Fermented Vegetables and Gut Microbiome Pilot Study

Launched by USDA, WESTERN HUMAN NUTRITION RESEARCH CENTER · Mar 13, 2025

Keywords

ClinConnect Summary

This clinical trial is looking at how eating fermented vegetables may affect gut health in healthy adults. Specifically, the researchers want to see if these foods can increase certain beneficial bacteria in the gut and how well people can tolerate them. The study is currently recruiting participants aged 18 to 65 who are not obese, meaning their body mass index (BMI) is between 18.5 and 39.9. However, individuals with certain health conditions, who are pregnant or breastfeeding, or who have recently taken specific medications or supplements may not qualify.

If you decide to participate, you'll be asked to consume fermented vegetables for a period of time and share some stool samples to help the researchers understand how your gut responds. It's important to note that participants will need to avoid other fermented foods and probiotics during the trial. This study is a preliminary step before testing the effects of fermented vegetables in older adults, so it’s a great opportunity to contribute to research that could improve gut health for everyone!

Gender

ALL

Eligibility criteria

• • We will enroll non-obese adults aged 18-65 years, with BMI between 18.5 and 39.9 kg/m2. We will exclude people with a high blood pressure, who cannot consume fermented vegetables, and those among whom a medical condition, use of medication, use of probiotic supplements or consumption of fermented foods may influence trial outcomes. Those who are uncomfortable with the stool sample collection protocol, or who may not be able to complete the stool samples due to infrequent bowel movements, will also be excluded.
• • Adults who are unable to consent, individuals who are not yet adults (infants, children, teenagers), pregnant women, and prisoners will be excluded from participation in the study.
• Inclusion Criteria:
• • Age 18 - 65 years
• • BMI 18.5 - 39.9 kg/m2
• Exclusion Criteria:
• • BMI less than 18.5 or greater than 39.9
• • Pregnant or breastfeeding
• • Allergy or sensitivity to any fruit or vegetable
• • Dietary restriction preventing consumption of fermented vegetables
• • Consumption of probiotic supplements, foods or drinks in the past month
• • Probiotic supplements include any tablets, liquids, powders, chewables or other formulations that provide high-quantity, live probiotic microbes
• • Probiotic foods and drinks include products labeled as 'probiotic' because they contain live microbes in types and quantities that may confer a health benefit
• • Regular consumption, defined as consumption more than once per week in the past two weeks, of live microbe-containing fermented vegetables or cultured dairy products, such as kimchi, refrigerated fermented pickles, traditional (lacto-fermented) sauerkraut, yogurt, or kefir
• • In case of less frequent consumption, defer study start such that baseline assessments are completed at least two weeks after last intake
• • Unwillingness to abstain from non-study fermented foods and probiotics during the trial
• • Uncomfortable with or unwilling to complete stool sample or saliva collections
• • Current participation in another interventional research study
• • Having fewer than 3 bowel movements per week
• • Unmanaged hypertension, defined as blood pressure greater than or equal to 140/90 mmHg
• * Current diagnosis of:
• • Disease that affects the immune system or causes immune impairment, including HIV/AIDS
• • Cancer
• • Diabetes
• • Asthma with daily medication
• • Primary immune deficiency
• • Auto-immune disease
• • Chronic gastrointestinal disorder (e.g. Crohn's disease, irritable bowel syndrome, colitis, gastric ulcer)
• • Chronic kidney disease
• * Current use for 2 weeks or longer of:
• • Any drug that affects the immune system, such as immunosuppressants, immune modifying drugs, or corticosteroids (e.g. cortisone, prednisone, methylprednisolone)
• • Biologics (e.g. Lantus, Remicade, Rituxan, Humira, Herceptin, Avastin, Lucentis, Enbrel)
• • GLP-1 agonists, such as semaglutide and tirzepatide.
• • Antidiabetic medications, such as Metformin.
• • Diuretics, such as Hydrochlorothiazide
• • Use of sulfonamides or antimicrobials, including antibiotics, antifungals, antivirals, and antiparasitic medications in the past 3 months
• • Use of laxatives in the past 2 weeks
• • Currently undergoing cancer treatment with radiation or drugs
• • History of gastrointestinal surgery that would impact study outcomes, such as gastric bypass, intestinal resection, surgeries of the liver or pancreas, or removal of part or all of any organ of the GI tract
• * Having within the past 2 weeks:
• • Diarrheal illness, defined as passing 3 or more abnormally loose or watery stools in a 24-hour period
• • Persistent vomiting
• • Fever
• * Having within the past 3 months:
• • Surgery
• • Hospitalization
• * Having within the past 1 month:
• • Colonoscopy