Effect of the Sustainable Diet on Gut Microbiota and the Metabolome: a Randomised Crossover Study (SUSUGUT)

Unhealthy diets are closely linked to non-communicable diseases and constitute higher risk of morbidity and mortality than unsafe sex, alcohol, tobacco and drugs use combined. According to the World Health Organization (WHO), a healthy diet follows a plant-based pattern with low quantities of red meat and a low simple sugar intake. It would also reduce anthropological ecologic impact. We hypothesize that a plant-based diet will beneficially modify the gut microbiota and metabolome, influencing also Trimethylamine N-oxide (TMAO), a metabolite associated to CVD.

This study has a randomized single blind crossover design that compares a plant-based diet towards a control western diet. It is applied to volunteers aged 18-70 years, N=20. Each dietary intervention (plant-based and western) would last for 16 consecutive days separated by a minimum of 7 weeks washout period (intervention 1-washout-intervention 2). Samples of blood urine and faeces will be collected at day 1 and 14 of each intervention. On day 14 will be performed L-carnitine challenge with 1200mg of L-carnitine to test the levels of TMAO), in for the next 2 consecutive days (24h and 48h post treatment).

Study Overview

• Status: Completed
• Conditions: Microbiota; Nutrition, Healthy
• Intervention / Treatment: Other: Plant-based diet; Other: Western diet

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Londonderry
    • Coleraine, Londonderry, United Kingdom, BT52 1SA
      • Human Intervention Studies Unit, Ulster University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Free-living, apparently healthy adults
• Bmi>18
• Aged 18-70 years at recruitment
• Non-smokers

Exclusion criteria:

• Non-free-living adults
• Adults <18 or >70 years at recruitment
• BMI<18
• Current smokers

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental: Plant-based diet; Diet rich in fruit and vegetables (42% carbohydrates, 17.2% fibres; 15% proteins and 43% fats).	Other: Plant-based diet; 16 days with all foods provided
Active Comparator: Active Comparator: Western diet; Diet Rich in Processed Foods (48% carbohydrates, 10.4% fibres; 14% proteins and 39% fats).	Other: Western diet; 16 days with all foods provided

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Gut microbiota changes	Significant changes in the number of bifidobacteria	Change over 14 days
Quantification of Trimethylamine N-oxide	Changes in response to L-Carnitine challenge	Day 16

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Bioactivity of faecal water	Measured by using faecal water as basis for growth media (ex vivo measure)	Change over 14 days
Effects on inflammatory markers of both diets	Cytokine analysis via ELISA test (MagPix)	Change over 14 days
Ex vivo effects of faecal water on gut pathobionts	Co-culturing the aqueous phase of faeces with C. difficile to assess changes in its biology	Day 14
Quantification of phytochemicals	Measured by LC-MS	Change over 14 days
Quantification of Short Chain Fatty Acids (SCFA)	Measured by nuclear magnetic resonance (NMR)	Change over 14 days

Collaborators and Investigators

• Sponsor: University of Ulster
• Collaborators: Fondazione Edmund Mach

Study record dates

Study Major Dates

• Study Start (Actual): July 2, 2021
• Primary Completion (Actual): December 17, 2021
• Study Completion (Actual): December 17, 2021

Study Registration Dates

• First Submitted: January 28, 2022
• First Submitted That Met QC Criteria: January 28, 2022
• First Posted (Actual): February 9, 2022

Study Record Updates

• Last Update Posted (Actual): February 9, 2022
• Last Update Submitted That Met QC Criteria: January 28, 2022
• Last Verified: January 1, 2022

More Information

Terms related to this study

• Keywords: Plant-based diet; Western diet; Gut microbiota,; Trimethylamine N-oxide; Human intervention study.
• Other Study ID Numbers: REC/20/0008

Drug and device information, study documents

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