The Effects of Dietary Fibres on Metabolic Health and the Gut Microbiome

The Modulatory Effects of Dietary Fibres on the Composition and Function of the Gut Microbiome- A Pilot Randomised Placebo-controlled Dietary Intervention Study

The study involves intake of dietary supplements, which are commonly found in the UK diet (not pharmacological agents) to test their effects on inflammation in the body and gut microbiome composition. Study subjects will be healthy volunteers recruited from the University and local population and will be asked to attend the laboratory on 2 occasions; before and after 4-week' supplementing the diet daily with either the dietary fibres (the current trial focussed on pectin) or placebo (maltodextrin). At each study visit (~3hrs), participants will be asked to provide a stool and blood sample and will have blood pressure measured. In the week before each study visit, participants will record their food intake.

Study Overview

• Status: Completed
• Conditions: Healthy; Diet; Systemic Inflammatory Response
• Intervention / Treatment: Dietary supplement: Pectin; Dietary supplement: Maltodextrin

Detailed Description

The overall aim of the proposed project is to unlock the effect of dietary fibres (i.e. LM Pectin) on anti-inflammatory and cardioprotective metabolic responses via the modulation of the gut microbiome and SCFAs production.

Specific Aim 1: To deliver a wealth of molecular data, including effect sizes, on the physiological effects of dietary fibres on the changes in the composition and function of the gut microbiome and changes in the metabolomic and physiological profile of an individual.

Specific Aim 2: To investigate the mechanisms whereby the gut microbiome modulates crucial physiological parameters such, blood glucose regulation, hunger and appetite, immune function markers in response to the anti-inflammatory effects of the gut microbiome.

30 healthy, non-obese volunteers will be recruited following a successful medical screening. Between recruitment and first study visit, and in the final week of the 4-week intervention (before the second study visit), participants will be asked to complete a dietary record (4 days), to collect a stool sample on the day before the study visit and to fast from midnight the night before this visit.

At both study visits, participants will have weight, hip/waist circumference and blood pressure measured. They will be asked to complete some questionnaires. After completion of the first study day, participants will be randomised to receive either the dietary fibre or placebo powder. They will be given the blinded products portioned in individual sachets, with instructions to add the contents of one sachet a day to juice, smoothies or water and to consume immediately. Study visit 2 will be scheduled at the end of the 4 week 'dosing' period.

• Study Type: Interventional
• Enrollment (Actual): 19
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Nottingham, United Kingdom, NG7 2UH
    • University of Nottingham

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Participant is willing and able to give informed consent for participation in the study
• Participant eligibility includes those aged >18 years who have a body mass index (BMI) between 18.5 and 39.9 kg/m2

Exclusion Criteria:

The participant may not enter the study if ANY of the following apply:

• Have psychosocial or gastrointestinal (e.g. malabsorptive conditions such as IBS/IBD, coeliac)
• Are taking the following medications: immunosuppressants, amiodarone and/or perhexiline
• Are currently following or anticipated to commence a specialised commercially available weight loss diet and/or program/ taking prebiotic supplements
• Pregnant or breastfeeding
• History or current psychiatric illness
• History or current neurological condition (e.g. epilepsy)
• Having taken part in a research study in the last 3 months involving invasive procedures or an inconvenience allowance.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Fibre arm (Pectin); 20g of pectin was provided to healthy volunteers for 4 weeks.	Dietary supplement: Pectin; Pectin fibre (20g) was randomly allocated to eligible participants in order to test specific effects on gut microbiome composition and metabolic markers.
Placebo Comparator: Maltodextrin; 10g of maltodextrin was provided to healthy volunteers for 4 weeks	Dietary supplement: Maltodextrin; Maltodextrin (10g) served as a control/ placebo to compare the effects observed with pectin.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in microbiome profile	Change in microbiome profile, assessed using 16s RNA sequencing analysis of faecal samples provided pre and post the 4-week intervention period	4 weeks
Change in inflammatory profile	Change in circulating markers of inflammation measured by ELISAs in serum samples collected pre and post the 4-week intervention period.	4 weeks
Changes in short chain fatty acids (SCFAs)	Change in serum SCFAs measured by mass spectrometry pre and post the 4-week intervention period	4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in systolic blood pressure (lying to standing) pre intervention	Change in systolic blood pressure (measured after 3 minutes of lying down and after 1 minute of standing), at pre-intervention study visit	4 minutes
Change in systolic blood pressure (lying to standing) post intervention	Change in systolic blood pressure (measured after 3 minutes of lying down and after 1 minute of standing), at post-intervention study visit	4 minutes
Change in Pittsburgh Sleep Quality Index (PSQI)	Change in PSQI score (min score 0, max 21), measured pre and post the 4-week intervention, with higher score indicating poorer sleep quality	4 weeks
Change in diastolic blood pressure (lying to standing) pre intervention	Change in diastolic blood pressure (measured after 3 minutes of lying down and after 1 minute of standing), at pre-intervention study visit	4 minutes
Change in diastolic blood pressure (lying to standing) post intervention	Change in diastolic blood pressure (measured after 3 minutes of lying down and after 1 minute of standing), at post-intervention study visit	4 minutes
Change in Short Form Health Survey (SF12) Questionnaire aggregated normalised 'physical' score	Change in 'SF12' Questionnaire aggregated 'physical' score (normalised to UK population) calculated according to standard procedures (min 0, max 100), with higher score indicating better physical wellbeing; measured pre and post intervention	4 weeks
Change in Short Form Health Survey (SF12) Questionnaire aggregated normalised 'mental' score	Change in 'SF12' Questionnaire aggregated 'mental' score (normalised to UK population) calculated according to standard procedures (min 0, max 100), with higher score indicating better mental wellbeing; measured pre and post intervention	4 weeks
Change in Hospital Anxiety and Depression Score (HADS)	Change in anxiety score (min score 0, max 3 with higher score indicating higher anxiety like symptoms), and depression score (min 3, max 0 with lower the scores indicating higher depression like symptoms) measured pre and post the 4-week intervention.	4 weeks

Collaborators and Investigators

• Sponsor: Elizabeth Simpson
• Investigators: Principal Investigator: Ana Valdes, Professor, University of Nottingham

Study record dates

Study Major Dates

• Study Start (Actual): September 9, 2021
• Primary Completion (Actual): September 9, 2022
• Study Completion (Actual): September 9, 2022

Study Registration Dates

• First Submitted: August 28, 2024
• First Submitted That Met QC Criteria: August 28, 2024
• First Posted (Actual): August 30, 2024

Study Record Updates

• Last Update Posted (Actual): August 30, 2024
• Last Update Submitted That Met QC Criteria: August 28, 2024
• Last Verified: August 1, 2024

More Information

Terms related to this study

• Keywords: Systemic inflammation; Gut microbiome; Dietary intervention
• Other Study ID Numbers: FMHS 302-0621

Drug and device information, study documents

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