Gastrointestinal Symptoms, Menstrual Cycle
Conditions
Brief summary
The goal of this clinical trial is to learn if a postbiotic supplement can reduce stomach and gut symptoms in physically active women. The main questions it aims to answer are: Does the supplement reduce gut symptoms during the menstrual cycle? Does it improve symptoms related to exercise? Researchers will compare the postbiotic supplement to a placebo (a look-alike capsule that contains no active ingredient) to see if the supplement works. Participants will be physically active, premenopausal female athletes. Participants will: Take either the postbiotic supplement or a placebo each day for two menstrual cycles Track their menstrual cycle and training Report gut symptoms using regular questionnaires Provide stool samples to assess gut health This study will help researchers understand whether postbiotic supplements can improve gut health and reduce symptoms that may affect training and performance in female athletes.
Detailed description
Female athletes commonly report gastrointestinal (gut) symptoms, particularly during exercise and at certain phases of the menstrual cycle. These symptoms can negatively affect comfort, training, and performance. Despite this, there is limited research examining strategies to reduce these symptoms in physically active women. Postbiotics are non-living microbial products that may support gut health by improving the function of the gut barrier and influencing the gut microbiota. While previous research suggests that similar products may reduce gut symptoms in clinical and general populations, their effects in female athletes, particularly across the menstrual cycle, are not well understood. This study is a randomized, placebo-controlled clinical trial designed to investigate the effects of daily postbiotic supplementation on gut symptoms in physically active, premenopausal female athletes. Participants will be randomly assigned to receive either a postbiotic supplement (Humiome® Post LB) or a placebo for two consecutive menstrual cycles. Throughout the study, participants will record gut symptoms using validated questionnaires, with a focus on symptoms experienced during menstruation and across the menstrual cycle. Additional measures will include subtypes of gut symptoms (such as abdominal pain, diarrhoea, and constipation), training behaviour, and stool samples to assess gut microbiota composition and diversity. The primary aim is to determine whether postbiotic supplementation reduces overall gut symptom severity during menstruation compared to placebo. Secondary analyses will explore changes in specific symptom types, gut microbiota outcomes, and training-related measures. This research will provide new insight into the role of postbiotic supplementation in supporting gut health in female athletes and may help inform strategies to reduce symptoms that can impact training and performance.
Interventions
DIETARY_SUPPLEMENTPostbiotic
Postbiotic supplement (Humiome® Post LB) administered as two oral capsules daily, providing 340 mg of postbiotic per day. The supplement contains heat-inactivated microbial strains and fermentation products. Participants will take the supplement daily for two consecutive menstrual cycles following a one-cycle placebo run-in phase.
DIETARY_SUPPLEMENTPlacebo
Placebo capsules containing microcrystalline cellulose, matched in appearance to the postbiotic supplement. Participants will take two capsules daily during a one-cycle placebo run-in phase and, if randomized to the placebo group, continue for two additional menstrual cycles.
Sponsors
Liverpool John Moores University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Intervention model description
All participants will complete an initial placebo run-in phase lasting one menstrual cycle. Following this, participants will be randomly assigned to receive either the postbiotic supplement or continue with placebo for two additional menstrual cycles. Outcomes will be compared between groups to assess the effect of the intervention on gastrointestinal symptoms.
Eligibility
Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
1. Female, cisgender, premenopausal. 2. Minimum age 18 years. 3. Regular, natural menstrual cycle (21-35 days in duration), with 9 or more consecutive periods per year, if possible documented with tracker apps, calendars, or other tools 4. Ability to give informed consent. 5. Body mass index (BMI) ≥ 18.5 and \< 24.9 kg/m² 6. Agreeing to maintain lifestyle habits during the study (same dietary and physical activity habits) 7. Having a smartphone and a history of consistent tracking of training and health records via apps. 8. Having regular GI issues during exercise, and during menstruation. During pre-screening, this will be assessed with a shortened GSRS questionnaire, where participants need to have had, in the month preceding pre-screening, the equivalent of at least a score of 2 in a GSRS focus area (diarrhoea, pain, indigestion). 9. No relevant self-reported abnormalities from medical history. 10. Trained athlete (trains at least 3 times per week for more than 1 hour per day and who has been involved in endurance training for at least 2 years in alignment with previous research (Pfeiffer et al., 2010). This will be evaluated by assessing training records (Strava or similar applications, certificates of attendance at athletic events, club membership, etc.). 11. Access to a health-care provider, who can be contacted by the CRO, and who reside in areas with available emergency health services.
