Gut Health Enhancement by Eating Favourable Food

NCT05900609 | Completed

• 1 other identifier: NL83652.028.23
• Study Type: interventional
• Target: 146
• Locations: 1 country
• Sites: 1

Brief Summary

Within the GEEF om je buik study the effects of an 8-week intervention with either a diet rich in fiber or fermented food on the gut microbiota will be investigated.

Conditions

Microbial Colonization

Keywords

Fiber; Fermented food; Immune system; Microbiota

Outcome Measures

Primary Outcomes (3)

• Microbiota diversity

  Microbial richness (ASV) using 16s rRNA

  Baseline (week 0)

• Microbiota diversity

  Microbial richness (ASV) using 16s rRNA

  End ramp-up (week 2)

• Microbiota diversity

  Microbial richness (ASV) using 16s rRNA

  End intervention (week 8)

Secondary Outcomes (61)

• Gut microbiota composition

  Baseline (week 0)

• Gut microbiota composition

  End ramp-up (week 2)

• Gut microbiota composition

  End intervention (week 8)

• Carbohydrate Active Enzymes (CAZymes)

  Baseline (week 0)

• Carbohydrate Active Enzymes (CAZymes)

  End ramp-up (week 2)

Other Outcomes (4)

• Body Mass Index (BMI)

  Baseline (week 0)

• Body Mass Index (BMI)

  End ramp-up (week 2)

• Body Mass Index (BMI)

  End intervention (week 8)

Study Arms (3)

Fiber arm

EXPERIMENTAL

Subjects receive dietary guidelines, to increase their fiber intake. Additionally, during the last 6 weeks of the intervention period subjects receive a study product containing 8,5 grams fiber per day. Additionally, subjects receive general guidelines about the effect of nutrition on the gut microbiome.

Dietary Supplement: WholeFiber

Fermented food arm

EXPERIMENTAL

Subjects receive dietary guidelines, to increase their intake of fermented foods. Additionally, during the last 6 weeks of the intervention period subjects receive a study product of 17 millilitres concentrated kombucha per day. Additionally, subjects receive general guidelines about the effect of nutrition on the gut microbiome.

Dietary Supplement: Kombucha

Control

PLACEBO COMPARATOR

Subjects receive general guidelines about the effect of nutrition on the gut microbiome. Additionally, during the last 6 weeks of the intervention period subjects receive a placebo product of 10 grams maltodextrin per day.

Dietary Supplement: Maltodextrin DE19/21

Interventions

WholeFiber DIETARY_SUPPLEMENT

WholeFiberTM is a product with high levels of prebiotic dietary fibers (\~85%) mainly consisting of inulin, and some pectin, hemi-cellulose and cellulose that is derived from the root vegetable, chicory roots. Fiber guidelines: Subjects receive a booklet with recipes high in fiber. Subjects are recommended to use 2 recipes + 2 snacks per day. Estimated average intake via the recipes in the recipe booklet is 24 grams/day. General guidelines on nutrition and microbiome: Subjects receive a link to a website with general recommendations to positively alter the gut microbiome (website Voedingscentrum and Dutch Digestive Foundation).

Also known as: Chicory roots

Fiber arm

Kombucha DIETARY_SUPPLEMENT

The kombucha is produced by a minimum three-month long fermentation process. It is a live fermented herbal drink essence, without refined sugar, and an unpasteurized, organic product. Fermented food guidelines: Study participants in the fermented foods arm are asked to use 3 additional servings of fermented food per day, using the fermented food list / recipe booklet. General guidelines on nutrition and microbiome: Subjects receive a link to a website with general recommendations to positively alter the gut microbiome (website Voedingscentrum and Dutch Digestive Foundation).

Also known as: Fermented tea

Fermented food arm

Maltodextrin DE19/21 DIETARY_SUPPLEMENT

Maltodextrin DE19/21 is a digestible carbohydrate, that is completely digested and does not reach the colon, which makes it a suitable placebo dietary compound and the reason why it is frequently used in comparable studies. General guidelines on nutrition and microbiome: Subjects receive a link to a website with general recommendations to positively alter the gut microbiome (website Voedingscentrum and Dutch Digestive Foundation).

Control

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Men and Women, aged ≥18 - ≤70 years;
• Being able to read and speak Dutch;
• Willing to keep a stable dietary pattern throughout the study, apart from the dietary advice in the study;
• Having a smartphone compatible with the Lifedata or PocketQ app to fill out the daily questionnaires.

