How do polyphenols, carotenoids and glucosinolates in our diets affect the diversity of our gut microbiome?

Not Applicable

• Conditions: utrition effects on gut microbiome; Nutritional, Metabolic, Endocrine

• Registration Number: ISRCTN14510401
• Lead Sponsor: Quadram Institute

Brief Summary

Not available

Detailed Description

Not available

Study Timeline

• Results First Posted: 1900-01-01
• Study Start: 2021-02-08
• Last Update Posted: 13 November 2023
• Study Completion: 2025-04-30

Recruitment & Eligibility

• Status: Ongoing
• Sex: All
• Target Recruitment: 27

Inclusion Criteria

1. Males and females aged 18 - 65 years old
2. BMI between 18.5 and 35 kg/m²
3. HbA1c below 42 mmol/mol
4. Access to a personal smart mobile phone enabled with near field communication (NFC) technology (this technology allows contactless card payments)
5. Living in an area which can receive a supermarket delivery

Exclusion Criteria

1. Smokers (or stopped smoking for less than 3 months)
2. Having diabetes, defined as HbA1c =48 mmol/mol or pre-diabetes, defined as HbA1c 42 – 47 mmol/mol
3. Prescribed and non-prescribed medications that may affect the outcome measures for this study e.g. statins, laxatives
4. Dietary supplements judged to affect the study data unless the participant is willing to discontinue them 4 weeks before the start of the study and for the duration of the study
5. Use of antibiotics in the 6 months prior to the study
6. Regular/recent use of colonic irrigation or other bowel cleansing techniques
7. Use of pre/probiotics or fermented foods such as Yakult, Kefir products, unless the participant is willing to discontinue use 4 weeks before the start of the study and for the duration of the study
8. Bowel movements =3 times per week
9. Gastrointestinal diseases (excluding hiatus hernia unless symptomatic or study intervention/procedure is contraindicated)
10. History of inflamed bowel (ulcerative colitis, Crohn’s disease or diverticulitis)
11. Immune-related conditions associated with altered microbiome – lupus, type 1 diabetes, multiple sclerosis, poorly controlled thyroid disorders (Greaves disease, Hashimoto’s disease), rheumatoid arthritis
12. Parallel participation in another research project
13. Unwillingness to adhere to the dietary guidelines for the study
14. Participation in another research project which has involved blood sampling within the last 4 months unless the total amount of combined blood from both studies does not exceed 470 ml
15. Has donated or intends to donate blood within 16 weeks prior to or during the study period
16. Any person related to or living with any member of the study team
17. Those who are part of the line management or supervisory structure of the Chief Investigator
18. Lack of capacity to provide written informed consent
19. Are pregnant or have been pregnant within the last 12 months
20. Participants following a vegetarian or vegan diet, as restrictions to bioactive-rich foods (fruits and vegetables) during the study may be too limiting
21. Clinical eligibility test results deemed by the CRF medical advisor to be indicative of a health problem which may compromise the well-being of the participant or which could affect the study outcome
22. Being susceptible to food allergies and intolerances
23. Active infection with COVID-19

Study & Design

• Study Type: Interventional
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
1. Gut microbiota diversity and composition and described by the Shannon index, a measure of alpha diversity. This will be measured at baseline and 2 weeks for each intervention<br>2. Adherence to diets based on self-reported logging in a dietary app throughout and compliance as measured by metabolite signatures in urine at baseline and 2 weeks for each intervention

Secondary Outcome Measures

Name	Time	Method
1. Gut microbial function through assessment of faecal metabolomics and total gene content of the microbiome of each host measured at baseline and 2 weeks for each intervention period<br>2. Urine metabolomics measured through liquid chromatography-mass spectrometry on 24-hour urine samples produced at baseline and 2 weeks of each intervention period<br>3. Vascular health as measured by blood pressure (in mmHg), blood levels of triglycerides and cholesterol (in mmol/L) at baseline and 2 weeks for each intervention period<br>4. Inflammation as measured by hsCRP (in mg/L) at baseline and 2 weeks for each intervention<br>5. Estimates of postprandial glycaemic metabolism measured by continuous glucose monitoring (measured in mmol/L) throughout both intervention periods, and glycaemic response to standardised meals at the end of each intervention period