UMIN-ICDS Clinical Trial

Public title

A Three-Year Observational Study on the Relationship Between Tsuruoka Food Culture, Gut Health, and Overall Health

Acronym

Tsuruoka Well-Eating Lab

Scientific Title

Prospective Cohort Study on the Association Between Tsuruoka Food Culture and the Gut Microbiota

Scientific Title:Acronym

TRIAD Study

Region

Japan

Condition

Dietary habits, gut environment, and physical and psychological health status

Classification by specialty

Not applicable

Classification by malignancy

Others

Genomic information

NO

Narrative objectives1

The primary objective of this study is to longitudinally investigate, over a three-year period, the association between habitual dietary diversity and the diversity and composition of the gut microbiota among adults residing in the Shonai region, with a particular focus on the food culture of Tsuruoka City, Yamagata Prefecture, a UNESCO Creative City of Gastronomy. This regional food culture includes traditional local crops, fermented foods, and seasonal dietary practices.
In addition, this study will collect multilayered data on dietary habits, gut microbiota, fecal metabolites, bowel habits, body composition, health-related quality of life (QOL), lifestyle behaviors, physical activity, and sleep, and will exploratorily investigate the associations between regional food culture and lifestyle factors, the gut environment, and physical and psychological health indicators.

Basic objectives2

Others

Basic objectives -Others

To explore the associations between dietary habits, including dietary diversity, and the gut microbiota and various health indicators.

Trial characteristics_1

Exploratory

Trial characteristics_2

Developmental phase

Not applicable

Primary outcomes

Gut microbiota alpha-diversity, assessed using the Shannon index.
The Shannon index will be calculated using 16S rRNA metagenomic analysis of stool samples. Values at baseline and at each assessment point during the three-year follow-up period, as well as longitudinal changes, will be evaluated. Associations with the Weekly Dietary Variety Score (WDS), the primary dietary exposure indicator, and other dietary indicators will also be examined.

Key secondary outcomes

1. Gut microbiota alpha-diversity indices, including the Chao1 index
2. Gut microbiota beta-diversity and community structure assessed using Bray-Curtis distance and other measures
3. Dietary intake indicators, including the Weekly Dietary Variety Score (WDS), intake of traditional local crops, and intake of fermented foods
4. Stool form assessed using the Bristol Stool Scale (BSS), bowel movement frequency, and other bowel habit measures
5. Body composition indicators, including body weight, BMI, body fat percentage, skeletal muscle mass, and visceral fat level
6. Health-related QOL assessed using the WHOQOL-BREF
7. Fecal metabolite profiles, including short-chain fatty acids and bile acids
8. Domain-specific health indicators, including menstrual-related symptoms, menopausal symptoms, and work productivity
9. Biological age calculated using epigenetic analytical methods based on buccal mucosa samples
10. Quantitative and qualitative data obtained from lifestyle behavior questionnaires and interviews
11. Data on beverage consumption behavior and related measures obtained using IoT weight sensors
12. Physical activity and sleep data obtained from Fitbit devices
13. Type, frequency, and severity of adverse events occurring during the study period

Study type

Observational

Basic design

Randomization

Randomization unit

Blinding

Control

Stratification

Dynamic allocation

Institution consideration

Blocking

Concealment

No. of arms

Purpose of intervention

Type of intervention

Interventions/Control_1

Interventions/Control_2

Interventions/Control_3

Interventions/Control_4

Interventions/Control_5

Interventions/Control_6

Interventions/Control_7

Interventions/Control_8

Interventions/Control_9

Interventions/Control_10

Age-lower limit

18

years-old

<=

Age-upper limit

Not applicable

Gender

Male and Female

Key inclusion criteria

Participants must meet all of the following criteria:
1. Adults aged 18 years or older who reside in the Shonai region of Yamagata Prefecture at the time informed consent is obtained
2. Individuals who are registered as gut microbiota donors at the Tsuruoka Kenben Room, or who have previously been registered as donors or undergone screening as potential donor candidates
3. Individuals who are willing to participate in three years of continuous follow-up, including four site visits per year and provision of study data
4. Individuals who have received sufficient explanation of the study based on the informed consent document and who voluntarily provide written informed consent to participate

