Clinical trial Recruiting at 1 site Interventional Ages 18 to 50

Impact of a fermented dairy protein with prebiotic fiber on gastrointestinal complaints in athletes

Official title: Effect of a Fermented Whey and Fiber Supplement on Digestive Comfort of Recreational Athletes With and Without GI Complaints

Run by Arizona State University · NCT06946017 · Data updated 2026-11-12

This study is testing if a special dairy protein with added fiber can help athletes with stomach issues feel better and improve their overall health.

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Quick facts

Study typeInterventional
Ages18 Years to 50 Years
SexAll
Enrollment114 (estimated)
SponsorArizona State University
Academic / other
Locations1 site (Phoenix, Arizona)
StatusRecruiting
StartedMarch 31, 2025
Main results expectedSeptember 20, 2026
Study endsJune 30, 2027
Registry record updatedNovember 2, 2026
Trial IDNCT06946017 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Ideal candidates are healthy men and women aged 18-50 who are recreational or competitive athletes exercising at least twice a week.

Probably not a fit

Patients who do not meet the inclusion criteria or have moderate GI complaints may not benefit from this study.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This project investigates the effects of a fermented dairy protein with prebiotic fiber supplement on gastrointestinal (GI) complaints and overall well-being in athletes. It consists of two parts: the first part examines carbohydrate malabsorption in athletes without self-reported GI issues through a randomized double-blind crossover design, while the second part focuses on athletes with GI complaints using a randomized double-blind parallel design. Both parts include standardized exercise tests and aim to assess changes in gut microbiota, immune markers, and overall health. The study is designed to provide insights into the relationship between gut health and athletic performance.

Why it matters

Potential benefit: If successful, this study could lead to improved digestive health and quality of life for athletes experiencing GI complaints.

How similar studies have gone: Previous studies have suggested positive outcomes with similar approaches, indicating potential for success in this investigation.

Who can join: the full rules

Show full inclusion / exclusion criteria
Aside from having participants fitting the inclusion and exclusion criteria below, potential participants will be screened using the gastrointestinal symptom rating scale (GSRS). Based on the outcome they will be assigned to the Part I (i.e. no self-reported GI tract issues (GSRS questionnaire score GI complaints, based on GSRS screening with all items scored \<4 (severe) and a total GSRS score ≤25), or Part II (i.e. Severe self-reported GI tract issues (GSRS questionnaire score GI complaints, based on GSRS screening with at least one item scored ≥4 (severe) and a total GSRS score ≥30). If they don't fit these criteria (i.e., having a GSRS score ranging from 26-29) they will be excluded from participation.

Inclusion Criteria:

* Healthy subjects living in the Phoenix area in AZ, USA during the study
* Women/Men aged between 18-50 years (50-50%)
* Recreational competitive and non-competitive athletes (exercise at least 2x per week with a minimal total duration of 2 hours/week)
* BMI value between ≥18.5 and ≤ 30 kg/m2
* No physical limitations due to an injury (i.e., able to perform all activities associated with daily living and exercise in an independent manner).
* Willing to slightly increase their energy intake via a supplement during the study period on daily basis in the morning before breakfast.
* Willing and comfortable to perform multiple physical (stress) tests on a treadmill during the study.
* Participants without any contraindications when scoring the Physical Activity Readiness Questionnaire (PAR-Q+).
* Written informed consent
* For part I: Self-perceived lactose intolerance, and/or omission of dairy products, and/or identifying as Hispanic/Latino or Asian
* For part I: Determined to be lactase non-persistent (LNP) CC genotype by qPCR, and/or positive lactose intolerance test (\>20ppm increase from baseline when 25g of lactose administered)

Exclusion Criteria:

* Users of (sport) supplements containing probiotics and/or prebiotics and those unwilling to temporarily stop use of these supplements at least 3 weeks prior to start of the intervention
* Women who plan to start or stop the use of contraceptives before or during study period
* Women that have additional or worse GI symptoms during their period that can be classified as severe
* Smoking
* Clinical lactose intolerance
* Clinical or self-perceived milk protein allergy
* Diagnosed GI tract disorders or diseases
* Musculoskeletal disorders
* Diagnosed metabolic disorders (such as diabetes)
* Use of any medications known to affect protein metabolism (i.e., corticosteroids, non-steroidal anti-inflammatories, or prescribed acne medications).
* Chronic use of gastric acid suppressing medication or anti-coagulants
* Chronic use of anti-inflammatory medication
* Use of antibiotics the past 0-6 months
* Blood donation in the past 2 months
* (Intending to become) Pregnant/lactating women
* Significant changes in body weight during the past 4 weeks (i.e., due to reduction of body weight through limiting caloric intake, illness,)
* Athletes should not aim to lose bodyweight by reducing energy intake during the study
* For Part I: A hydrogen breath peak of less than 20 ppm over baseline during a lactose tolerance test

Where it's running

  • ASU Health Futures Center
    Phoenix, Arizona, United States
    Recruiting

Study contacts

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.