The Effects of an 8-week Vegan Diet on TMAO Levels and Post-challenge Glucose Levels in Individuals With Dysglycaemia (PYH)

January 29, 2020 updated by: University of Leicester

The Effects of an 8-week Vegan Diet on Trimethylamine-N-Oxide (TMAO) Levels and Post-challenge Glucose Levels in Individuals With Dysglycaemia (The Plant Your Health Study)

The amount of people with diabetes mellitus has now reached over 4 million in the United Kingdom. Type 2 diabetes accounts for the majority of all cases of diabetes and increases the risk of many other diseases such as heart problems. Plant based diets are thought to be an effective way to improve markers of health related to type 2 diabetes and heart disease. One way that a plant based diet improves health could be through reducing waste products that are generated in the gut by the bacteria that break down food as part of the digestion process. For example, the digestion of some meats, fish and eggs results in the creation of a substance called Trimethylamine-N-Oxide (TMAO) which has been linked to worse health outcomes in several studies. However, the full impact on TMAO and blood glucose levels of swapping regular meat consumption for a plant based vegan diet is not fully understood and requires further research. Therefore, the aim of this study will be to develop and undertake a clinical trial to investigate the effects of an 8-week vegan diet on TMAO levels and post challenge glucose levels in individuals with dysglycaemia (drug naïve).

The study will be interventional single group prospective trial of adults aged 18-75 years of age from a multi-ethnic population with dysglycaemia (drug naïve). A sample of 29 people will be sought. The dietary intervention (vegan diet) will last 8 weeks. Then, the participants will go back to their normal diet and come for their final visit after a four week follow-up period (week 12). To assess the effectiveness of the intervention, primary and secondary outcome data collected at baseline will be compared with data collected at 1 week, 8 weeks and 12 weeks.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Study Design

Interventional single group prospective trial in a patient population with identified dysglycaemia within the past 36 months defined as 2h post-challenge glucose ≥7.8 mmol/L after a standard oral glucose tolerance test or HbA1c ≥5.7% (39-46 mmol/mol). This phase clinical trial will evaluate the efficacy and underlining mechanisms of a vegan diet in promoting cardiometabolic health in those with dysglycaemia. Specifically, this trial will aim to investigate the effect of an 8-week vegan diet with follow-up at 1, 8 and 12 weeks.

Study Setting

The study will be co-ordinated within the Leicester Biomedical Research Centre (Leicester Diabetes Centre) at the Leicester General Hospital. Clinical measurement sessions will be carried out by the appointed research team. Participants will be asked to visit the study centre on five occasions.

Intervention Description and Definition

The participants will be asked to follow a diet that excludes foods hypothesised to support the syntheses of TMAO, particularly meat (any), eggs and fish (any). A number of studies suggest that dairy products may also have an effect in modulating TMAO production whereas other studies do not. Therefore, in order to avoid any potential contaminating or confounding effect, dairy products will also be avoided.

The diet employed in this study is broadly aligned to a vegan diet. The term vegan will be used to aid behaviour change and food choice. For example, an increasing array of products are now pack marked as vegan. The participants will be asked to keep their diet similar to their original and the Registered Dietitian involved in this study will plan their weekly menus accordingly.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
28

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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
      • Leicester, United Kingdom, LE3 4PW
        • Leicester Diabetes Centre

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Participant is willing and able to give informed consent for participation in the study

  • And either:

    • Overweight (White: BMI>25 - <30, South Asian/ Black and minority ethnic group <27.5) with HbA1c between HbA1c ≥5.7% and ≤ 8% (39-64 mmol/mol) identified within the last 36 months
    • Obese: (White: BMI ≥30, South Asian/ Black and minority ethnic group: ≥27.5)
  • Male or Female
  • Aged 18 - 75 years inclusive
  • Able to understand, read and speak the English language to a sufficient level to understand and take part to the study in the investigators opinion
  • Have access to a phone, and willing to use it as part of the study
  • Regular meat and/or fish eater (at least 3 times per week)-self reported

