Gastrointestinal DiscomfortNCT05375487
The Effect of Natural Carbonated Mineral Water Consumption on Gastrointestinal Transit and Gut Microbiota - A Randomized Controlled Trial
A study testing Natural Carbonated Mineral Water and Low Mineral Water in people with Gastrointestinal Discomfort, run by Universidade Nova de Lisboa at 1 site in Portugal.
Trial summary
Gastrointestinal discomfort is a common condition associated with aging, low levels of physical activity, and reduced intake of fibre, water, and magnesium. Several studies have reported a positive association between the consumption of hyper-mineral water containing high levels of bicarbonate, calcium, or magnesium… Read more about this study
- Who is it for?
- Ages 18 to 70 yearsHealthy volunteers can take part
- Conditions the study is for
- Gastrointestinal Discomfort
- What is being tested?
- Natural Carbonated Mineral Water and Low Mineral Water
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 30 participants
- Where
- 1 sitePortugal
- Study dates
- 5 Apr 2023to 20 Nov 2023
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Age between 18 and 70 years
- History of gastrointestinal discomfort
- Not using any laxative drug for 3 days before the screening visit
- Drinking 1.0 ± 0.5 L of water per day
- Accepting and signing the informed consent
Who cannot join
- Treatment or disease (current or past) likely to interfere with evaluation of the study parameters
- Taking antibiotics in the 3 months preceding the recruitment visit
- Taking supplements or any food enriched with or containing bacteria or yeasts likely to have an effect on the gastrointestinal tract, particularly on intestinal transit, digestive comfort, gas production, or the occurrence of abdominal pain, in the 30 days preceding the recruitment visit (these products will also be banned during the study period)
- Subject having an alcohol consumption of more than 3 glasses of wine per day, or 2 glasses of beer per day, or 1 glass of hard liquor per day
- Subject having a coffee consumption greater than 5 cups per day
- Subject with constipation attributable to an organic or anatomical cause (Hirschsprung's disease, hypothyroidism, mental deficiency, psychiatric illness, neurological abnormalities, history of operation of the colon or anus, colorectal cancer, anemia, etc.)
Show all 16Show fewer
- Subject with a history of current gastrointestinal pathology or disorder such as duodenal ulcer, chronic colitis, or chronic inflammatory disease of the gastrointestinal tract (Crohn's disease, ulcerative colitis), celiac disease, or irritable bowel syndrome
- Subject having a history of operation of the digestive tract
- Subject having undergone surgery in the two months preceding the recruitment visit
- Subject having undergone bariatric surgery
- Having participated in a weight loss program (with a 5-10% weight loss) in the last 3 months prior to the recruitment visit
- Body mass index > 35 kg/m²
- Taking supplements of magnesium, vitamins, or other minerals during the study period
- Intake of other carbonated mineral waters beyond the provided water during the study period
- Pregnancy
- Participation in another clinical trial during the last 30 days prior to the recruitment visit
Trial locations and contacts
1 site in 1 country.
Portugal1 site
NOVA Medical School | Faculdade de Ciências Médicas da Universidade NOVA
Lisbon, 1169-056
About this study
Gastrointestinal discomfort is a common condition associated with aging, low levels of physical activity, and reduced intake of fibre, water, and magnesium. Several studies have reported a positive association between the consumption of hyper-mineral water containing high levels of bicarbonate, calcium, or magnesium and improvements in gastrointestinal transit. There is evidence that magnesium and sulphate, individually, exert a laxative effect; however, the impact of other minerals remains limited.
Different mechanisms have been described to explain how the gut microbiota influences gastrointestinal transit. It is important to understand the characteristics of the gut microbiota and to determine whether the intake of hyper-mineral water, a natural source of minerals, can positively modulate it.
The aim of this randomized, placebo-controlled trial is to evaluate the effects of carbonated mineral water consumption on gastrointestinal transit and gut microbiota composition.
