and week 26
Effect on gastrointestinal transit time
Time frame: Measured at baseline, week 13 and week 26
Effect on gastrointestinal symptoms
Time frame: Measured at baseline, week 13 and week 26
Effect on self-reported stool consistency
Time frame: Measured at baseline, week 13 and week 26
Effect on stool consistency
Time frame: Measured at baseline, week 13 and week 26
Effect on qualitative faecal microbiota composition
Time frame: Measured at baseline, week 13 and week 26
Effect on quantitative faecal microbiota composition
Time frame: Measured at baseline, week 13 and week 26
Effect on faecal metabolites
Time frame: Measured at baseline, week 13 and week 26
Effect on faecal pH
Time frame: Measured at baseline, week 13 and week 26
Effect on immune parameters
Time frame: Measured at baseline, week 13 and week 26
Effect on glucose homeostasis
Time frame: Measured at baseline, week 13 and week 26
Effect on lipid profile
Time frame: Measured at baseline, week 13 and week 26
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Aug 2025.
- Derived from this study: PubMed 42022545Kruger K, van der Veen H, Beigy M, O'Donovan SD, van Riel N, Remie LB, Aarts E, Steegenga W, Smeets PAM, van Trijp MPH, de Groot LCPGM, Vermeiren Y. Gut-brain health effects of PREbiotics in older adults with suspected COgnitive DEcline: design of the PRECODE randomised placebo-controlled trial. Front Nutr. 2026 Apr 7;13:1738622. doi: 10.3389/fnut.2026.1738622. eCollection 2026.
- Individual participant dataSharing planned: No
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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 Chicory inulin, Resistant dextrin and Seaweed polysaccharide in people with Subjective Cognitive Decline, run by Wageningen University at 1 site in Netherlands.
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 6 inclusion and 25 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: under way, not looking for participants, as of the sponsor's last update on 26 Aug 2025. 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 Netherlands. 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?
This study is still under way. Results are not available in the source record yet.
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?
Effect on working memory during n-back task fMRI (time frame: Measured at baseline and week 26). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06433037, which also lists 1 linked publication.
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 Aug 2025.