Gut Microbiome Response to Long-Haul Travel in Elite Football Players

NCT07585474 | Enrolling By Invitation

• 1 other identifier: ER79032366
• Study Type: interventional
• Target: 30
• Locations: 2 countries
• Sites: 2

Brief Summary

The goal of this randomised control trial is to measure the gut microbiome response to long-haul travel alongside the demands of pre-season amongst elite football players. The efficacy of a probiotic in modulating the gut microbiome to mitigate the detrimental impacts of long-haul travel as well as training in the heat will also be explored. The main questions this study aims to answer are:

• How is the gut microbiome of the professional football player impacted by long-haul travel during the pre-season period?
• How is immune function impacted by the demands of pre-season?
• Can a probiotic dietary maintain gut microbial stability in response to long-haul travel? Researchers will compare the effects of the probiotic supplement with a placebo. Participants will be required to:
• Provide a faecal sample at multiple points throughout the pre-season
• Provide a saliva sample at multiple points throughout the season
• Consume a daily supplement which will either be a placebo or probiotic capsule

Conditions

Microbial Composition; Immune Function

Keywords

Gut microbiome; Probiotics; Pre-Season; Football; Long-Haul; Travel

Outcome Measures

Primary Outcomes (1)

• Gut Microbiome

  The gut microbiome is the complex community of microorganisms in the gastrointestinal tract that plays a vital role in digestion, immune regulation, and overall physiological resilience. In elite athletes, long-haul travel and pre-season training in hot environments can place additional stress on the gastrointestinal system, potentially leading to dysbiosis, gastrointestinal discomfort, and impaired performance or recovery.

  3-4 weeks

Secondary Outcomes (1)

• Salivary IgA

  3-4 weeks

Study Arms (2)

Active Treatment Group

EXPERIMENTAL

All participants receive probiotic once orally for 3-4 weeks

Drug: Probiotic Capsule

Placebo

PLACEBO COMPARATOR

Participants receive matching placebo orally once daily for 3-4 weeks

Drug: Placebo

Interventions

Probiotic Capsule DRUG

Probiotic capsule administered orally once daily for 3 weeks

Active Treatment Group

Placebo DRUG

Placebo tablet, identical in appearance to probiotic, administered orally once daily for 3-4 weeks.

Placebo

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Male professional footballers who are involved in regular training during the pre-season period.
• Generally healthy, with no acute or chronic illnesses that could interfere with the study intervention or outcomes.
• Not currently consuming probiotics, prebiotics, or antibiotics within 4 weeks prior to enrolment.
• Willing to refrain from starting any new dietary supplements or probiotics during the study period.
• Able and willing to provide written informed consent.

You may not qualify if:

• History of gastrointestinal disorders (e.g., Crohn's disease, ulcerative colitis, irritable bowel syndrome) or chronic diseases that could interfere with probiotic metabolism or study outcomes.
• Acute illness (e.g., infection) within 2 weeks prior to enrollment.
• Known allergy or hypersensitivity to components of the probiotic or placebo. - - - Use of antibiotics, probiotics, prebiotics, or synbiotics within 4 weeks prior to study start.
• Use of immunosuppressive medications or other supplements likely to impact gut microbiota.
• Regular use of alcohol or drugs at levels that could interfere with study participation or outcomes.
• Participation in another clinical trial within the past 3 months.
• Any injury or medical condition that limits participation in full training or matches during the study period.

Sponsors & Collaborators

• Sheffield Hallam University: lead
• University of Leeds: collaborator

Study Sites (2)

1 Hotel Nashville

Nashville, Tennessee, 37203, United States

Location

Bodymoor Heath

Tamworth, West Midlands, B78 2BB, United Kingdom

Location

Related Publications (1)

• References Bielik, V., Hric, I., Ugrayová, S., Kubáňová, L., Putala, M., Grznár, Ľ., Penesová, A., Havranová, A., Šardzíková, S. and Grendar, M. (2022) Effect of high-intensity training and probiotics on gut microbiota diversity in competitive swimmers: randomized controlled trial. Sports medicine-open, 8(1), p. 64. Borg, G. A. (1982) Psychophysical bases of perceived exertion. Medicine and science in sports and exercise, 14(5), pp. 377-381. Cani, P. D., Van Hul, M., Lefort, C., Depommier, C., Rastelli, M. and Everard, A. (2019) Microbial regulation of organismal energy homeostasis. Nature metabolism, 1(1), pp. 34-46. Casa, D. J., Becker, S. M., Ganio, M. S., Brown, C. M., Yeargin, S. W., Roti, M. W., Siegler, J., Blowers, J. A., Glaviano, N. R. and Huggins, R. A. (2007) Validity of devices that assess body temperature during outdoor exercise in the heat. Journal of athletic training, 42(3), p. 333. Chantler, S., Wood-Martin, R., Holliday, A., Davison, G., Crabtree, D. R., Readhead, C. and Jones, B. (2024) The frequency and severity of gastrointestinal symptoms in rugby players. International Journal of Sports Medicine, 45(04), pp. 323-221. Cinca-Morros, S. and Álvarez-Herms, J. (2024) The importance of maintaining and improving a healthy gut microbiota in athletes as a preventive strategy to improve heat tolerance and acclimatization. Microorganisms, 12(6), p. 1160. Donnan, K., Williams, E. L. and Stanger, N. (2021) The effects of heat exposure during intermittent exercise on physical and cognitive performance among team sport athletes. Perceptual and Motor Skills, 128(1), pp. 439-466. Fassarella, M., Blaak, E. E., Penders, J., Nauta, A., Smidt, H. and Zoetendal, E. G. (2021) Gut microbiome stability and resilience: elucidating the response to perturbations in order to modulate gut health. Gut, 70(3), pp. 595-605. Fessi, M. S., Nouira, S., Dellal, A., Owen, A., Elloumi, M. and Moalla, W. (2016) Changes of the psychophysical state and feeling of wellness of

  BACKGROUND

MeSH Terms

Interventions

Probiotics

Intervention Hierarchy (Ancestors)

Dietary Supplements; Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages

Study Officials

• George Davis, Masters

  Sheffield Hallam University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Lecturer

Model Details: Parallel Randomised Control Trial

Study Record Dates

• First Submitted: July 21, 2025
• First Posted: May 13, 2026
• Study Start: July 25, 2025
• Primary Completion: August 18, 2025
• Study Completion (Estimated): August 15, 2026
• Last Updated: May 13, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will not share

Locations

US (1); GB (1)