- Conditions
- Gastrointestinal Discomfort
- Being tested
- Natural Carbonated Mineral Water, Low Mineral Water
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Natural Carbonated Mineral WaterOther
Participants consume 1000 mL per day of natural carbonated mineral water for 4 weeks, divided into four portions: before breakfast, 30 minutes before lunch, during the afternoon, and 30 minutes before dinner. Any additional water intake, if desired, is provided by the study investigators and consists exclusively of low-mineral water in both study arms. Participants record their total weekly water consumption using an electronic form.
Low Mineral WaterOther
Participants consume 1000 mL per day of low-mineral water for 4 weeks, divided into four portions: before breakfast, 30 minutes before lunch, during the afternoon, and 30 minutes before dinner. Any additional water intake, if desired, is provided by the study investigators and consists exclusively of low-mineral water in both study arms. Participants record their total weekly water consumption using an electronic form.
| Study group | Role | What they receive |
|---|---|---|
| Carbonated Natural Mineral Water | Experimental | Participants consume 1000 mL per day of natural carbonated mineral water throughout the 4-week study period. Receives: Other: Natural Carbonated Mineral Water |
| Low Mineral Water | Placebo comparator | Participants consume 1000 mL per day of low-mineral water throughout the 4-week study period. Receives: Other: Low Mineral Water |
What is being measured
The primary outcome is the main question the study is designed to answer.
Difference between the intervention and control group in the change in gastrointestinal transit from baseline to the end of follow-up (4 weeks).
Change in gastrointestinal transit measured by the percentage of responder subjects defined as a composite score of the two following Rome IV criteria: number of stools ≥ 4 or an increase of 2 stools/week and stools consistency with less than 25% of lumpy to hard stools.
Measured: 4 weeks
Secondary outcomes (8)
Difference between the intervention and control group in the change in stool consistency from baseline to the end of follow-up (4 weeks).
Change in stool consistency measured using Bristol scale.
Measured: 4 weeks
Difference between the intervention and control group in the change in constipation symptoms from baseline to the end of follow-up (4 weeks).
Change in constipation symptoms measured using a validated PAC-SYM questionnaire. PAC-SYM is a 12-item, self-administered questionnaire used to measure severity of symptoms over the past 2 weeks in patients with constipation. Cultural adaptation and linguistic validation of the PAC-SYM for Portugal was performed by Mapi Research.
Measured: 4 weeks
Difference between the intervention and control group in the change in constipation Quality of Life from baseline to the end of follow-up (4 weeks).
Change in constipation Quality of Life measured using a validated PAC-QOL questionnaire. PAC-QOL questionnaire is a 28-item self-administered questionnaire that is being used to measure health-related quality of life (over the past 2 weeks) in patients with chronic constipation. Cultural adaptation and linguistic validation of the PAC-QOL for Portugal was performed by Mapi Research Trust.
Measured: 4 weeks
Difference between the intervention and control group in the change in Perceived Stress Scale from baseline to the end of follow-up (4 weeks).
Change in constipation Perceived Stress Scale measured using a validated Perceived Stress Scale questionnaire. A validated Perceived Stress Scale (PSS) self-administered questionnaire with 13-item will be used to measure perceived stress of respondents during the last month (Portuguese version keeps 13 of the 14 original items). The PSS questionnaire has been demonstrated to have internal consistency, reproducibility, validity, and sensitivity. Cultural adaptation and linguistic validation of the PSS for Portugal was implemented by Pais-Ribeiro \& Marques (2009).
Measured: 4 weeks
Difference between the intervention and control group in the change in gut microbiota from baseline to the end of follow-up (4 weeks).
Bacterial DNA will be extracted from fecal samples. 16SRNA gene will be sequenced by next-generation sequencing (NGS). All the identified bacterial phyla, genus and species will be expressed in percentage.
Measured: 4 weeks
Difference between the intervention and control group in the change in short-chain fatty acid profiling from baseline to the end of follow-up (4 weeks).
