Impact of High Fiber and Vegetal Protein Diet on Gut Health and Immunity Biomarkers in Prediabetic Patients (PreVegDiet)

May 2, 2026 updated by: DR ADELE COSTABILE, University of Roehampton

University of Roehampton

The research area that focuses on the links between nutrition and health, nutrition and the immune system as well as nutrition-related public health interventions, which often falls into the gap between the agricultural and health domains. The rationale of this project is to study the influence of beneficial diets on the immune system of pre-diabetic patients and its potential to counteract infections. A clinical, an in vitro (cell systems) and an in vivo (animal model) approach will be used to study the influence of a seaweed bioactive supplement and a diet rich in components from a Mediterranean diet on a Salmonella typhimurium infection in prediabetic subjects. At the end of this project, we will provide evidence on the potential of these nutritional interventions to counteract infection, which are of high relevance to the society to reduce the burden of type 2 diabetes (T2DM) and obesity. This research is part of an ongoing research project funded by the Research State Agency (Spain), Health Research Board (HRB, Ireland) and the Medical Research Council (MRC-UKRI, UK) via the NUTRIMMUNE' Grant of the Joint Programming Initiative a Healthy Diet for a Healthy Life (JPI-HDHL).

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The aim of this study is to evaluate the effects of different diets on gut health, immune and metabolic markers, in individuals aged between 18-65 years who are defined as pre-diabetics and adults in general good health.

About 45 volunteers will take part in this study and they will then be randomly assigned a volunteer number and placed in one of three study group for a total of 12 weeks:

  1. Normal Healthy Diet group (N=15): Participants aged 18-65 years in general good health will be following the Eatwell booklet advice*and NICE/NHS guidelines (https://www.nice.org.uk/).
  2. Placebo group (N=15): Participants aged 18-65 prediabetics will take 2 capsules/day (750mg Maltodextrin placebo comparator) before each of the two main meals without any advice on the diet to follow.
  3. Seaweed Group.: Participants aged 18-65 prediabetics will take 2 seaweeds brown extract capsules/day (information detailed in the safety product sheet, total dose of 700 mg before each of the two main meals. All participants will be advised on product storage and use conditions prior to use to ensure product consistency throughout the period of the study.

At baseline (week 0), week 6, week 12 and week 16, volunteers will be required to visit the University of Roehampton to provide fasted blood, saliva, stool and first pass urine samples and have blood pressure, body fat and weight measured.

During the study period, they will be asked to complete some questionnaire to assess your gastrointestinal symptoms along with daily stool habits and diet habits.

Study Type

Interventional

Enrollment (Actual)

45

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United Kingdom
    • UK
      • London, UK, United Kingdom, SW15 4JD
        • Health Sciences Research Centre, Life Sciences Department, University of Roehampton

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion criteria

  • Adults aged between 18 and 60 years, with
  • Fasting blood glucose level of 5.6-6.9mmol/L or impaired HbA1c (HbA1c level of 5.7%-6.4%)
  • Fasting blood glucose level below 5.6mmol/L or HbA1c level below 5.7%.
  • For intervention purposes, eligible participants are also required to have a mobile phone and be able to read and speak English.

Exclusion criteria

  • People with a current diagnosis or clinical history of T2DM
  • People with comorbid conditions that may limit participation in the study, such as a history of an acute cardiovascular event, uncontrolled hypertension, cancer or major psychiatric or cognitive problems.
  • People who are already participating in a weight loss programme
  • People receiving drug treatment for pre-diabetes (eg, metformin)
  • People with a history of long-term use of medicines known to influence glucose metabolism (eg, corticosteroids)
  • People with elevated liver enzymes (alanine aminotransferase ≥300 IU/L, aspartate aminotransferase ≥300 IU/L)
  • People who take antibiotics or bacterial agents (Probiotics) within 1 month
  • Pregnant women, women ready for pregnancy, and nursing mothers

