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

Study Overview
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Brief Summary
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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).

Official Title
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Effect of the Sustainable Diet on Gut Microbiota and the Metabolome: a Randomised Crossover Study

Conditions
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Microbiota, Nutrition, Healthy

Intervention / Treatment
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* Other: Plant-based diet
* Other: Western diet


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Cross-over single-blinded
Masking: Single


Arms and Interventions

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

What is the study measuring?
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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 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Plant-based diet, Western diet, Gut microbiota,, Trimethylamine N-oxide, Human intervention study.