How Differences in the Composition of Microorganisms in the Soil Affect the Microorganisms in the Human Gut, Through the Vegetables That Grow in it: a Process Pilot Study With Healthy Participants (HUMANITAS)
29 juli 2026 bijgewerkt door: Pieter Maljaars, Leiden University Medical Center
The Effect of Soil Biodiversity on Human Gut Microbiome: a Process Pilot Study (The HUMANITAS Study)
There are two objectives for this clinical trial.
The first is to test whether, with the current logistics and study setup it is possible to perform the study well and see where there might be bottlenecks we couldn't predict.
The second objective is to investigate the relation between the composition of the microorganisms in the soil, the crops that grow in that soil, and the human gut.
During the study participants will drink three vegetable smoothies a day, for two periods of one week.
The only difference between the two periods is whether the vegetables come from a farm with a low diversity of microorganisms in the soil or a high diversity.
Participants will be asked to give blood samples and turn in fecal samples before and after each period.
Studie Overzicht
Toestand
Nog niet aan het werven
Conditie
Interventie / Behandeling
Gedetailleerde beschrijving
This randomized, double-blind, crossover pilot study will be used to assess the feasibility of logistics including vegetable delivery and preparation of the intervention product by the participants themselves. Besides feasibility, we will aim to identify live bacteria and fungi present in the intervention product (smoothies) and trace these back in stool samples.
The gut microbiome is also called the "second genome" to which many protective and life-supporting functions have been externalized. It orchestrates the crosstalk between our own cells and environmental metagenome. Diet and food choices can modulate gut microbiome species and functional diversity, but the mechanisms by which this occurs are unclear. The nutritional quality of crops, the crop microbiome and the soil microbiome may therefore all be involved.
Ten participants will be randomized in a cross-over design, with each participant drinking three 150 mL vegetable smoothies per day for two separate intervention weeks (HiDi vs LoDi soil origin, randomized 1 : 1). During the first week, smoothies will be prepared with the vegetables derived from microbiome-enriched soil (HiDi) or microbiome-impoverished soil (LoDi). Vegetables, a blender, and detailed instructions to prepare the smoothies on-site will be delivered to the participant. Each participant is asked to keep a diary (in the form of a daily Castor questionnaire), with special attention to dietary habits and intake. Furthermore, before and after this specified diet week, blood and stool samples will be collected. After a washout period of two weeks, participants will be offered identical meals in a crossover design.
Studietype
Ingrijpend
Inschrijving (Geschat)
10
Fase
- Niet toepasbaar
Contacten en locaties
In dit gedeelte vindt u de contactgegevens van degenen die het onderzoek uitvoeren en informatie over waar dit onderzoek wordt uitgevoerd.
Studiecontact
- Naam: Jeroen Maljaars, MD, PhD
- Telefoonnummer: +31 71 526 3575
- E-mail: P.W.J.Maljaars@lumc.nl
Studie Contact Back-up
- Naam: Maarten Tushuizen, MD, PhD
- Telefoonnummer: +31 71 526 9111
- E-mail: M.E.Tushuizen@lumc.nl
Studie Locaties
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South Holland
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Leiden, South Holland, Nederland, 2333ZA
- Leids Universitair Medisch Centrum
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Contact:
- Jeroen Maljaars, MD, PhD
- Telefoonnummer: +31 71 526 9111
- E-mail: P.W.J.Maljaars@lumc.nl
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Hoofdonderzoeker:
- Jeroen Maljaars, MD, PhD
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Deelname Criteria
Onderzoekers zoeken naar mensen die aan een bepaalde beschrijving voldoen, de zogenaamde geschiktheidscriteria. Enkele voorbeelden van deze criteria zijn iemands algemene gezondheidstoestand of eerdere behandelingen.
Geschiktheidscriteria
Leeftijden die in aanmerking komen voor studie
- Volwassen
- Oudere volwassene
Accepteert gezonde vrijwilligers
Ja
Beschrijving
Inclusion Criteria:
- Aged 18 to 70 years
- Written informed consent
- Inhabitant of Leiden
Exclusion Criteria:
- Any documented causes of chronic disease
- Suspicion of or present excessive alcohol use defined as >2 units/day (>14/week)
- Recent use (<3 months) of antibiotics
- Any known food allergy or restriction, or following a vegan/vegetarian diet
- Use of possible drugs interfering microbiota or recent (< 3 months) changes in dosages
- A psychiatric, addictive or any other disorder that compromises the participants ability to understand the study content and to give written informed consent for participation in the study
Studie plan
Dit gedeelte bevat details van het studieplan, inclusief hoe de studie is opgezet en wat de studie meet.
Hoe is de studie opgezet?
Ontwerpdetails
- Primair doel: Preventie
- Toewijzing: Gerandomiseerd
- Interventioneel model: Crossover-opdracht
- Masker: Verdrievoudigen
Wapens en interventies
Deelnemersgroep / Arm |
Interventie / Behandeling |
|---|---|
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Actieve vergelijker: Crops derived from Low followed by High diversity soil
Participants will be given vegetables, originating from low- or high-microbial diversity soil, to prepare smoothies with.
