The effects of butyrate on psychobiological processes are examined in a sample of healthy volunteers.
The study is an interventional triple-blind, placebo-controlled, parallel group design with 2 arms (placebo, butyrate). Healthy male participants adhere to a low-fiber diet for the duration of the study (11 days). At the baseline study visit, measurements are taken in the lab, including biological samples and psychophysiological measurements. Participants then consume placebo or butyrate for 1 week and revisit the lab on day 11 for a second measurement of the outcomes of interest. Specifically, we investigate the effect of colonic butyrate administration on affective processing, including stress sensitivity and fear-related processes (e.g. extinction learning). Volunteers also respond to questionnaires in relation to mood and GI symptoms, and provide biological samples (saliva, blood, and faecal samples) for analysis of cortisol levels, circulating short chain fatty acids and serum BDNF, and faecal SCFA, respectively.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
72
UZ Leuven/Stresslab
Leuven, I Am Not in the U.S. Or Canada, Belgium
Stress sensitivity (cortisol)
Induction of cognitive, physical, and social stress using Maastricht Acute Stress Test. Stress hormone cortisol is quantified by gathering multiple saliva samples throughout the stress induction and recovery during both pre-intervention and post-intervention visit.
Time frame: through study completion, on average 1 year and 5 months
Stress sensitivity (subjective)
Induction of cognitive, physical, and social stress using Maastricht Acute Stress Test. Participant rate how much stress, discomfort, and pain they feel on a 10-cm visual analogue scale, with higher values indicating greater stress, discomfort, and pain. This is done prior to stress induction, in the middle, and at the end at both pre- and post-intervention visits.
Time frame: through study completion, on average 1 year and 5 months
Cortisol awakening response
Measuring chronic stress by quantifying cortisol in morning samples (5 samples taken form the moment of waking every 15 minutes for 1 hour) on the morning of the pre- and post-intervention visits.
Time frame: through study completion, on average 1 year and 5 months
Fear
Exploring fear-related processes (conditioning, extinction, recall, and renewal) by means of a computerised task. Fear response is measured using skin conductance, and a skin conductance response is calculated.
Time frame: through study completion, on average 1 year and 5 months
Fear (subjective)
Exploring fear-related processes (conditioning, extinction, recall, and renewal) by means of a computerised task. Fear response is measured subjectively by asking participants to indicate their expectancy of an aversive stimulus.
Time frame: through study completion, on average 1 year and 5 months
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Positive and Negative Affect Schedule (PANAS)
Assessing ratings on the subscales of PANAS, positive and negative affect. PA subscale scores range between 10-50, with higher scores indicating better outcome. NA subscale scores range between 10-50, with higher scores indicating worse outcome.
Time frame: through study completion, on average 1 year and 5 months
Perceived Stress Scale (PSS)
Assessing ratings on PSS. Scores range between 0-40 with higher scores indicating worse outcome.
Time frame: through study completion, on average 1 year and 5 months
Depression, anxiety, and stress scales (DASS-21)
Assessing ratings on the subscales of DASS-21, depression, anxiety, and stress subscales. Higher scores on these subscales indicates a worse outcome. Normal (depression: 0 - 4; anxiety: 0 - 3; stress: 0 - 7), Mild (depression: 5 - 6; axiety: 4 - 5; stress: 8 - 9), Moderate (depression: 7 - 10; anxiety: 6 - 7; stress: 10 - 12), Severe (depression: 11 - 13; anxiety: 8 - 9; stress: 13 - 16), Extremely Severe (depression: 14 +; anxiety: 10 +; stress: 17 +).
Time frame: through study completion, on average 1 year and 5 months
Leiden Index of Depression Sensitivity-Revised (LEIDS-R)
Assessing ratings on the subscales of LEIDS-R and its total score. This is a self-report on cognitive reactivity comprised of 34 items with six subscales. Hopelessness/suicidality; Acceptance/Coping; Aggression; Control/Perfectionism; Risk Aversion; Rumination.
Time frame: through study completion, on average 1 year and 5 months
Gastrointestinal symptom rating scale (GSRS)
Assessing ratings on the subscales of GSRS and its total score. It has 5 subscales (Reflux, Diarrhea, Constipation, Abdominal Pain, and Indigestion Syndrome). Subscale scores range from 1 to 7 and higher scores indicates a worse outcome.
Time frame: through study completion, on average 1 year and 5 months
Serum SCFA
Quantification of serum SCFA (μM) at pre- and post-intervention
Time frame: through study completion, on average 1 year and 5 months
Faecal SCFA
Quantification of faecal SCFA in samples provided at pre- and post-intervention
Time frame: through study completion, on average 1 year and 5 months
Serum BDNF
Quantification of fasting serum BDNF levels (µg/mL)
Time frame: through study completion, on average 1 year and 5 months