The Effect of the Fermented Tea Beverage Kombucha on the Oral and Gut Microflora

Not Applicable

Completed

• Conditions: Microbial Colonization
• Interventions: Other: Consumption of heat-sterilized kombucha; Other: Consumption of kombucha

• Registration Number: NCT03873350
• Lead Sponsor: Lund University

Brief Summary

The purpose of the project is to investigate if consumption of the fermented tea beverage kombucha has an effect on the gut and/or oral microbiota, and further if it depends on the content of living bacteria or is inherent even to sterilized kombucha. This will be studied by a clinical trial in which healthy individuals will be given living kombucha, sterilized kombucha or water. The participants will consume one bottle (33 cl) of their designated drink per day for 21 days. Fecal and saliva samples will be collected before, directly and ten days after the intervention. These will then be examined to see if there is a change in the micro flora due to the kombucha.

Detailed Description

The first part of the project focuses on studying the characteristics of the kombucha drink and microbial composition. The amount of living organisms in the drink will be determined by colony count. Apart from this, the culture will be studied to determine which organisms are present and which are dominant. After isolation of colonies found from culturing, Sanger sequencing will be used for characterization.

The second part, which consists of the human study, will be performed over a span of 3 weeks and the aim is that 60 persons take part. The participants should be healthy, and have no diagnosed gut or stomach problems, and be 18 years old or older. They will be divided into groups, where one will be given living kombucha, one group kombucha sterilized by boiling (placebo) and the final group plain water (control group). The participants will drink one bottle (33 cl) of their designated beverage daily for two weeks. Fecal and saliva samples will be collected before, directly after and 10 days after the intervention. The samples will then be studied by sequencing the present organisms, after having extracted them. The library preparation will be made using Illumina sequencing. If possible, the aim is also to re-isolate a species from the kombucha after the study.

The participants will be registered for the study as they sign a consent form. These forms will then be treated as confidential material, and therefore be kept locked away at the institution. Only participating researchers will have access to the forms.

The participants will store the samples collected during the study until they are handed in for analysis. The samples will be destroyed during analysis.

The sample size has been chosen to a maximum of 60 participants, due to economical boundaries, but mainly because similar studied have used even fewer participants. As this is a pilot study more is not necessary. The intervention time (three weeks) was determined by comparison to other studies, but also restricted by the time scope of the project.

Study Timeline

• Study Start: 2018-04-01
• Primary Completion: 2018-05-02
• Study Completion: 2018-05-04
• Status Verified: 2019-03
• Study First Submitted: 2019-03-11
• Study First Submitted QC: 2019-03-12
• Last Update Submitted: 2019-03-12
• Study First Posted: 2019-03-13
• Last Update Posted: 2019-03-13

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 42

Inclusion Criteria

• The participants should be above 18 years of age.
• The participants must live in proximity of Lund or Helsingborg to be able to leave samples collected.
• The participants should consider themselves healthy and have no gut or stomach problems.

Exclusion Criteria

• The participants should not be diagnosed with any gut or stomach diseases or problems.
• The participants cannot consume any food with living microorganisms two weeks before, during of ten days after the intervention.
• Participants cannot use anti-microbial oral products during the study.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Heat-sterilized kombucha	Consumption of heat-sterilized kombucha	-
Living kombucha	Consumption of kombucha	-

Primary Outcome Measures

Name	Time	Method
The primary outcome is a change in the composition of the gut of oral micro flora, measured by extraction and sequencing of genetic material in fecal and saliva samples.	Samples will be collected before, directly after and ten days after the end of the intervention.	A library will be created using Illumina sequencing that will enable comparing the microbiological composition before and after the intervention.

Secondary Outcome Measures

Name	Time	Method
The secondary outcome of the study is to be able to re-isolate a species from the kombucha in the collected samples after the intervention.	Samples will be collected before, directly after and ten days after the intervention. The kombucha culture is studied before the intervention.	The secondary outcome will be measured by comparing results from the sequencing of microbes in the collected human samples and from the kombucha drink itself.

Trial Locations

Locations (1)

Lund University; 🇸🇪 Lund, Skåne, Sweden