Exclusion Criteria:

Participant is unwilling or unable to give informed consent

  • Non-English speakers
  • HbA1c above 8% (64 mmol/mol)
  • Taking any form of glucose lowering medication currently or within the last 60 days
  • Current smokers
  • Current use of vegan or vegetarian diet
  • Recent significant weight change (10% or more) over the last 3 months
  • Pregnancy/lactation
  • Clinical eating disorder as detected by their GP or relevant health professional (e.g. dietitian)
  • Have a terminal illness
  • Current or recent (within 6 months) oral antibiotics or steroid use as their usage could impact on the gut bacteria profile

  • Ongoing CVD (e.g. angina) *

    • In the circumstance that an individual is not sure whether they meet the inclusion/ exclusion criteria, (i.e. they are not sure if they have ongoing CVD) this will be reviewed by a named medic on the delegation of authority log for a clinical decision to be made during baseline.

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: Prevention
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Vegan diet

Intervention Description and Definition The participants will be asked to follow a diet that excludes foods hypothesised to support the syntheses of TMAO, particularly meat (any), eggs and fish (any). A number of studies suggest that dairy products may also have an effect in modulating TMAO production whereas other studies do not. Therefore, in order to avoid any potential contaminating or confounding effect, dairy products will also be avoided.

The diet employed in this study is broadly aligned to a vegan diet. The term vegan will be used to aid behaviour change and food choice. For example, an increasing array of products are now pack marked as vegan. The participants will be asked to keep their diet similar to their original and the Registered Dietitian involved in this study will plan their weekly menus accordingly.
Other: Adoption of a vegan diet
Adoption of a vegan diet The participants of this study wil be asked to adopt a vegan diet under the supervision of a Registered Dietitian.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change from Baseline TMAO plasma levels at 1, 8 and 12 weeks.
Time Frame: at 1 (+ 5 days) week , 8 (+/- 5 days) weeks and 12 weeks (+/- 5 days)
urine and plasma samples for TMAO (μM)
at 1 (+ 5 days) week , 8 (+/- 5 days) weeks and 12 weeks (+/- 5 days)
Change from Baseline 3-hour post-challenge glucose levels at 1, 8 and 12 weeks.
Time Frame: at 1 (+ 5 days) week , 8 (+/- 5 days) weeks and 12 weeks (+/- 5 days)
blood samples (mmol/l)
at 1 (+ 5 days) week , 8 (+/- 5 days) weeks and 12 weeks (+/- 5 days)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
TMAO (μM) urine levels at baseline.
Time Frame: at baseline
urine samples
at baseline
Change from Baseline in TMAO urine/plasma levels at 1 week following a vegan diet.
Time Frame: at 1 week (+ 5 days)
urine and plasma samples; TMAO (μM)
at 1 week (+ 5 days)
Change from Baseline 3-hour post-challenge glucose levels at 1 week following a vegan diet.
Time Frame: at 1 week (+ 5 days)
blood samples for glucose (mmol/l)
at 1 week (+ 5 days)
Change from week 8 in TMAO urine/plasma levels at 4 weeks after diet has returned to normal (week 12).
Time Frame: at 12 weeks (+/- 5 days)
urine and plasma samples for TMAO (μM)
at 12 weeks (+/- 5 days)
Change from week 8 in 3-hour post-challenge glucose levels at 4 weeks after diet has returned to normal (week 12).
Time Frame: at 12 weeks (+/- 5 days)
blood samples for glucose (mmol/l)
at 12 weeks (+/- 5 days)
Change from Baseline in body composition using dual energy X-ray absorptiometry (DXA) scan at 8 weeks following a vegan diet.
Time Frame: at baseline and week 8 (+/- 5 days)
DXA Scan
at baseline and week 8 (+/- 5 days)
Change from Baseline in biochemical measures of cardiometabolic health including post-challenge insulin at 1 week.
Time Frame: 1 week (+5 days)
blood samples (mmol/l)
1 week (+5 days)
Change from Baseline in biochemical measures of cardiometabolic health including post-challenge insulin at 8 weeks.
Time Frame: 8 weeks (+/- 5 days)
blood samples (mmol/l)
