Capture of Healthy Gut Bacteria Associated to High Fiber Diet

Official title

In Silico and in Vitro Targeting of Healthy Gut Bacteria With Fiber Degrading Metabolic Potential

Overview

The role of the intestinal microbiota on health is now well recognised, and diet is one of the factors influencing the maintenance of a healthy intestinal microbiota. More specifically, the consumption of fruit, vegetables and cereals is associated with good health and, in particular, with an increase in the relative abundance of bacterial groups described as beneficial. To date, a large number of bacterial species in the intestinal microbiota have yet to be isolated and cultivated, which limits the characterisation of their potential health benefits. In order to isolate and cultivate these intestinal bacteria, it is particularly relevant to recruit individuals with a high-fibre diet.

Detailed description

Since two decades, numerous studies have been performed to better understand the role of the gut microbiota in health and disease. An imbalance in the intestinal microbiota, known as dysbiosis, is frequently described as a cause of many chronic diseases and metabolic dysfunctions in humans. Among the factors that play an important role in maintaining this balance, diet plays a predominant role. More specifically, the consumption of fruit, vegetables and cereals is associated with good health and, in particular, with an increase in the relative abundance of bacterial groups described as beneficial. Modulating the intestinal microbiota via the or directly by providing these beneficial bacteria (next generation probiotics NGPs) is therefore a possible promising approach for the prevention and/or treatment of pathologies. To date, a large number of bacterial species in the intestinal microbiota have yet to be isolated and cultivated, which limits the characterization of their potential health benefits. Having strains that can be isolated and cultured is an essential step in phenotyping and characterization. In order to isolate and cultivate these intestinal bacteria, it is particularly important to recruit individuals with a high-fiber diet. In this context, a positive selection of donors, based on their dietary profiles highly enriched in fiber, is essential. In this study, the aim is to identify in silico unprecedented potentially new beneficial gut bacteria, and isolate, culture and characterize these bacterial species for their potential. This will be an innovative approach, using culturomics tools guided by metagenomics to isolate them. To do this, the fecal samples of 10 healthy volunteers will be collected with a regular and diversified intake of fruit, vegetables and cereals, which encourage the growth of beneficial micro-organisms and increase the richness of the intestinal microbiota.

Primary outcome measures

• Isolation and culture of one isolate from each target species [Time frame: Up to 3 years]

Secondary outcome measures (4)

• metagenomic profiles in relation to dietary profiles [Time frame: Up to 3 years]
• growth capacity of the isolates [Time frame: Up to 3 years]
• Functional potential of the isolates [Time frame: up to 3 years.]
• Phenotypic caracterization of the isolates [Time frame: Up to 3 years]

Eligibility criteria

Inclusion criteria

• Healthy adult subjects ;
• Age between 20 and 50 (limits included) ;
• BMI between 18.5 and 25 kg/m2 (excluding limits) ;
• Consumption of more than 5 portions of fruit and vegetables a day;
• Intake of at least 25g of dietary fibre per day;
• A varied diet with little processed food.

Exclusion criteria

• Antibiotics and/or transit modulators taken in the 3 months prior to sampling;
• Known pathologies;
• Current treatment;
• History of digestive surgery having an impact on the microbiota, deemed incompatible with the study (bariatric surgery);
• Consumption of food supplements based on protein preparations, probiotics or prebiotics;
• Smoking (even occasionally);
• Alcohol consumption > 2 glasses (i.e. 20 g) per day;
• Intense sporting activity;
• Pregnant or breast-feeding women;
• Persons under legal protection (curatorship, guardianship, etc.);
• Volunteers taking part in another intervention study;
• Persons refusing to be registered on the French Ministry of Health's Fichier National des Volontaires Sains (National Register of Healthy Volunteers);
• Subject not affiliated to the social security system;
• Subject in a period of exclusion from a previous study or having received a total amount of compensation exceeding 6000 euros over the 12 consecutive months prior to the start of the trial (after verification in the Fichier des Volontaires pour la Recherche Biomédicale).

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Observational model

Cohort

Study locations

France · 1 center

• CRNH Auvergne — Clermont-Ferrand

Publications

• Caille A, Connan C, Lyon Belgy N, Borezee E, Cherbuy C, Meunier N, Meslier V. Positive nutritional selection of adults with healthy lifestyle and high daily fiber consumption for the isolation of beneficial intestinal bacteria: The iTARGET cohort study protocol. MethodsX. 2025 Mar 17;14:103268. doi: 10.1016/j.mex.2025.103268. eCollection 2025 Jun. PMID 40224142

Identifiers

NCT: NCT06166810 · 2023-A01677-38

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