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Completed

NCT Number: NCT06333717

Impact of Whole Grain Rye Bread on Health

This randomized controlled trial aims to study how a high intake of a fibre-rich bread affects the composition and functioning of the gut microbiota in healthy subjects, and how this, in turn, impacts on the release of gut peptides, intestinal permeability, stress and cognitive performance.

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Key information

Conditions

Healthy Diet

Age range

18 year–44 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Örebro University

Örebro, Sweden

About this study

Healthy subjects will be recruited for a 3-week, randomized, parallel-controlled study. Subjects that are eligible to take part in the study will be blinded and randomly allocated to consume a fibre-rich bread or a control bread daily for 3 weeks. Measurements of biomarkers related to the gut-brain axis, microbiota composition and functioning, intestinal permeability, stress and cognitive functioning will be conducted on two separate test days, at baseline and after the 3 weeks intervention. On both test days (day 0 and day 21) subjects will come to the study centre after a 10 hours overnight fast and will deliver faecal samples collected at home. At the study centre, blood samples will be collected and a device for continuous assessment of autonomic nervous system response (Biopac) will be placed. Subjects will drink a multisugar solution and urine samples will be collected for gut permeability analysis. Sugar solution intake will be followed by a baseline period during which participants will rest for 30 minutes to adapt to the laboratory setting. After the baseline period, subjects will conduct a stress test and cognitive tests. Visual analogue scales (VAS) to assess momentary perceived stress levels and saliva samples will be collected before and after the stress test. The study subjects will also complete questionnaires at both visits (food frequency questionnaire, food diary, physical activity, gastrointestinal symptom rating scale, Euro Quality of Life).

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 18-44 years
  • Body mass index (BMI) 18,5-30 kg/m2 (normal weight or overweight)

Exclusion criteria

  • Significant acute or chronic illness, including an inflammatory or a functional disease of gastrointestinal track and psychiatric and psychological disorders
  • Anxiety or depression (according to Hospital Anxiety and Depression Scale (HADS score) and Depression Anxiety Stress Scale (DASS-21 score))
  • Use of a medication that may interfere with the study (e.g. cannabis, antipsychotics, anxiolytics, antidepressants, proton-pump inhibitors)
  • Abuse of alcohol or drugs (according to AUDIT score)
  • Use of antibiotic medication within the past 3 months before the study
  • Use of laxative or anti-diarrhoea medication within the past 3 months before the study
  • Regular consumption of probiotic or prebiotic product for the past 6 weeks before the study
  • A diet that may interfere with the study (such as gluten free or low-carb diet)
  • Smoking
  • Pregnancy or breastfeeding
  • Premenopausal female with irregular or short menstruation cycle and not using hormonal contraception
  • Colour blindness, dyslexia or dyscalculia
  • Unable to absent from caffeine, alcohol or intense exercise for 12 hours prior measurements.

Treatment and study plan

Whole grain bread

Dietary Supplement

Consumption of high-fibre bread as a dietary supplementation

Control bread

Dietary Supplement

Consumption of control bread as a dietary supplementation

Primary outcomes

  1. Microbiota composition baseline vs after intervention using 16S RNA gene sequencing

    Time frame: faecal samples collected before and after intake of bread for 3 weeks

    Difference in gut microbiota composition in faecal samples before (baseline) and after intake of six slices of bread for 3 weeks (after intervention) using 16S RNA gene sequencing

Secondary outcomes

  1. Microbiota composition whole grain rye bread vs control bread using 16S RNA gene sequencing

    Time frame: faecal samples collected before and after intake of bread for 3 weeks

    Difference in gut microbiota composition in faecal samples between the study arms using 16S RNA gene sequencing

  2. Concentrations of circulatory short-chain fatty acids SCFA

    Time frame: blood samples collected before and after intake of bread for 3 weeks

    Difference in blood levels of SCFA between and within intervention groups after intake of bread for 3 weeks

  3. Concentrations of faecal SCFA

    Time frame: faecal samples collected before and after intake of bread for 3 weeks

    Difference in faecal levels of SCFA between and within intervention groups after intake of bread for 3 weeks

  4. Concentrations of blood glucagon like peptide-1 (GLP-1)

    Time frame: blood samples collected before and after intake of bread for 3 weeks

    Difference in blood levels of GLP-1 between and within intervention groups after intake of bread for 3 weeks

  5. Concentrations of blood glucagon like peptide-2 (GLP-2)

    Time frame: blood samples collected before and after intake of bread for 3 weeks

    Difference in blood levels of GLP-2 between and within intervention groups after intake of bread for 3 weeks

  6. Concentrations of blood peptide YY (PYY)

    Time frame: blood samples collected before and after intake of bread for 3 weeks

    Difference in blood levels of PYY between and within intervention groups after intake of bread for 3 weeks

  7. Concentrations of blood gastric inhibitory polypeptide (GIP)

    Time frame: blood samples collected before and after intake of bread for 3 weeks

    Difference in blood levels of GIP between and within intervention groups after intake of bread for 3 weeks

  8. Concentrations of blood neuroactive peptide Y (NPY)

    Time frame: blood samples collected before and after intake of bread for 3 weeks

    Difference in blood levels of NPY between and within intervention groups after intake of bread for 3 weeks

