Effect of Probiotic Intervention on Travel-Related Health Conditions During Short-Term Overseas Travel

September 10, 2025 updated by: Min-Tze LIONG, Universiti Sains Malaysia
International travel disrupts gut health through dietary changes, microbial exposure, and stress, often causing gastrointestinal symptoms like traveler's diarrhea and sleep disturbances. These shifts may increase antibiotic resistance risks. Probiotics may help stabilize gut microbiota and improve well-being during travel. This randomized, double-blind, placebo-controlled trial investigated whether probiotic supplementation mitigates gut microbiota perturbations, gastrointestinal symptoms, and sleep issues in adults traveling abroad. The investigators also assessed changes in anxiety, well-being, gut immunity, microbial function, and antibiotic resistance genes.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

International travel exposes individuals to abrupt changes in diet, water sources, microbial exposures, sleep schedules, and psychological stress. These factors often perturb the gut microbiota and influence host health outcomes. Studies have reported significant fluctuations in gut microbiota among travelers, even in those without diarrheal symptoms, with marked shifts in microbiome composition during short-term travel. Such perturbations are frequently accompanied by gastrointestinal symptoms and reduced well-being, highlighting the need for strategies to maintain gut homeostasis during travel.

Traveler's diarrhea remains one of the most common travel-related illnesses, with incidence rates varying from 30-70% depending on destination and season. Gastrointestinal discomfort during travel extends beyond diarrhea to include abdominal pain, abnormal gut transit, loose stools, and other non-diarrheal symptoms. These issues can significantly impact travel comfort and enjoyment.

International travel has also been associated with increased risk of acquiring antimicrobial-resistant organisms and genes, posing concerns for both individual and public health. The gut environment facilitates the selection and exchange of antibiotic resistance determinants, with studies showing increased abundance and diversity of antimicrobial resistance genes following travel.

Sleep disturbances represent another significant challenge during travel, arising from time zone changes and adaptation to new environments. These disruptions can profoundly affect well-being given sleep's critical role in health. The relationship between sleep and gut microbiota through the microbiome-gut-brain axis suggests that sleep disturbances during travel may contribute to gastrointestinal vulnerability through neuroendocrine, immune, and metabolic pathways.

Probiotics, defined as live microorganisms that confer health benefits when administered in adequate amounts, represent a potential intervention strategy. Evidence suggests probiotics enhance colonization resistance against pathogens, modulate immune responses, strengthen epithelial barrier integrity, and generate beneficial metabolites. Beyond gastrointestinal benefits, probiotics may influence systemic inflammation, lipid metabolism, and mental health outcomes through the gut-brain axis. While some evidence supports their role in reducing gastrointestinal transit time and constipation symptoms, as well as modest protection against traveler's diarrhea, robust data specifically regarding travel-related probiotic interventions remains limited.

The investigators conducted a randomized, double-blind, placebo-controlled trial in healthy adults undertaking short-term international travel. The study aimed to determine whether daily probiotic supplementation attenuates travel-associated perturbations in gut microbiota composition and diversity, while assessing concurrent changes in gastrointestinal symptoms, sleep quality, anxiety, and subjective well-being using validated instruments. Functional outcomes included assessment of specific microbial species, secretory immunoglobulin A, vitamin-related indices, antibiotic resistance genes, and metabolic pathway analyses to provide mechanistic insights. The investigators hypothesized that probiotic supplementation would stabilize the gut microbiota, enrich beneficial taxa and functions, and improve both gastrointestinal comfort and psychological outcomes compared with placebo.