You may not qualify if:

• Having a disease or medical condition which can influence the study results such as diabetes, cancer, diagnosed irritable bowel syndrome, renal disease, liver enzyme abnormality, malignant neoplasm, or a history of inflammatory diseases (such as multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease);
• Having a history of intestinal surgery that might interfere with study outcomes (this does not include an appendectomy or cholecystectomy);
• Average dietary fiber intake of ≥18 gram (women) or ≥22 gram (men) per day, according to the fiber screen questionnaire (see F1 questionnaires);
• More than 3 servings of fermented foods per day as assessed with the fermented food frequency questionnaire (see F1 questionnaires);
• Having a Body Mass Index (BMI) of ≥ 30 kg/m2 (self-reported);
• Currently following a strict diet and unwilling or unable to change; for example, a gluten free diet or a "crash diet" using meal substitutes;
• Specific food allergies that interfere with dietary intervention (for example, gluten, lactose, etc);
• Use of prebiotics, probiotics and/or synbiotics (this should be stopped 4 weeks before the start of the study) and use of fiber supplements;
• Use of antibiotic treatment less than 3 months before start of the study and/or use of antibiotics during the study;
• Use of medication that can interfere with the study outcomes, as judged by the medical supervisor;
• Alcoholic use of ≥14 (women) or ≥28 (men) glasses of alcoholic beverages per week;
• Use of soft or hard drugs (should be stopped at least 4 weeks before start of the study);
• Being pregnant or lactating;
• Participation in another clinical trial at the same time;
• Student or employee working at either Food, Health and Consumer Research from Wageningen Food and Biobased Research, Microbiology at VU, the MLDS, at WholeFiber, Keep Food Simple or at Cidrani;

Sponsors & Collaborators

• VU University of Amsterdam: lead
• Wageningen University and Research: collaborator
• Maag Lever Darm Stichting: collaborator
• Cidrani: collaborator
• WholeFiber: collaborator
• Keep Food Simple: collaborator

Study Sites (1)

Stichting Wageningen Research

Wageningen, Gelderland, 6708 WG, Netherlands

Location

Related Publications (4)

• Wastyk HC, Fragiadakis GK, Perelman D, Dahan D, Merrill BD, Yu FB, Topf M, Gonzalez CG, Van Treuren W, Han S, Robinson JL, Elias JE, Sonnenburg ED, Gardner CD, Sonnenburg JL. Gut-microbiota-targeted diets modulate human immune status. Cell. 2021 Aug 5;184(16):4137-4153.e14. doi: 10.1016/j.cell.2021.06.019. Epub 2021 Jul 12.

  PMID: 34256014 BACKGROUND

• David LA, Maurice CF, Carmody RN, Gootenberg DB, Button JE, Wolfe BE, Ling AV, Devlin AS, Varma Y, Fischbach MA, Biddinger SB, Dutton RJ, Turnbaugh PJ. Diet rapidly and reproducibly alters the human gut microbiome. Nature. 2014 Jan 23;505(7484):559-63. doi: 10.1038/nature12820. Epub 2013 Dec 11.

  PMID: 24336217 BACKGROUND

• Myhrstad MCW, Tunsjo H, Charnock C, Telle-Hansen VH. Dietary Fiber, Gut Microbiota, and Metabolic Regulation-Current Status in Human Randomized Trials. Nutrients. 2020 Mar 23;12(3):859. doi: 10.3390/nu12030859.

  PMID: 32210176 BACKGROUND

• Stiemsma LT, Nakamura RE, Nguyen JG, Michels KB. Does Consumption of Fermented Foods Modify the Human Gut Microbiota? J Nutr. 2020 Jul 1;150(7):1680-1692. doi: 10.1093/jn/nxaa077.

  PMID: 32232406 BACKGROUND

MeSH Terms

Conditions

Communicable Diseases

Interventions

Kombucha Tea

Condition Hierarchy (Ancestors)

Infections; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Tea; Plant Preparations; Biological Products; Complex Mixtures; Fermented Beverages; Beverages; Diet, Food, and Nutrition; Physiological Phenomena; Fermented Foods; Food and Beverages

Study Officials

• Nicole de Wit, PhD

  Wageningen Food and Biobased Research

  PRINCIPAL INVESTIGATOR

• Remco Kort, PhD

  VU University of Amsterdam

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: This study is partially blinded, study participants in the fiber and fermented group will be informed about their intervention after randomization. However, the control group will remain blind throughout the intervention period. Furthermore, participants are not made aware of the different types of intervention before start or during the intervention period. This is done to prevent any adjustments of their diets based on the advices in the other groups and to ensure that the control group stays blinded.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor doctor

Model Details: The study applies a randomized, parallel design of 8 weeks (+ follow-up after 3 months)

Study Record Dates

• First Submitted: April 3, 2023
• First Posted: June 12, 2023
• Study Start: May 22, 2023
• Primary Completion: November 26, 2023
• Study Completion: March 6, 2024
• Last Updated: July 8, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

NL (1)