Key exclusion criteria

Individuals meeting any of the following criteria will be excluded:
1. Individuals with a history of or currently undergoing treatment for serious gastrointestinal diseases, including inflammatory bowel disease, colorectal cancer, or status after extensive gastrointestinal resection
2. Individuals whom the principal investigator determines would have difficulty complying with the study protocol, including completion of self-administered questionnaires, regular study visits, or sample collection, due to psychiatric disorders, cognitive impairment, serious comorbidities, or other conditions
3. Individuals whom the principal investigator or study investigators otherwise determine to be unsuitable for safe and appropriate participation in the study

Target sample size

100

Name of lead principal investigator

1st name	Toru
Middle name
Last name	Takebayashi

Organization

Keio University

Division name

School of Medicine, Department of Preventive Medicine and Public Health

Zip code

160-8582

Address

35, Shinanomachi, Shinjuku-ku

TEL

03-5363-3758

Email

mirai@iab.keio.ac.jp

Name of contact person

1st name	Shin
Middle name
Last name	Kurosawa

Organization

Metagen Therapeutics, Inc.

Division name

Business Management Division

Zip code

997-0052

Address

F15, 246-2 Mizukami, Kakuganji, Tsuruoka, Yamagata 997-0052, Japan

TEL

0235-33-9966

Homepage URL

Email

tgi@metagentx.com

Institute

Keio University

Institute

Department

Personal name

Organization

Shonai Regional Industry Promotion Center
Metagen Therapeutics, Inc.
Canon Marketing Japan Inc.
Dentsu Inc.

Organization

Division

Category of Funding Organization

Other

Nationality of Funding Organization

Co-sponsor

Name of secondary funder(s)

Organization

Keio University School of Medicine Ethics Committee

Address

35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan

Tel

03-3353-1211

Email

med-rinri-jimu@adst.keio.ac.jp

Secondary IDs

NO

Study ID_1

Org. issuing International ID_1

Study ID_2

Org. issuing International ID_2

IND to MHLW

Institutions

Date of disclosure of the study information

2026

Year

10

Month

01

Day

URL releasing protocol

Publication of results

Unpublished

URL related to results and publications

Number of participants that the trial has enrolled

Results

Results date posted

Results Delayed

Results Delay Reason

Date of the first journal publication of results

Baseline Characteristics

Participant flow

Adverse events

Outcome measures

Plan to share IPD

IPD sharing Plan description

Recruitment status

Preinitiation

Date of protocol fixation

2026

Year

05

Month

25

Day

Date of IRB

Anticipated trial start date

2026

Year

09

Month

30

Day

Last follow-up date

2030

Year

03

Month

31

Day

Date of closure to data entry

Date trial data considered complete

Date analysis concluded

Other related information

This is a single-group, prospective cohort study involving adults residing in the Shonai region of Yamagata Prefecture. Individuals who are registered as gut microbiota donors at the Tsuruoka Kenben Room, or who have previously been registered as donors or screened as potential donor candidates, will be enrolled if they meet the eligibility criteria and provide informed consent to participate. The recruitment and enrollment period is planned to extend from the date of institutional authorization through March 2029.
Each participant will be followed for 36 months after enrollment and will, in principle, undergo a total of 12 assessments at three-month intervals. Data will be collected longitudinally, including gut microbiota analysis using stool samples, food frequency questionnaires (FFQ), bowel movement and dietary logs, body composition measurements, health-related QOL, lifestyle and medication status, and lifestyle behavior questionnaires and interviews.
Fecal metabolomic analysis and assessment of biological age using buccal mucosa samples will also be conducted in selected participants. Physical activity and sleep data will be collected continuously using Fitbit devices during the study period. In selected participants who provide consent, IoT weight sensors will also be used to measure beverage consumption behavior and related daily-life behaviors.
These data will be integrated to exploratorily analyze the associations between dietary habits, including dietary diversity, the gut environment, and various health indicators.
This study is partly supported by a grant from the FY2025 "Food Industry Creation Project" under the "Tsuruoka Gastronomic Innovation Plan," administered by the Shonai Regional Industry Promotion Center.

Registered date

2026

Year

10

Month

01

Day

Last modified on

2026

Year

10

Month

01

Day

Link to view the page

Value
https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000072261