The Effects of a Postbiotic Supplement on Biomarkers of Gut Health

The Effects of a Postbiotic Supplement on Biomarkers of Gastrointestinal, Cardiometabolic and Immunometabolic Health

This study is a randomized, double-blind, two-arm, placebo-controlled trial of N=80 (40/arm) apparently healthy men and women between 18 and 65 years old to be recruited at a single investigational center in Northeast Ohio (i.e., The Center for Applied Health Sciences).

This study will assess the effectiveness of a postbiotic supplement on various biomarkers of health. Consumption of this dietary supplement is not intended to diagnose, treat, cure, or prevent any disease.

Participants will attend three in-person study visits. During Visit 1, participants will be screened for participation (i.e., medical history, routine blood work, background baseline diet). Over the next 4 weeks, participants will attend two in-person visits: [visit 2 (week 0) and visit 3 (week 4)] wherein assessments of gut function [fecal microbiome diversity, short chain fatty acids (SCFA), and fecal butyrate], serum butyrate, serum zonulin, salivary cortisol, and Gastrointestinal Symptom Rating Scale (GSRS) for gastrointestinal (GI) health, emotional states [Depression, Anxiety and Stress Scale (DASS21)], and quality of life (SF-36 questionnaire) will be assessed. Participants will also be provided home kits with instructions on how to collect stool and saliva samples on two separate occasions (i.e., visit 2, visit 3) during the study.

• Comprehensive side effect profile/ adverse event monitoring will take place throughout the study duration. The study will be conducted following ICH-GCP guidelines to ensure participant safety and scientific integrity of the data.

Study Overview

• Status: Completed
• Conditions: Microbiota; Gastrointestinal; Cortisol; Bloating; Butyrate; Immuno-modulation; Microbiota Balance; Gastrointestinal Upset
• Intervention / Treatment: Dietary supplement: Postbiotic

• Study Type: Observational
• Enrollment (Actual): 76

Contacts and Locations

Study Locations

• United States
  • Ohio
    • Canfield, Ohio, United States, 44406
      • The Center for Applied Health Sciences

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Probability Sample

Study Population

Apparently healthy men and women between 18 and 65 years old, located in Northeast Ohio.

Description

Inclusion Criteria:

• Provide voluntary signed and dated informed consent. • Be in good health as determined by medical history and routine blood chemistries.

Age between 18 and 65 years (inclusive).

• Body Mass Index of 18.5-34.9 (inclusive).

• Body weight of at least 110 pounds.

• Normotensive (seated, resting systolic blood pressure <140 mm Hg and diastolic blood pressure < 90 mm Hg. If the first measurement is slightly elevated above these limits, the participant will be given a brief (5-minute) rest period, and two more measurements will be taken. The average of all three measurements will be used to determine eligibility.

• Normal seated, resting heart rate (<90 per minute).

• Willing to duplicate their previous 24-hour diet, refrain from caffeine for 24 hours, abstain from exercise for 48 hours prior, and fast for 10 hours prior to each laboratory visit.

• Participant agrees to maintain existing dietary and physical activity patterns throughout the study period.

• Participant is willing and able to comply with the study protocol.

• No medical history of gastrointestinal distress.

• Avoidance of cultured and fermented foods such as yogurt, kefir, kombucha during the duration of the study.

Exclusion Criteria:

• Current use of prebiotics, probiotics, postbiotics, or antibiotics within the past 4 weeks or use of any dietary supplement that may confound the study or its endpoints.

Current use of GLP-1 inhibitors. • Individuals that adhere to a vegan diet.

• History of unstable or new-onset cardiovascular/cardiorespiratory, liver, or renal disease.

Current or previous diagnosis of prediabetes, diabetes, or an endocrine disorder.

• Fasting blood glucose of > 125 mg/dL.

• Alcohol consumption (more than 2 standard alcoholic drinks per day or more than 10 drinks per week) or drug abuse or dependence within the past 6 months.

• Current smokers or smoking within the past month.

• Current use of aspirin, or pharmaceuticals impacting mucin such as, but not limited to Mucinex (guaifenesin).

• History of hyperparathyroidism or an untreated thyroid disease.

• History of malignancy in the previous 5 years except for non-melanoma skin cancer (basal cell cancer or squamous cell cancer of the skin).

• Prior gastrointestinal bypass surgery (Lapband), etc.

• Being treated for or having other known gastrointestinal or metabolic diseases that might impact nutrient absorption or metabolism, e.g., short bowel syndrome, IBS/IBD, diarrheal illnesses, history of colon resection, gastro paresis, Inborn-Errors-of-Metabolism (such as PKU).

• Chronic inflammatory condition or disease (e.g., rheumatoid arthritis, Crohn's disease, ulcerative colitis, IBS/IBD, Lupus, HIV/AIDS, etc.).

• Previous medical diagnosis of gout or fibromyalgia.

• Individuals who are cognitively impaired and/or who are unable to give informed consent.

• Pregnant, trying to become pregnant, less than 120 days postpartum, or are nursing. Women who participate in this study must agree to the use of contraception for the duration of the study and any woman that is sexually active will have to take a negative pregnancy test prior to enrolling. Women of childbearing age (any woman prior to menopause) regardless of their use of contraception will be provided a urine pregnancy test kit at their screening visit and take the test in private using the female lavatory after signing an informed consent.

• Clinically significant abnormal laboratory results at screening.

• Known sensitivity to any ingredient in the test formulations as listed in the study product.

• Currently participating in another research study with an investigational product or have been in another research study in the past 30 days.

• Any other diseases or conditions that, in the opinion of the medical staff, could confound the primary endpoints or place the participant at increased risk of harm if they were to participate.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Placebo Group; Participants who meet the study eligibility criteria will be randomly assigned to the study product or the placebo group. The study placebo will only contain maltodextrin.
Postbiotic Study Product; Participants who meet the study eligibility criteria will be randomly assigned to the study product or the placebo group. The study product will contain Keystone postbiotic and maltodextrin.	Dietary supplement: Postbiotic; 300mg

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evaluate the change in fecal microbiome diversity.	The primary outcome is to observe a change in the fecal microbial populations in between the postbiotic group and the placebo control group from intake and baseline to the end of the study period. This will be measured by a change in fecal microbial populations by DNA analysis at the genus, species and strain level (where possible) between the placebo and study group. Baseline period will be compared as well. Both alpha and beta diversity will be assessed as well.	Participants will complete up to 5-week study consisting from screening, randomization, and enrollment periods to the end of treatment at 4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evaluate the impact of a Postbiotic on short chain fatty acid production	A secondary outcome is to evaluate the impact of keystone postbiotic on short chain fatty acid production. This will be measured by a change in the SCFA profile in fecal samples as assessed by GC/MS, between placebo control group and the postbiotic group. Blood samples will also be taken to evaluate circulating butyrate levels between placebo control group and the postbiotic group. GCMS detection is determined by peak area values. Higher values at the end of the trial suggest more SCFA are being produced.	Participants will complete the trial from enrollment to the end of the 4-week treatment.
Evaluate the impact of keystone postbiotic on serum zonulin	A secondary outcome is to evaluate the impact of keystone postbiotic on serum zonulin. This will be measured by a change in numerical value of zonulin (ng/ml) between the placebo and study group as well as a change from baseline to the end of the study at 4-weeks. Higher values of serum zonulin suggest increased permeability of the intestinal epithelium.	Participants will complete the trial from enrollment to the end of the 4-week treatment.
Evaluate the impact of keystone postbiotic on salivary cortisol.	A secondary outcome is to evaluate the impact of the postbiotic on salivary cortisol as a measure of stress. This will be measured by a change in salivary cortisol (ug/dL) between placebo and study product group. Baseline period will be assessed as well. Higher levels of salivary cortisol suggest more stress (physical, immune related or psychological) which is a worse outcome.	Participants will complete the trial from enrollment to the end of the 4-week treatment.
Evaluate the impact of keystone postbiotic on Quality of Life	A secondary outcome will be measured by a change in the SF-36 (36-Item Short Form Survey) score between placebo and study product group to assess quality of life. Baseline period will be compared as well. On a scale between 0-100, a higher SF-36 score indicates better health.	Participants will complete the trial from enrollment to the end of the 4-week treatment.
Evaluate the impact of keystone postbiotic on emotional state.	A secondary outcome is to evaluate the impact of the postbiotic on emotional health. This will be assessed by a change in the DASS-21 (depression, anxiety and stress -21 items) assessment. On a scale between 0-42, a higher DASS-21 score indicates more severe emotional distress, which is a worse outcome.	Participants will complete the trial from enrollment to the end of the 4-week treatment.
Evaluate the impact of keystone postbiotic on gastointestinal health	A secondary outcome is to evaluate the impact of the postbiotic on gastrointestinal health. This will be measured by a change in the GSRS (gastrointestinal symptoms rating scale) score between placebo and study product groups. Baseline period will be compared as well. On a scale of 15-105, a higher GSRS score indicates more severe symptoms, which is a worse outcome.	Participants will complete the trial from enrollment to the end of the 4-week treatment.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evaluate the safety and tolerability of keystone postbiotic through measurement of vital signs and adverse event recording.	A prespecified outcome is to assess the safety and tolerability of the postbiotic as determined by measurements of vital signs (heart rate and blood pressure) and tracking of adverse events in the placebo and study product group. Baseline period will be compared as well. Elevation of heart rate, blood pressure or an increased rate of adverse events indicate worse outcomes.	Participants will complete the trial from enrollment to the end of the 4-week treatment.

Collaborators and Investigators

• Sponsor: Verb Biotics LLC
• Investigators: Principal Investigator: Tim Ziegenfuss, Ph.D., FISSN, CSCS, Center for Applied Health Sciences

Study record dates

Study Major Dates

• Study Start (Actual): November 5, 2024
• Primary Completion (Actual): April 26, 2025
• Study Completion (Actual): April 26, 2025

Study Registration Dates

• First Submitted: March 25, 2026
• First Submitted That Met QC Criteria: April 6, 2026
• First Posted (Actual): April 14, 2026

Study Record Updates

• Last Update Posted (Actual): April 14, 2026
• Last Update Submitted That Met QC Criteria: April 6, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: VERB-0924-005

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