Effects of dietary supplements and nutrition on intestinal bacteria in healthy women and women with recurrent urinary tract infections

ISRCTN	ISRCTN44865878
DOI	https://doi.org/10.1186/ISRCTN44865878
Sponsors	S.C. HOLOMED NUTRITION S.R.L., Universitatea de Medicină, Farmacie, Științe și Tehnologie „George Emil Palade” din Târgu Mureș
Funders	S.C. HOLOMED NUTRITION S.R.L., Universitatea de Medicină, Farmacie, Științe și Tehnologie "George Emil Palade" din Târgu Mureș

Submission date: 02/11/2026
Registration date: 02/11/2026
Last edited: 02/11/2026

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Digestive System

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Record updated in last year

Plain English summary of protocol

Not provided at time of registration

Contact information

Mrs Mirela-Ioana Pribac
Principal investigator

Str. Agricultorilor nr. 30 B
Targu Mures
540272
Romania

Phone	+40743933387
Email	mirela.pribac@holomed.ro

Prof Adrian Man
Scientific

George Emil Palade University of Medicine, Pharmacy, Science and Technology of Târgu Mureș, 38 Gheorghe Marinescu Street
Targu Mires
540142
Romania

ORCID ID	0000-0001-5281-0601
Phone	+40745 350520
Email	adrian.man@umfst.ro

Dr Florina Ruta
Public

George Emil Palade University of Medicine, Pharmacy, Science and Technology of Târgu Mureș, 38 Gheorghe Marinescu Street
Targu Mures
540142
Romania

ORCID ID	0000-0001-5715-5220
Phone	+40752332593
Email	florinaruta@umfst.ro

Study information

Primary study design	Interventional
Allocation	N/A: single arm study
Masking	Open (masking not used)
Control	Uncontrolled
Assignment	Single
Purpose	Basic science
Scientific title	Intestinal microbiota modulation following a combined essential oil–caprylic acid and synbiotic intervention in healthy women and women with recurrent urinary tract infections: a prospective, non-randomized, single-arm clinical study
Study objectives	Primary objective: To evaluate changes in selected cultivable intestinal microbial populations following a three-month combined intervention with an essential oil–caprylic acid formulation, a multi-strain synbiotic, and dietary and hygiene recommendations in healthy premenopausal women and women with a history of recurrent urinary tract infections (rUTIs) Secondary objectives: 1. To compare the direction and magnitude of microbiological changes between the healthy and rUTI cohorts 2. To investigate changes in selected potentially pathogenic and commensal intestinal bacterial populations following the intervention 3. To explore whether baseline clinical status (healthy versus rUTI) is associated with differential microbiological responsiveness 4. To assess participant-reported gastrointestinal symptoms, intervention adherence, and tolerability, as documented through study questionnaires
Ethics approval(s)	Approved 28/02/2024, Research Ethics Committee, Faculty of Medicine and Pharmacy, University of Oradea (10 Piața 1 Decembrie Street, Faculty of Medicine and Pharmacy, University of Oradea, Oradea, 410073, Romania; +40259408559; fmf@uoradea.ro), ref: CEFMF/1
Health condition(s) or problem(s) studied	Comparison of intestinal microbiota composition and dysbiosis in premenopausal women, including healthy women and women with a history of recurrent urinary tract infections
Intervention	This prospective, longitudinal, open-label, non-randomized, single-arm interventional clinical study involved two predefined cohorts of premenopausal women aged 18–45 years: healthy women without a history of urinary tract infections and otherwise healthy women with recurrent urinary tract infections (rUTIs). Both cohorts received the same combined intervention for three months. Intervention components GX Assist® (dōTERRA International LLC, Pleasant Grove, UT, USA): a dietary supplement containing caprylic acid and essential oils of oregano, tea tree, lemon, lemongrass, peppermint, and thyme. PB Restore™ ProBiome Complex (dōTERRA International LLC, Pleasant Grove, UT, USA): a synbiotic formulation providing approximately 18 × 10⁹ colony-forming units (CFU) from 24 active cultures representing 22 bacterial species per capsule, together with fructooligosaccharides (FOS), a heat-inactivated postbiotic strain, and a defined bacteriophage blend. Dietary and hygiene recommendations: participants received nutritional and behavioral guidance throughout the intervention period, including measures aimed at supporting intestinal health and reducing modifiable risk factors associated with recurrent urinary tract infections. Study procedures At baseline, participants completed medical, nutritional, lifestyle, gastrointestinal health, and urinary tract infection history questionnaires. Stool samples were collected and analyzed at Bioclinica Laboratories, Romania, using laboratory-based assessment of selected cultivable intestinal microbial populations. Following the three-month intervention, stool microbiota analysis was repeated within approximately 14 days of intervention completion, using the same laboratory assessment approach. Participant adherence, tolerability, and self-reported effects were assessed through study questionnaires. Changes in microbial populations were evaluated within each cohort and compared between the healthy and rUTI cohorts. No randomization, placebo, untreated control group, or crossover assignment was implemented.
Intervention type	Supplement
Primary outcome measure(s)	Selected cultivable intestinal microbial populations measured using quantitative culture-based stool microbiological analysis (intestinal dysbiosis test) performed at Bioclinica Laboratories, Romania, with laboratory-reported bacterial abundance measures at baseline (before intervention) and post-intervention (within 14 days after completion of the three-month supplementation protocol)
Key secondary outcome measure(s)	Laboratory-derived intestinal Flora Index measured using the unitless Flora Index score reported by GANZIMMUN Diagnostics, with laboratory-defined dysbiosis categories (1–5: mild; 6–12: intermediate; greater than 12: pronounced, at baseline and within 14 days after completion of the three-month intervention Faecal pH measured using the laboratory's stool analysis method and reported on the unitless pH scale, at baseline and within 14 days after completion of the three-month intervention
Completion date	16/03/2026

Eligibility

Participant type(s)
Age group	Adult
Lower age limit	18 Years
Upper age limit	45 Years
Sex	Female
Target sample size at registration	140
Total final enrolment	173
Key inclusion criteria	1. Female participants aged 18–45 years 2. Premenopausal status, defined as at least 10 menstrual periods per year 3. Provision of written informed consent prior to study participation 4. Otherwise healthy women belonging to one of two predefined clinical cohorts: 4.1. Healthy cohort: women without a history of urinary tract infections. 4.2. rUTI cohort: women with a history of recurrent urinary tract infections, defined as at least two episodes within the preceding six months or at least three episodes within the preceding 12 months 5. Absence of chronic medical conditions 6. No ongoing medication or other dietary supplement use at enrolment, or a minimum 14-day interval since previous use of any over-the-counter sporadic medication or supplement, as specified in the study protocol
Key exclusion criteria	1. Recurrent urinary tract infections secondary to underlying medical conditions 2. Chronic diseases, including diabetes mellitus, oncological or hematological disorders, autoimmune diseases, gastrointestinal disorders, or malabsorption syndromes 3. Current medication or dietary supplement use, or use within the preceding 14 days 4. Pregnancy 5. Known allergies relevant to study participation 6. Failure to provide written informed consent
Date of first enrolment	01/03/2024
Date of final enrolment	27/11/2025

Locations

Countries of recruitment

Romania

Study participating centres

Results and Publications

Individual participant data (IPD) Intention to share	No

Editorial Notes

02/11/2026: Study’s existence confirmed by the Research Ethics Committee, Faculty of Medicine and Pharmacy, University of Oradea, Romania.