In this arm participants start with vegetables from a low diversity soil, after a washout period of two weeks they will receive vegetables from a high diversity soil.
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Vegetable smoothie prepared with crops grown in low-microbial diversity soil
Vegetable smoothie prepared with crops grown in high-microbial diversity soil
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Actieve vergelijker: Crops derived from High followed by Low diversity soil
Participants will be given vegetables, originating from low- or high-microbial diversity soil, to prepare smoothies with.
In this arm participants start with vegetables from a high diversity soil, after a washout period of two weeks they will receive vegetables from a low diversity soil.
|
Vegetable smoothie prepared with crops grown in low-microbial diversity soil
Vegetable smoothie prepared with crops grown in high-microbial diversity soil
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Wat meet het onderzoek?
Primaire uitkomstmaten
Uitkomstmaat |
Maatregel Beschrijving |
Tijdsspanne |
|---|---|---|
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Feasibility of logistics of the study protocol: Deliveries
Tijdsspanne: From start enrollment to the end of treatment at 4 weeks
|
The percentage of successful deliveries to the participants in the pre-agreed time window.
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From start enrollment to the end of treatment at 4 weeks
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Feasibility of logistics of the study protocol: Preparation of the intervention product
Tijdsspanne: From the start of the treatment period until the end at 4 weeks
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Using the Daily diary (Castor questionnaire), successful preparation of the intervention product is assessed.
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From the start of the treatment period until the end at 4 weeks
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Feasibility of logistics of the study protocol: Recruitment rate
Tijdsspanne: From the start of recruitment until the start of the study
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Number of recruited participants per month until the start of the study.
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From the start of recruitment until the start of the study
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Tracing back life microorganisms from the smoothie in stool samples
Tijdsspanne: Day 1, Day 7, Day 22, and Day 28
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Life bacteria present in the smoothies will be cultured and sequenced to then compare to feces samples of participants
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Day 1, Day 7, Day 22, and Day 28
|
Secundaire uitkomstmaten
Uitkomstmaat |
Maatregel Beschrijving |
Tijdsspanne |
|---|---|---|
|
Participant compliance to the study protocol
Tijdsspanne: From start enrolment until the end of treatment at the end of 4 weeks
|
Compliance with the protocol will be assessed through the daily lifestyle diary (in the form of a Castor questionnaire).
Which will capture the number of consumed smoothies (≥95.2%) and number of consumed smoothies at the correct time window (≥80%).
As well whether the duration and time of exercise (≥80%), duration and time of nighttime sleeping period (≥80%), timing and content of main meals (≥80%) between the two periods are comparable.
For each of the parameters the compliance threshold is indicated above.
Based on these parameters we will get a percentage of participants that were compliant.
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From start enrolment until the end of treatment at the end of 4 weeks
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Shifts in gut microbiome composition
Tijdsspanne: Baseline, Day 8, Day 21, and Day 29
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Metagenomics will be performed on feces samples from participants to get an compositional view of the gut microbiome.
Samples will be taken at baseline, Day 8, Day 21, and Day 29
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Baseline, Day 8, Day 21, and Day 29
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Sample completeness
Tijdsspanne: From start of treatment to the end of treatment at 4 weeks
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percentage of complete sampling sets
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From start of treatment to the end of treatment at 4 weeks
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Asses willingness of participants to create their own intervention product
Tijdsspanne: From start treatment to end of treatment at 4 weeks
|
Using the Daily diary (Castor questionnaire), the participants are required to fill in their opinion on creating their own intervention product on a daily basis.
This is measured on a 10 point scale, with 1 being equal to never wanting to do it again and 10 being equal to enjoying it.
There is also an optional open question where participants can justify their answer.
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From start treatment to end of treatment at 4 weeks
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Differences in phytonutrient levels in serum
Tijdsspanne: Baseline, Day 8, Day 21, and Day 29
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After confirmation of significant changes in gut microbiome composition, phytonutrient levels will be measured in serum.
Serum will be collected at Baseline, Day 8, Day 21, and Day 29
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Baseline, Day 8, Day 21, and Day 29
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Medewerkers en onderzoekers
Hier vindt u mensen en organisaties die betrokken zijn bij dit onderzoek.
Sponsor
Medewerkers
Publicaties en nuttige links
De persoon die verantwoordelijk is voor het invoeren van informatie over het onderzoek stelt deze publicaties vrijwillig ter beschikking. Dit kan gaan over alles wat met het onderzoek te maken heeft.
Algemene publicaties
- 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.
- Albenberg LG, Wu GD. Diet and the intestinal microbiome: associations, functions, and implications for health and disease. Gastroenterology. 2014 May;146(6):1564-72. doi: 10.1053/j.gastro.2014.01.058. Epub 2014 Feb 4.
- Henao-Mejia J, Elinav E, Jin C, Hao L, Mehal WZ, Strowig T, Thaiss CA, Kau AL, Eisenbarth SC, Jurczak MJ, Camporez JP, Shulman GI, Gordon JI, Hoffman HM, Flavell RA. Inflammasome-mediated dysbiosis regulates progression of NAFLD and obesity. Nature. 2012 Feb 1;482(7384):179-85. doi: 10.1038/nature10809.