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Normal Healthy Diet group
Participants aged 18-65 years in general good health will be following the Eatwell booklet advice*and NICE/NHS guidelines (https://www.nice.org.uk/).
Other: Normal Healthy Diet
Participants aged 18-65 years in general good health will be following the Eatwell booklet advice*and NICE/NHS guidelines (https://www.nice.org.uk/).
Other Names:
  • Eatwell diet Control
Placebo Comparator: Placebo Group
Participants aged 18-65 prediabetics will take 2 capsules/day (750mg Maltodextrin placebo comparator) before each of the two main meals without any advice on the diet to follow.
Other: Placebo Diet Group
Participants aged 18-65 prediabetics will take 2 capsules/day (750mg Maltodextrin placebo comparator) before each of the two main meals without any advice on the diet to follow.
Active Comparator: Seaweed Group
Participants aged 18-65 prediabetics will take 2 seaweeds brown extract capsules/day (information detailed in the safety product sheet, total dose of 700 mg before each of the two main meals. All participants will be advised on product storage and use conditions prior to use to ensure product consistency throughout the period of the study.
Dietary supplement: Seaweed Group
Participants aged 18-65 prediabetics will take 2 seaweeds brown extract capsules/day (information detailed in the safety product sheet, total dose of 700 mg before each of the two main meals. All participants will be advised on product storage and use conditions prior to use to ensure product consistency throughout the period of the study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in blood glucose levels
Time Frame: Changes from baseline to 6 and 12 weeks of the intervention
To investigate the effects of dietary intervention on blood glucose levels of pre-diabetics
Changes from baseline to 6 and 12 weeks of the intervention
Changes in insulin sensitivity
Time Frame: Changes from baseline to 6 and 12 weeks of the intervention
To investigate the effects of dietary intervention on insulin levels of pre-diabetics
Changes from baseline to 6 and 12 weeks of the intervention
Changes in gut microbiome
Time Frame: Changes from baseline to 6 and 12 weeks of the intervention
To investigate the effects of dietary intervention on gut microbiome of pre-diabetics
Changes from baseline to 6 and 12 weeks of the intervention
Changes in pro and anti-inflammatory biomarkers
Time Frame: Changes from baseline to 6 and 12 weeks of the intervention
To investigate the effects of dietary intervention on immunity of pre-diabetics
Changes from baseline to 6 and 12 weeks of the intervention
Changes in metabolic profile
Time Frame: Changes from baseline to 6 and 12 weeks of the intervention
To investigate the effects of dietary intervention on metabolic signature of pre-diabetics
Changes from baseline to 6 and 12 weeks of the intervention
Changes in dietary habits
Time Frame: Changes from baseline to 6 and 12 weeks of the intervention
To investigate the effects of dietary intervention on dietary habits of pre-diabetics
Changes from baseline to 6 and 12 weeks of the intervention
Changes in blood pressure
Time Frame: Changes from baseline to 6 and 12 weeks of the intervention
To investigate the effects of dietary intervention on blood pressure of pre-diabetics
Changes from baseline to 6 and 12 weeks of the intervention
Changes in quality of life
Time Frame: Changes from baseline to 6 and 12 weeks of the intervention
To investigate the effects of dietary intervention on quality of life of pre-diabetics
Changes from baseline to 6 and 12 weeks of the intervention

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Roehampton

Collaborators

Universitat Autonoma de Barcelona
University College Cork

Investigators

  • Study Director: ADELE COSTABILE, Dr, University of Roehampton

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 13, 2023

Primary Completion (Actual)

July 17, 2024

Study Completion (Actual)

December 12, 2025

Study Registration Dates

First Submitted

November 14, 2023

First Submitted That Met QC Criteria

November 19, 2023

First Posted (Actual)

November 27, 2023

Study Record Updates

Last Update Posted (Actual)

May 7, 2026

Last Update Submitted That Met QC Criteria

May 2, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • LSC 23/388

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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