Kimchi Powder on Gut Health

Inclusion Criteria: * Adults, male or female, aged 20 to 70 years * Body mass index of 25 kg/m2 or more and less than 30 kg/m2 * Meeting the Rome IV criteria for diarrhea-predominant irritable bowel syndrome (IBS-D), defined as Bristol Stool Form Scale type 6 or 7 in 25% or more of bowel movements from 2 weeks before screening through the day of the screening visit * No inflammatory bowel disease or malignancy * Provided written agreement to refrain from consuming kimchi-containing foods for the duration of the study (approximately 2 months) Exclusion Criteria: * Drug-induced constipation * Constipation secondary to another condition, such as diabetes mellitus or thyroid disease * History of intra-abdominal surgery other than appendectomy (including gastrectomy, gastric bypass, gallbladder or biliary tract surgery, pancreatectomy, bowel resection with particular reference to the ileum, and colorectal surgery or insertion procedures) * Uncontrolled hypertension (resting blood pressure 160/100 mmHg or higher) * Uncontrolled diabetes mellitus (fasting blood glucose 160 mg/dL or higher) * Uncontrolled hypothyroidism or hyperthyroidism * AST or ALT concentration 3 times or more the upper limit of the reference range of the testing laboratory * Creatinine concentration 2 times or more the upper limit of the reference range of the testing laboratory * Severe cardiovascular or cerebrovascular disease or malignancy within the previous 6 months * Psychiatric disorder such as severe affective disorder, schizophrenia, or substance use disorder, or current use of related psychiatric medication (intermittent use for sleep disturbance is permitted) * Severe alcohol use disorder * Heavy smoking (20 cigarettes per day or more) * Hypersensitivity to the main ingredient or components of the study food * Severe gastrointestinal symptoms such as heartburn or dyspepsia * Use of medications or foods that may affect the study results, including kimchi and probiotics * For female volunteers, suspected pregnancy, lactation, or plan to become pregnant during the study period * Participation in another drug clinical trial within one month prior to the screening date, or planned participation * Judged unsuitable for participation by the principal investigator for reasons other than those listed above