Luxembourgish Fiber Cohort

Summary

Many human populations across the world are deficient in the intake of dietary fiber. This decline in fiber consumption parallels an increase in prevalence of a multitude of diseases (e.g. colorectal cancer, multiple sclerosis). A possible link for this association between dietary changes and the diseases could rest in the trillions of commensal gut microbes that digest dietary fibers, provide energy for colonic cells, and modulate the immune system. However, the molecular mechanisms that link fiber deficiency via the activities of the gut microbiome to various diseases have been poorly understood. The investigators previously showed that, in a mouse model with a defined human gut microbiota, removal of fiber from the diet favors proliferation of bacteria that degrade the gut's protective mucus lining. In the proposed project, the investigators aim to translate our findings from mouse studies to humans using a 2x2 crossover study among healthy adults. Forty participants will be randomly assigned to a low- or high-fiber dietary intervention and then, following a washout period to reverse any changes, switched to the other diet type. By employing longitudinal sampling of stool collections, the investigators envision that participants will exhibit increased abundance and activities of mucolytic bacteria when fed a low-fiber diet. The unique selling point of the proposed study involves setting up high-throughput culture collections of mucus-degrading bacteria, whose abundances and activities will be investigated by sequencing and enzymatic assays in stool. Additionally, the investigators will measure inflammatory markers in blood using CyTOF to assess whether short-term fiber deficiency exerts detectable changes in the host immune function. Thus, the proposed dietary intervention clinical trial will help elucidate the role of fiber deficiency in various chronic diseases.

Conditions

• Dietary Fiber
• Gastrointestinal Microbiome
• Healthy Volunteers

Interventions

DIETARY_SUPPLEMENT

High Fiber Diet Intervention

Plant-based diet with a targeted quantity of 35 g of dietary fiber per day, from a variety of fiber types. Each meal will be balanced to provide all essential nutrients and portions will be of adequate size to ensure participants are satiated. Participants on both diet interventions will be given multivitamin supplements in order to ensure they are receiving essential vitamins and minerals.

DIETARY_SUPPLEMENT

Low Fiber Diet Intervention

Animal based diet (meat, dairy) with a targeted quantity of 10 g of dietary fiber per day. Each meal will be balanced to provide all essential nutrients and portions will be of adequate size to ensure participants are satiated. Participants on both diet interventions will be given multivitamin supplements in order to ensure they are receiving essential vitamins and minerals.

Sponsors & Collaborators

• Centre Hospitalier du Luxembourg

  collaborator OTHER

• Integrated Biobank of Luxembourg

  collaborator OTHER

• University of Luxembourg

  collaborator OTHER

• Luxembourg Institute of Health

  lead OTHER_GOV

Principal Investigators

• Mahesh S Desai, PhD · Luxembourg Institute of Health

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

55 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2021-02-22

Primary Completion

2022-12-05

Completion

2022-12-05

Countries

• Luxembourg

Study Locations