Gut Health Enhancement by Eating Favourable Food

NCT ID: NCT05900609

Last Updated: 2025-07-08

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 146 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-05-22
• Study Completion Date: 2024-03-06

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.

Detailed Description

This study is a randomized controlled trial (RCT) with three intervention groups (high dietary fiber group (HDF), high fermented foods group (HFF), and a control group (CG)). The total duration of the study is 5 months and consists of an 8-week intervention (2-week ramp up period with dietary guidelines, followed by 6-week period with dietary guidelines + additional consumption of study products) and a follow-up after 3 months. In total 147 subjects will be included.

Conditions

Microbial Colonization

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: NONE

Study Groups

Fiber arm

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.

Group Type: EXPERIMENTAL

WholeFiber

Intervention Type: 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).

Fermented food arm

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.

Group Type: EXPERIMENTAL

Kombucha

Intervention Type: 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).

Control

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.

Group Type: PLACEBO_COMPARATOR

Maltodextrin DE19/21

Intervention Type: 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).

Interventions

WholeFiber

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).

Intervention Type: DIETARY_SUPPLEMENT

Kombucha

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).

Intervention Type: DIETARY_SUPPLEMENT

Maltodextrin DE19/21

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).

Intervention Type: DIETARY_SUPPLEMENT

Other Intervention Names

Chicory roots; Fermented tea

Eligibility Criteria

Inclusion Criteria

• 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.

Exclusion Criteria

• 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;
• Unable to follow or comply to study rules.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 70 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Wageningen University and Research

OTHER

Sponsor Role: collaborator

Maag Lever Darm Stichting

OTHER

Sponsor Role: collaborator

Cidrani

UNKNOWN

Sponsor Role: collaborator

WholeFiber

UNKNOWN

Sponsor Role: collaborator

Keep Food Simple

UNKNOWN

Sponsor Role: collaborator

VU University of Amsterdam

OTHER

Sponsor Role: lead

Responsible Party

Remco Kort

Professor doctor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Nicole de Wit, PhD

Role: PRINCIPAL_INVESTIGATOR

Wageningen Food and Biobased Research

Remco Kort, PhD

Role: PRINCIPAL_INVESTIGATOR

VU University of Amsterdam

Locations

Stichting Wageningen Research

Wageningen, Gelderland, Netherlands

Countries

Netherlands

References

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.

Reference Type: BACKGROUND

PMID: 34256014 (View on PubMed)

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.

Reference Type: BACKGROUND

PMID: 24336217 (View on PubMed)

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.

Reference Type: BACKGROUND

PMID: 32210176 (View on PubMed)

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.

Reference Type: BACKGROUND

PMID: 32232406 (View on PubMed)

Other Identifiers

NL83652.028.23

Identifier Type: -

Identifier Source: org_study_id