The Role of the Microbiome in the Response to Dietary Fibers Intake During Intermediate Fasting

The Role of the Microbiome and Host Physiology in Personalized Human Response to Dietary Fibers Intake During Intermediate Fasting

Dietary fibers are generally not degraded by the endogenous digestive enzymes, but rather by the complex ensemble of microorganisms that reside in the human gut [1]. This ensemble, collectively known as the human gut microbiome, plays a key role in breaking down, fermenting, and ultimately converting such dietary fibers into a variety of beneficial metabolites, including most notably, short chain fatty acids (SCFA). These end products of fibers' fermentation affect host metabolism, immunity, and physiology, and have been implicated in multiple diseases including obesity, metabolic syndrome, diabetes, and cardiovascular diseases.

Intermediate fasting, and in particular circadian intermediate fasting (i.e. 16 hours of fasting followed by 8 hours of allowed eating), has been shown to have positive associations with multiple health conditions as obesity, diabetes mellitus, cardiovascular disease, cancers, and neurologic disorders In this study, we will try to answer open questions utilizing the long fasting period during the day to investigate the isolated effect of dietary fiber consumption, uncovering the degradation effect, but not the bulking effect, on the microbiome and the host physiology, and in particular its glucose response.

Study Overview

• Status: Active, not recruiting
• Conditions: Dietary Fibers; Intermediate Fasting
• Intervention / Treatment: Dietary supplement: dietary fibers

Detailed Description

During the 22 days of the study, participants will wear a continuous glucose monitor, fill a daily food diary, and collect stool and oral samples which will be used for microbiota profiling. Participants will be asked to carry out an intermediate fasting regime, which will include: 16 straight hours of fasting followed by 8 hours which the participants will be allowed to eat. Drinking water is allowed throughout the fasting hours.

The groups will consume 4, 12, 20 grams of the dietary fiber per day, according to the group they were assigned to, while not exceeding the total fiber consumption of 50 grams per day, which is considered a high-fiber diet.

• Study Type: Interventional
• Enrollment (Actual): 115
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Israel
  • Rehovot, Israel
    • Weizmann Institute of Science

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

Male and Female BMI<28 Age - 18-70

Exclusion Criteria:

Consumption of antibiotics 3 months prior to the first day of the experiment. Consumption of probiotic or dietary fibers supplements 1 month prior to the first day of the experiment.

Practiced in intermediate fasting 1 month prior to the first day of the experiment.

Diagnosis with type 1 or type 2 diabetes. Pregnancy, breastfeeding, or fertility treatments in the last 6 months. Chronic disease (e.g. AIDS, Cushing syndrome, CKD, acromegaly, hyperthyroidism hepatitis, fibromyalgia, etc.).

Cancer and recent anticancer treatment. Psychiatric disorders. Coagulation disorders. IBD (inflammatory bowel diseases). IBS (Irritable bowel syndrome). Alcohol abuse, more than 2 drinks per day for males, and more than one drink for females.

Substance abuse. BMI>28. Daily dietary intake higher than 25 grams per day. History of abdominal surgeries (including Bariatric surgery). Mentally incompetent or lack of judgment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Fructo-oligosaccharide; Fructo-oligosaccharide 20g	Dietary supplement: dietary fibers; during days 13-22 the participants will consume the dietary fiber according to their randomization and continue fasting. Participants will be asked to collect stool and oral samples 4 times during this period.
Experimental: Arabinogalactan; Arabinogalactan 12g	Dietary supplement: dietary fibers; during days 13-22 the participants will consume the dietary fiber according to their randomization and continue fasting. Participants will be asked to collect stool and oral samples 4 times during this period.
Experimental: Glucomannan; Glucomannan 4g	Dietary supplement: dietary fibers; during days 13-22 the participants will consume the dietary fiber according to their randomization and continue fasting. Participants will be asked to collect stool and oral samples 4 times during this period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
microbiome	stool and oral samples	1 year
glycemic response of different dietary fibers	Continuous glucose monitoring (CGM)	1 year

Collaborators and Investigators

• Sponsor: Weizmann Institute of Science
• Collaborators: Hadassah Medical Organization
• Investigators: Principal Investigator: Eran Elinav, Prof, Weizmann Institute of Science

Study record dates

Study Major Dates

• Study Start (Actual): April 21, 2021
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): January 1, 2027

Study Registration Dates

• First Submitted: November 12, 2020
• First Submitted That Met QC Criteria: November 12, 2020
• First Posted (Actual): November 18, 2020

Study Record Updates

• Last Update Posted (Actual): March 19, 2026
• Last Update Submitted That Met QC Criteria: March 18, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Dietary Carbohydrates; Carbohydrates; Dietary Fiber
• Other Study ID Numbers: MHO-0488-20

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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