8 weeks (+/- 5 days)
Change from Baseline in biochemical measures of cardiometabolic health including post-challenge insulin at 12 weeks.
Time Frame: 12 weeks (+/- 5 days)
blood samples (mmol/l)
12 weeks (+/- 5 days)
Change from Baseline in biochemical measures of cardiometabolic health including fasting lipids and at 1 week.
Time Frame: 1 week (+5 days)
blood samples (mmol/l)
1 week (+5 days)
Change from Baseline in biochemical measures of cardiometabolic health including fasting lipids and inflammatory markers at 8 weeks.
Time Frame: 8 weeks (+/- 5 days)
blood samples (mmol/l)
8 weeks (+/- 5 days)
Change from Baseline in biochemical measures of cardiometabolic health including fasting lipids at 12 weeks.
Time Frame: 12 weeks (+/- 5 days)
blood samples (mmol/l)
12 weeks (+/- 5 days)
Change from Baseline in biochemical measures of cardiometabolic health including inflammatory markers at 1 week.
Time Frame: 1 week (+5 days)
blood samples (mmol/l)
1 week (+5 days)
Change from Baseline in biochemical measures of cardiometabolic health including inflammatory markers at 8 weeks.
Time Frame: 8 weeks (+/- 5 days)
blood samples (mmol/l)
8 weeks (+/- 5 days)
Change from Baseline in biochemical measures of cardiometabolic health including inflammatory markers at 12 weeks.
Time Frame: 12 weeks (+/- 5 days)
blood samples (mmol/l)
12 weeks (+/- 5 days)
The extent to which changes in the primary outcomes are mediated by, or independent of, changes to body composition.
Time Frame: baseline
DXA scan
baseline
The extent to which changes in the primary outcomes are mediated by, or independent of, changes to body composition.
Time Frame: week 8 (+/- 5 days)
DXA scan
week 8 (+/- 5 days)
The extent to which changes in the primary outcomes are mediated by, or independent of, changes to lifestyle factors.
Time Frame: baseline
3-day diet diaries
baseline
The extent to which changes in the primary outcomes are mediated by, or independent of, changes to lifestyle factors.
Time Frame: counselling visit (+5 days)
3-day diet diaries
counselling visit (+5 days)
The extent to which changes in the primary outcomes are mediated by, or independent of, changes to lifestyle factors.
Time Frame: week 1 (+5 days)
3-day diet diaries
week 1 (+5 days)
The extent to which changes in the primary outcomes are mediated by, or independent of, changes to lifestyle factors.
Time Frame: week 8 (+/- 5 days)
3-day diet diaries
week 8 (+/- 5 days)
The extent to which changes in the primary outcomes are mediated by, or independent of, changes to lifestyle factors.
Time Frame: week 12 (+/- 5 days)
3-day diet diaries
week 12 (+/- 5 days)
The extent to which changes in the primary outcomes are mediated by, or independent of, changes to lifestyle factors.
Time Frame: weeks 1-12
accelerometers
weeks 1-12
Semi-structured interviews with the completers, at the end of the study, to investigate perception responses having been on a vegan diet.
Time Frame: at week 12 (+/- 5 days)
semi-structured interviews
at week 12 (+/- 5 days)

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Leicester

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
University Hospitals, Leicester

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.

General Publications

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 4, 2017

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 7, 2019

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 7, 2019

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 4, 2017

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 16, 2017

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 20, 2017

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 30, 2020

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 29, 2020

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2018

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 0625

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

IPD Plan Description

There is no plan to make individual participant data (IPD) available to other researchers.

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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