Exclusion criteria
1. Individuals who are pregnant, lactating, or plan to become pregnant before study end. 2. Individuals with secondary amenorrhea. 3. Individuals who use hormonal contraceptives during the last 6 months before (and during) the trial. 4. Individuals who are currently participating in another clinical trial or have participated in a trial within the last two months prior to enrolment. 5. Tobacco smokers and vapers. 6. Individuals with acute illnesses. 7. Individuals with a current musculoskeletal injury or one within the last month. 8. Individuals taking probiotic supplements or have taken probiotics two weeks prior to enrolment. 9. Individuals controlling chronic diseases with treatments known to alter the intestinal microbiome or to alter GI symptoms, such as certain pain killers, antacids, proton pump inhibitors, anti-diarrhoeal medication or supplements, and laxatives. 10. Individuals having received antibiotics treatments within three months of trial start. 11. Individuals having planned major changes in lifestyle (i.e. diet, weight loss program, exercise level, travelling) during the duration of the study. 12. Individuals who have hypersensitivity/allergy to any of the components of the test product. 13. Individuals who have planned major elective surgery during the study period.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Gastrointestinal Symptom Severity During Menstruation | At the post menstruation assessment following completion of cycle 4 ~84-147 days depending on individual cycle and menstruation duration | To assess the effect of daily consumption of Humiome® Post LB (HPLB) on menstrual cycle-related gastrointestinal symptoms (total amended Gastrointestinal Symptom Rating Scale scores; aGSRS) during the final intervention menstrual cycle (Phase 3) in physically active, premenopausal female athletes. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Total Gastrointestinal Symptom Rating Scale (GSRS) score assessed weekly across the two intervention menstrual cycles. | Weekly from the start of Cycle 2 through completion of Cycle 4 (up to 147 days from baseline; cycles range 21-35 days | To assess the effect of daily consumption of HPLB on menstrual cycle-related gastrointestinal symptoms (GSRS) during the second intervention menstrual cycle (Phase 2) in physically active, premenopausal female athletes, by comparing the HPLB group to the placebo group. This is a 7-point Likert scale with 1 indicating "no discomfort at all" and 7 indicating "very severe discomfort". |
| Total Gastrointestinal Symptom Rating Scale Score | Weekly from the start of the start of the first intervention cycle (Cycle 2) through completion of the final intervention cycle (Cycle 4), up to 147 days from baseline | Between-group difference (HPLB vs placebo) in total Gastrointestinal Symptom Rating Scale (GSRS) score assessed weekly across the two intervention menstrual cycles. This is a 7-point Likert scale with 1 indicating "no discomfort at all" and 7 indicating "very severe discomfort". |
| GSRS Sub-Category Scores | Weekly from the start of the start of the first intervention cycle (Cycle 2) through completion of the final intervention cycle (Cycle 4), up to 147 days from baseline | Between-group difference (HPLB vs placebo) in Gastrointestinal Symptom Rating Scale (GSRS) sub-category scores assessed weekly across the two intervention menstrual cycles, including reflux, abdominal pain, indigestion, diarrhoea, and constipation. This is a 7-point Likert scale with 1 indicating "no discomfort at all" and 7 indicating "very severe discomfort". |
| Wilson Gastrointestinal Symptom Score | Daily during menstruation on Day 1 (±1 day) of Cycle 2 (phase 2), Cycle 3 and Cycle 4 (phase 3). Up to 147 days from baseline. | Between-group difference (HPLB vs placebo) in Wilson Gastrointestinal Symptom scores recorded daily during menstruation across both intervention cycles. Gastrointestinal symptoms will be rated on a 0-10 Likert scale for that day. The scale has descriptors of "no discomfort," "moderate discomfort," and "unbearable discomfort" at 0, 5, and 10, respectively. |
| Faecal microbial composition | Menstruation on Day 1 (±1 day) of Cycle 2 (phase 2) and Cycle 4 (phase 3). Approximately 28-140 days from baseline depending on individual menstrual cycle duration. | Between-group difference (HPLB vs placebo) in faecal microbial composition at phylum, genus, and species level measured using metagenomic sequencing. |
| Faecal Microbial Diversity | Menstruation on Day 1 (±1 day) of Cycle 2 (phase 2) and Cycle 4 (phase 3). Approximately 28-140 days from baseline depending on individual menstrual cycle duration. | Between-group difference (HPLB vs placebo) in faecal microbial diversity at species level measured using metagenomic sequencing. |
| Faecal Microbial Metabolites | Menstruation on Day 1 (±1 day) of Cycle 2 (phase 2) and Cycle 4 (phase 3). Approximately 28-140 days from baseline depending on individual menstrual cycle duration. | Between-group difference (HPLB vs placebo) in faecal microbial metabolites, including short-chain fatty acids. |
| Adherence to Planned Training | Weekly from the start of the first intervention cycle (Cycle 2) through completion of the final intervention cycle (Cycle 4), up to 147 days from baseline. | Between-group difference (HPLB vs placebo) in adherence to physical activity training schedules, measured as the percentage of planned training sessions completed across the two intervention menstrual cycles. |
| Weekly Duration of Physical Training | Weekly from the start of the first intervention cycle (Cycle 2) through completion of the final intervention cycle (Cycle 4), up to 147 days from baseline. | Between-group difference (HPLB vs placebo) in average weekly minutes of physical training completed across the two intervention menstrual cycles. |
| Weeks With Moderately Severe or Worse Gastrointestinal Symptoms | Weekly across the two intervention menstrual cycles | Between-group difference (HPLB vs placebo) in the number of weeks with moderately severe or worse gastrointestinal symptoms, defined as a GSRS score of 4 or higher in any of the five symptom categories: reflux, abdominal pain, indigestion, diarrhoea, or constipation. |
| Gastrointestinal-Symptom-Free Weeks | Weekly cross the two intervention menstrual cycles | Between-group difference (HPLB vs placebo) in the number of gastrointestinal-symptom-free weeks, defined as a GSRS score of 1 in all five symptom categories: reflux, abdominal pain, indigestion, diarrhoea, and constipation. |
Countries
United Kingdom
Contacts
CONTACTKelsie Johnson, PhD
CONTACTSamantha Moss, PhD
PRINCIPAL_INVESTIGATORKelsie Johnson, PhD
Liverpool John Moores University
Outcome results
None listed