Kimchi and Gut Health

Kimchi and Gut Health - Kimchi Effects on the Human Gut Microbiome

The goal of this study is to learn about the effects of eating kimchi on the gut health of healthy adults in the USA. The investigators will be researching the changes in the gut microbiome, biomarkers of gut health and cardiometabolic health after consuming fermented and unfermented cabbage.

The main questions it aims to answer are:

Does eating kimchi (fermented cabbage) result in enrichment of lactic acid bacteria in the stools of participants? Does eating kimchi result in metabolic changes in the gut microbiome, biomarkers of gut and cardiometabolic health of participants? Researchers will compare a group of participants eating fermented cabbage (kimchi) daily to a group of participants eating non-fermented cabbage daily.

Participants will:

Eat kimchi or cabbage daily for 3 weeks. Visit the study site for brief visits up to 5 times. Have blood drawn and provide a fecal sample 2 times - at beginning and end of the 3 week study.

Keep occasional records of food intake and questionnaires about any gastrointestinal symptoms that participants may have.

Study Overview

• Status: Recruiting
• Conditions: Healthy Adult Participants
• Intervention / Treatment: Other: 60 grams per day of intervention food; Other: 60 grams per day of intervention food

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Davis, California, United States, 95616
      • Recruiting
      • Ragle Human Nutrition Center
      • Contact: Francene Steinberg, PhD; Phone Number: 530-752-0120; Email: fmsteinberg@ucdavis.edu
    • Davis, California, United States, 95616
      • Recruiting
      • UC Davis Ragle Human Nutrition Research Center
      • Contact: Francene Steinberg, PhD; Phone Number: 530-752-0160; Email: fmsteinberg@ucdavis.edu
      • Contact: Jody Randolph; Phone Number: 5307527620; Email: jmrandolph@ucdavis.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• BMI of 25-30 kg/m2
• No or occasional consumption of kimchi (3 or fewer times per week)
• Willing to eat study food every day for 3 weeks
• Willing to participate in study protocols

Exclusion Criteria:

• Allergy to cabbage and /or cruciferous family vegetables
• Allergy to kimchi ingredients such as shellfish and fish sauce
• Daily consumption of kimchi
• Diagnosed digestive issues such as irritable bowel syndrome (IBS) or gastrointestinal inflammatory bowel disease (IBD) or conditions such as Crohn's disease
• Previous bowel surgery that disrupts the digestive flow, motility or gastric emptying process
• Antibiotics used in the 2 months prior to enrollment
• Unwillingness to discontinue probiotics during study and washout period
• Active diagnosis and/or treatment for cancer

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Kimchi	Other: 60 grams per day of intervention food; Non-fermented cabbage; Other: 60 grams per day of intervention food; Kimchi fermented cabbage
Active Comparator: Cabbage	Other: 60 grams per day of intervention food; Non-fermented cabbage; Other: 60 grams per day of intervention food; Kimchi fermented cabbage

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change from baseline in fecal Lactic Acid Bacteria (LAB)	Baseline and week 3

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fecal Metabolites - Change in short chain fatty acids (SCFA) and secondary bile acids (BA)		Baseline and 3 weeks
Gut integrity and health - Change in fecal calprotectin, fecal lipocalin, and fecal sIGA		Baseline and 3 weeks
Gut integrity and health - Change in plasma lipopolysaccharide binding protein (LBP), lipopolysaccharide (LPS), zonulin, and sCD14		Baseline and 3 weeks
Immune biomarkers - Change in plasma IL-6, TNF-alpha, hsCRP		Baseline and 3 weeks
Cardiometabolic biomarkers - Change in lipid panel (TC, LDL, HDL, TG), and oxidized LDL (oxLDL)		Baseline and 3 weeks
Qualitative self-assessment of gut associated health - Change in Gastrointestinal Symptom Rating Scale (GSRS)	This questionnaire rates gastrointestinal symptoms over the past 7 days. A higher score indicates presence and increasing severity of symptoms and level of discomfort.	Baseline and 3 weeks
Qualitative self-assessment of gut associated health - Change in Digestion-associated Quality of Life Questionnaire (DQLQ)	This questionnaire measures the effect of digestive symptoms on daily life over the past 7 days. A higher score indicates a lower (worse) digestion-associated Quality of Life.	Baseline and 3 weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body Mass Index (BMI)	To derive the Body Mass Index (BMI) the following will be done: Height will be measured in meters. Weight will be measured in kilograms. These values will be aggregated to arrive at one reported value to report BMI in kg/m2	Baseline and 3 weeks
Dietary Records and nutritional analysis of Macronutrients	ASA24 (Automated Self Assessment of diet on the NIH website) will be used to record 24 hours of diet intake. Macronutrients will be measured in grams/day.	Baseline, week 1 of intervention, week 3 of intervention
Dietary records and assessment of Fiber intake	ASA24 (Automated Self Assessment of diet on the NIH website) will be used to record 24 hours of diet intake. Dietary fiber will be measured in grams/day.	Baseline, weeks 1 and 3
Waist Circumference	Waist circumference will be measured in centimeters	Baseline and 3 weeks
Blood Pressure	Blood pressure will be measured by automated upper arm cuff to read systolic and diastolic pressure in units of mm Hg. Normal pressure is considered 120/80 mm Hg.	Baseline and 3 weeks

Collaborators and Investigators

• Sponsor: University of California, Davis

Study record dates

Study Major Dates

• Study Start (Actual): March 30, 2026
• Primary Completion (Estimated): January 30, 2027
• Study Completion (Estimated): December 1, 2029

Study Registration Dates

• First Submitted: December 22, 2025
• First Submitted That Met QC Criteria: February 20, 2026
• First Posted (Actual): February 27, 2026

Study Record Updates

• Last Update Posted (Actual): April 2, 2026
• Last Update Submitted That Met QC Criteria: April 1, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Fermented food; Healthy adult; GI health
• Other Study ID Numbers: 2325615-1

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No