Study Type

Interventional

Enrollment (Estimated)

46

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • China
    • Beijing Municipality
      • Haidian, Beijing Municipality, China, 100080
        • Recruiting
        • Tsinghua University Science and Technology
        • Contact:
        • Contact:
  • Malaysia
    • Pulau Pinang
      • George Town, Pulau Pinang, Malaysia, 11800

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Generally healthy adults
  • Scheduled to undertake a short-term round trip (less than 7 days) to abroad
  • Able to complete study procedures
  • Willing to take intervention products

Exclusion Criteria:

  • Use of antibiotics, probiotics, hormones, immunosuppressants, biologics or JAK inhibitors within four weeks prior to study
  • Chronic or severe systemic diseases (including cardiovascular, hepatic, renal, malignant or psychiatric disorders)
  • Uncontrolled parasitic infections
  • Long-term use of corticosteroids, growth hormone, vitamin B12, lysine or inositol
  • Major surgery within one month
  • Allergy to probiotic components
  • Other conditions deemed inappropriate by investigators

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo
Daily 6-drops of non-GMO corn starch in medium-chain triglyceride oil
Other: Placebo
Daily 6-drops of non-GMO corn starch in medium-chain triglyceride oil
Experimental: Probiotic
Daily 6-drops of Bifidobacterium longum subsp. infantis M-63, B. breve M-16V, and B. longum BB536 in non-GMO corn starch as excipient, in medium-chain triglyceride oil (1.5 × 109 CFU/day)
Other: Probiotic
Daily 6-drops of Bifidobacterium longum subsp. infantis M-63, B. breve M-16V, and B. longum BB536 in non-GMO corn starch as excipient, in medium-chain triglyceride oil (1.5 × 109 CFU/day)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Microbiota profiles of fecal samples in generally healthy adults upon administration of probiotic as assessed via metagenomics sequencing
Time Frame: 7 days
Differences in microbiota abundance in fecal sample of generally healthy adults upon administration o probiotic compared to placebo
7 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Gastrointestinal metabolites in generally healthy adults upon administration of probiotic as assessed using LC-MS
Time Frame: 7 days
Differences in concentrations of gastrointestinal metabolites upon administration of probiotic compared to placebo
7 days
Respiratory symptoms duration and frequency in generally healthy adults upon administration of probiotic as assessed using questionnaire
Time Frame: 7 days
Changes in duration and frequency of respiratory illnesses symptoms from generally healthy adults on probiotic or placebo after 7-days, via the use of standard clinical assessment questionnaire, scale 0-3 where higher scores indicate more severe symptoms.
7 days
Gastrointestinal symptoms in generally healthy adults upon administration of probiotic as assessed using questionnaire
Time Frame: 7 days
Differences in duration and frequency of gastrointestinal symptoms upon administration of probiotic compared to placebo via the use of standard clinical assessment questionnaire, scale 0-3 where higher scores indicate more severe symptoms.
7 days
Allergy symptoms in generally healthy adults upon administration of probiotic as assessed using questionnaire
Time Frame: 7 days
Differences in duration and frequency of allergy symptoms upon administration of probiotic compared to placebo via the use of standard clinical assessment questionnaire, scale 0-3 where higher scores indicate more severe symptoms.
7 days
Quality of life in generally healthy adults upon administration of probiotic as assessed using questionnaire
Time Frame: 7 days
Differences in quality of life via the use of questionnaires such as anxiety (GAD-7, scale 0-3 where higher scores indicate more severe outcomes), sleep (PSQI, scale 0-3 where higher scores indicate more severe outcomes) and well-being (WHO-5, scale 0-5 where higher scores indicate better outcomes) upon administration of probiotic compared to placebo.
7 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Universiti Sains Malaysia

Collaborators

Tsinghua University Science and Technology

Investigators

  • Principal Investigator: Ai Zhou, Ph.D., Tsinghua University Science and Technology

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 31, 2025

Primary Completion (Estimated)

December 31, 2025

Study Completion (Estimated)

December 31, 2025

Study Registration Dates

First Submitted

September 1, 2025

First Submitted That Met QC Criteria

September 1, 2025

First Posted (Estimated)

September 9, 2025

Study Record Updates

Last Update Posted (Estimated)

September 17, 2025

Last Update Submitted That Met QC Criteria

September 10, 2025

Last Verified

September 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • THU-01-2025-1007

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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