- Clemente JC, Ursell LK, Parfrey LW, Knight R. The impact of the gut microbiota on human health: an integrative view. Cell. 2012 Mar 16;148(6):1258-70. doi: 10.1016/j.cell.2012.01.035.
- Turnbaugh PJ, Backhed F, Fulton L, Gordon JI. Diet-induced obesity is linked to marked but reversible alterations in the mouse distal gut microbiome. Cell Host Microbe. 2008 Apr 17;3(4):213-23. doi: 10.1016/j.chom.2008.02.015.
- Julious, S.A. (2005), Sample size of 12 per group rule of thumb for a pilot study. Pharmaceut. Statist., 4: 287-291. https://doi.org/10.1002/pst.185
- Sanna S, van Zuydam NR, Mahajan A, Kurilshikov A, Vich Vila A, Vosa U, Mujagic Z, Masclee AAM, Jonkers DMAE, Oosting M, Joosten LAB, Netea MG, Franke L, Zhernakova A, Fu J, Wijmenga C, McCarthy MI. Causal relationships among the gut microbiome, short-chain fatty acids and metabolic diseases. Nat Genet. 2019 Apr;51(4):600-605. doi: 10.1038/s41588-019-0350-x. Epub 2019 Feb 18.
- Hirt H. Healthy soils for healthy plants for healthy humans: How beneficial microbes in the soil, food and gut are interconnected and how agriculture can contribute to human health. EMBO Rep. 2020 Aug 5;21(8):e51069. doi: 10.15252/embr.202051069. Epub 2020 Jul 31.
- Blum WEH, Zechmeister-Boltenstern S, Keiblinger KM. Does Soil Contribute to the Human Gut Microbiome? Microorganisms. 2019 Aug 23;7(9):287. doi: 10.3390/microorganisms7090287.
- Fierer N. Embracing the unknown: disentangling the complexities of the soil microbiome. Nat Rev Microbiol. 2017 Oct;15(10):579-590. doi: 10.1038/nrmicro.2017.87. Epub 2017 Aug 21.
- Leeming ER, Louca P, Gibson R, Menni C, Spector TD, Le Roy CI. The complexities of the diet-microbiome relationship: advances and perspectives. Genome Med. 2021 Jan 20;13(1):10. doi: 10.1186/s13073-020-00813-7.
- Johnson AJ, Zheng JJ, Kang JW, Saboe A, Knights D, Zivkovic AM. A Guide to Diet-Microbiome Study Design. Front Nutr. 2020 Jun 12;7:79. doi: 10.3389/fnut.2020.00079. eCollection 2020.
Studie record data
Deze datums volgen de voortgang van het onderzoeksdossier en de samenvatting van de ingediende resultaten bij ClinicalTrials.gov. Studieverslagen en gerapporteerde resultaten worden beoordeeld door de National Library of Medicine (NLM) om er zeker van te zijn dat ze voldoen aan specifieke kwaliteitscontrolenormen voordat ze op de openbare website worden geplaatst.
Bestudeer belangrijke data
Studie start (Geschat)
1 augustus 2026
Primaire voltooiing (Geschat)
1 september 2026
Studie voltooiing (Geschat)
1 september 2026
Studieregistratiedata
Eerst ingediend
16 juli 2026
Eerst ingediend dat voldeed aan de QC-criteria
29 juli 2026
Eerst geplaatst (Werkelijk)
3 augustus 2026
Updates van studierecords
Laatste update geplaatst (Werkelijk)
3 augustus 2026
Laatste update ingediend die voldeed aan QC-criteria
29 juli 2026
Laatst geverifieerd
1 juli 2026
Meer informatie
Termen gerelateerd aan deze studie
Trefwoorden
Andere studie-ID-nummers
- NL-010026
Plan Individuele Deelnemersgegevens (IPD)
Bent u van plan om gegevens van individuele deelnemers (IPD) te delen?
JA
Beschrijving IPD-plan
Metagenomic sequencing data from feces and pythonutrient levels in serum (if available)
IPD-tijdsbestek voor delen
Beginning 1 month after publication with no end date
IPD delen Ondersteunend informatietype
- LEERPROTOCOOL
- ANALYTIC_CODE
Informatie over medicijnen en apparaten, studiedocumenten
Bestudeert een door de Amerikaanse FDA gereguleerd geneesmiddel
Nee
Bestudeert een door de Amerikaanse FDA gereguleerd apparaatproduct
Nee
Deze informatie is zonder wijzigingen rechtstreeks van de website clinicaltrials.gov gehaald. Als u verzoeken heeft om uw onderzoeksgegevens te wijzigen, te verwijderen of bij te werken, neem dan contact op met register@clinicaltrials.gov. Zodra er een wijziging wordt doorgevoerd op clinicaltrials.gov, wordt deze ook automatisch bijgewerkt op onze website .