Clinical trial NCT03873350: The Effect of the Fermented Tea Beverage Kombucha on the Oral and Gut Microflora
Official title: The Effect of the Fermented Tea Beverage Kombucha on the Human Microflora: a Placebo-controlled Study
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Microbial Colonization
Keywords: Microbiota colonization kombucha bacteria yeast
Lead sponsor: Lund University
Sponsor class: OTHER
First posted: 2019-03-13
Enrollment: 42
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: The participants will be divided into three groups in which one is given living kombucha, one heat-sterilized kombucha (placebo group) and one regular tap water (control group).
Primary purpose: OTHER

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.

Eligibility criteria: 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.

Primary outcomes:
measure: 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.
timeFrame: Samples will be collected before, directly after and ten days after the end of the intervention.
Secondary outcomes:
measure: 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.
timeFrame: Samples will be collected before, directly after and ten days after the intervention. The kombucha culture is studied before the intervention.
Other outcomes:
Locations:
city: Lund
country: Sweden
facility: Lund University
state: Skåne
Study officials:
References: