The Effects of Probiotic Supplementation on State and Trait Stress, Anxiety, and Depression Symptoms in Stressed Adults

NCT ID: NCT07216729

Last Updated: 2025-11-18

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 150 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-02-20
• Study Completion Date: 2024-06-01

Brief Summary

The goal of this randomized controlled trial is to learn if supplementation with the probiotic Lactobacillus reuteri DSM 17938 can reduce levels of trait and state perceived stress, anxiety, and depressive symptoms compared to a placebo in a population of stressed adults ages 18-45. This study also investigates several evidence-based moderators of treatment effects, evaluates whether the probiotic caused side effects, and evaluates whether effects endured at 1-month post-supplementation.

Conditions

Anxiety Symptoms; Perceived Stress; Depressive Symptoms

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: SUPPORTIVE_CARE
• Blinding Strategy: DOUBLE

Study Groups

Probiotic

5 drops daily (100 million colony-forming units) for 46 days of Lactobacillus reuteri DSM 17938 in sunflower oil, medium chain triglyceride oil, and silicon dioxide.

Group Type: EXPERIMENTAL

Lactobacillus reuteri DSM 17938

Intervention Type: DIETARY_SUPPLEMENT

5 drops (100 million CFUs) daily for 46 days of L. reuteri DSM 17938 in sunflower oil, medium chain triglyceride oil, and silicon dioxide.

Placebo

5 drops daily for 46 days of a placebo consisting of the inactive ingredients from the probiotic supplement, specifically sunflower oil, medium chain triglyceride oil, and silicon dioxide.

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: OTHER

5 drops daily for 46 days of placebo consisting of inactive ingredients from probiotic supplement, specifically sunflower oil, medium chain triglyceride oil, and silicon dioxide.

Interventions

Lactobacillus reuteri DSM 17938

5 drops (100 million CFUs) daily for 46 days of L. reuteri DSM 17938 in sunflower oil, medium chain triglyceride oil, and silicon dioxide.

Intervention Type: DIETARY_SUPPLEMENT

Placebo

5 drops daily for 46 days of placebo consisting of inactive ingredients from probiotic supplement, specifically sunflower oil, medium chain triglyceride oil, and silicon dioxide.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• age 18 - 45
• scoring 14+ on the perceived stress scale-10 indicating medium stress or higher
• ability to provide informed consent
• willingness not to take probiotic supplements (pills, tablets, oils, etc.) other than the product provided in the clinical study until all study procedures are completed
• own a smartphone and are willing to receive study materials and complete study procedures by text

Exclusion Criteria

• a history of gastrointestinal discomfort or surgery, urinary incontinence, cancer, toxic shock syndrome, frequent diarrhea, vital signs outside of the acceptable range (i.e., blood pressure >160/100, oral temperature >100°F, pulse >100), heart disease, heart attack, lung/respiratory disease, any pulmonary, cardiovascular, gastrointestinal, hepatic or renal functional abnormality (i.e. a medical diagnosis related to lungs, heart, stomach/intestines, liver, or kidneys), HIV, Hepatitis B, Hepatitis C, bipolar disorder, psychosis, or confirmed or suspected immunosuppression or immunodeficiency
• current (past month) alcohol or substance abuse or dependence (score of 2+ on the UNCOPE)
• consistent (e.g., 5x/week or greater) probiotic supplementation within the last month, including probiotic food products such as yogurt
• receiving antibiotics within the last month
• receiving medications that interfere with gut motility (opiates, loperamide, stool softeners)
• use of systemic antibiotics, antifungals, antivirals, or antiparasitics (intravenous, intramuscular, or oral)
• use of oral, intravenous, intramuscular, nasal or inhaled corticosteroids
• use of cytokines or cytokine inhibitors
• use of methotrexate or immunosuppressive cytotoxic agents
• receiving immunosuppressive drugs/medications or treatment including antineoplastic therapy, post-transplantation immunosuppressive therapy, and/or radiation therapy
• participation in conflicting interventional research protocol
• unstable dietary history as defined by major changes in diet during the previous month, where the subject has eliminated or significantly increased a major food group in their diet
• female who is pregnant or lactating or reports expecting to get pregnant during the course of the study
• currently involved in the criminal justice system as a prisoner or ward of the state

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University of Colorado, Boulder

OTHER

Sponsor Role: lead

Responsible Party

Lauren Finkelstein

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Lauren B Finkelstein, MA

Role: PRINCIPAL_INVESTIGATOR

University of Colorado, Boulder

Locations

University of Colorado Boulder, Muenzinger Psychology Building

Boulder, Colorado, United States

Countries

United States

Related Links

https://osf.io/a6htn

Prior pre-registration on Open Science Framework, initially submitted prior to starting data collection

Other Identifiers

22-0234

Identifier Type: -

Identifier Source: org_study_id