  9. Concentrations of blood brain-derived neurotrophic factor (BDNF)

    Time frame: blood samples collected before and after intake of bread for 3 weeks

    Difference in blood levels of BDNF between and within intervention groups after intake of bread for 3 weeks

  10. Concentrations of blood cytokines

    Time frame: blood samples collected before and after intake of bread for 3 weeks

    Difference in blood levels of cytokines between and within intervention groups after intake of bread for 3 weeks

  11. Concentrations of blood alkylresorcinols

    Time frame: blood samples collected before and after intake of bread for 3 weeks

    Difference in blood levels of alkylresorcinols between and within intervention groups after intake of bread for 3 weeks

  12. Concentrations of blood lipopolysaccharide-binding protein (LBP)

    Time frame: blood samples collected before and after intake of bread for 3 weeks

    Difference in blood levels of LBP between and within intervention groups after intake of bread for 3 weeks

  13. Concentrations of blood soluble CD-14 (sCD-14)

    Time frame: blood samples collected before and after intake of bread for 3 weeks

    Difference in blood levels of sCD-14 between and within intervention groups after intake of bread for 3 weeks

  14. Concentrations of sugars in urine

    Time frame: urine samples collected before and after intake of bread for 3 weeks

    Difference on intestinal permeability between and within intervention groups after intake of bread for 3 weeks measured by the excretion of sugars contained in a multi-sugar solution

  15. Concentrations of saliva cortisol during stress test

    Time frame: Saliva samples collected before the stress test, after the introduction phase, directly after the acute stress phase, 5 minutes, 10-15 minutes, 60 minutes, and 75 minutes after the stress test

    Difference in saliva levels of cortisol produced during stress test between and within intervention groups after intake of bread for 3 weeks

  16. Concentrations of saliva alpha-amylase during stress test

    Time frame: Saliva samples collected before the stress test, after the introduction phase, directly after the acute stress phase, 5 minutes, 10-15 minutes, 60 minutes, and 75 minutes after the stress test

    Difference in saliva levels of a-amylase produced during stress test between and within intervention groups after intake of bread for 3 weeks

Other outcomes

  1. Gastrointestinal symptoms measured by Gastrointestinal Symptom Rating Scale in Irritable Bowel Syndrome (GSRS-IBS)

    Time frame: 3 weeks

    Difference in the frequency and severity of gastrointestinal symptoms between and within intervention groups after the intake of bread for 3 weeks. The GSRS-IBS contains 13 self-report items rated on a 6-point Likert scale ranging from 1 (no discomfort at all) to 7 (very severe discomfort). Total scores range from 0 to 78.

  2. Food habits measured by an electronic food frequency questionnaire Mealq

    Time frame: 3 weeks

    Survey of participants' food habits before and during the intake of bread for 3 weeks

  3. Food habits measured by a Food diary

    Time frame: 3 days

    Survey of participants' food habits before and during the intake of bread for 3 weeks

  4. Physical activity measured by the International Physical Activity Questionnaire (IPAQ)

    Time frame: 3 days

    Survey of participants' physical activities before and during the intake of bread for 3 weeks. The IPAQ contains 7 self-report questions and the categorical score is divided into 3 levels: low (less than 600 metabolic equivalent-minutes/week), moderate (at least 600 metabolic equivalent-minutes/week) or high (at least 1500 metabolic equivalent-minutes/week).

  5. Quality of life measured by the Euro Quality of Life questionnaire

    Time frame: once before and after intake of bread for 3 weeks

    Survey of participants' well-being before and during the intake of bread for 3 weeks. It records the patient's self-rated health on a vertical visual analogue scale where the endpoints are labelled from 0 (worst imaginable health state) to 100 (best imaginable health state).

  6. Perceived stress measured by a Visual analog scale questionnaire

    Time frame: before the stress test, after the introduction phase, directly after the acute stress phase, 5 minutes, 10-15 minutes, 60 minutes, and 75 minutes after the stress test

    Difference in the perceived stress during a stress test between and within intervention groups after the intake of bread for 3 weeks

  7. Cognitive control using Eriksen flanker task (Flanker task)

    Time frame: once before and after intake of bread for 3 weeks

    Difference in cognitive control between and within intervention groups after the intake of bread for 3 weeks

  8. Working memory performance using a modified N-back task combined with recent-probes item-recognition task (Sternberg task)

    Time frame: once before and after intake of bread for 3 weeks

    Difference in working memory between and within intervention groups after the intake of bread for 3 weeks

  9. Electrocardiogram (ECG) using the Biopac system

    Time frame: once before and after intake of bread for 3 weeks

    Difference in heart rate variability during a stress test between and within intervention groups after the intake of bread for 3 weeks

  10. Electrodermal activity (EDA) using the Biopac system

    Time frame: once before and after intake of bread for 3 weeks

    Difference in skin conductivity during a stress test between and within intervention groups after the intake of bread for 3 weeks. Electrodes to measure EDA will be placed on the subjects' left palm. Skin conductivity measures will include skin conductivity level (SCL), the number of skin conductivity responses (SCR), and the amplitude of SCR.

Sponsors and collaborators

Lead sponsor

Örebro University, Sweden

Other

Registry information

Official study title

Impact of Whole Grain Rye Bread on Modulating Microbiota-gut-brain Axis in Healthy Subjects

Acronym: FBS

Important dates

Study start
2021
Primary completion
2021
Study completion
2021
First posted
Mar 27, 2024
Registry last updated
Mar 27, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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