Change in short-chain fatty acid profiling evaluated by the faeces concentration of short-chain fatty acids before and after intervention.
Measured: 4 weeks
Difference between the intervention and control group in the change in urinary excretion of minerals from baseline to the end of follow-up (4 weeks).
Change in urinary excretion of minerals evaluated by the K+, Na+, Mg2+ and Ca2+ excretion before and after intervention.
Measured: 4 weeks
Difference between the intervention and control group in the change in urinary pH from baseline to the end of follow-up (4 weeks).
Change in urinary pH evaluated by the urine pH before and after intervention.
Measured: 4 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 May 2022
- Study start5 Apr 2023
- Primary completion25 Oct 2023
- Study completion20 Nov 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Gastrointestinal DiscomfortStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 30 participants (actual)
Sponsor and investigators
- Lead sponsor
- Universidade Nova de Lisboa
- Sponsor type
- University, hospital or other
- Collaborators
- Center for Health Technology and Services Research
- Responsible party
- Sponsor
- Investigators
- Conceição Calhau, PhD, Principal investigator, NOVA Medical School | Faculdade de Ciências Médicas da Universidade NOVA de LisboaAndré Rosário, PhD, Study director, NOVA Medical School | Faculdade de Ciências Médicas da Universidade NOVA de LisboaInês Mota, Study director, NOVA Medical School | Faculdade de Ciências Médicas da Universidade NOVA de Lisboa
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05375487
- Sponsor's protocol ID
- MineralWaterGut
- Status last verified
- Feb 2026
- First submitted
- 11 May 2022
- Last updated
- 17 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data (IPD) from this study will not be publicly shared because the ethics committee has limited their use to the approved research project. However, anonymised partial data sets or summary data may be made available upon reasonable request.
Study at a glance
From the registry record, last updated by the sponsor on 17 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Natural Carbonated Mineral Water Consumption on Gastrointestinal Transit and Gut Microbiota - A Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT05375487
- Acronym / sponsor ID
- MineralWaterGut
- Conditions
- Gastrointestinal Discomfort
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 30 participants (actual)
- Lead sponsor
- Universidade Nova de LisboaUniversity, hospital or other
- Collaborators
- Center for Health Technology and Services Research
- Study start
- 5 Apr 2023 (actual)
- Primary completion
- 25 Oct 2023 (actual)
- Study completion
- 20 Nov 2023 (actual)
- First posted
- 16 May 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Gastrointestinal discomfort is a common condition associated with aging, low levels of physical activity, and reduced intake of fibre, water, and magnesium. Several studies have reported a positive association between the consumption of hyper-mineral water containing high levels of bicarbonate, calcium, or magnesium and improvements in gastrointestinal transit. There is evidence that magnesium and sulphate, individually, exert a laxative effect; however, the impact of other minerals remains limited.
Different mechanisms have been described to explain how the gut microbiota influences gastrointestinal transit. It is important to understand the characteristics of the gut microbiota and to determine whether the intake of hyper-mineral water, a natural source of minerals, can positively modulate it.
The aim of this randomized, placebo-controlled trial is to evaluate the effects of carbonated mineral water consumption on gastrointestinal transit and gut microbiota composition.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Carbonated Natural Mineral Water | Experimental | Other: Natural Carbonated Mineral WaterParticipants consume 1000 mL per day of natural carbonated mineral water throughout the 4-week study period. |
| Low Mineral Water | Placebo comparator | Other: Low Mineral WaterParticipants consume 1000 mL per day of low-mineral water throughout the 4-week study period. |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Age between 18 and 70 years
- History of gastrointestinal discomfort
- Not using any laxative drug for 3 days before the screening visit
- Drinking 1.0 ± 0.5 L of water per day
- Accepting and signing the informed consent
Key exclusion criteria (16 listed)
- Treatment or disease (current or past) likely to interfere with evaluation of the study parameters
- Taking antibiotics in the 3 months preceding the recruitment visit
- Taking supplements or any food enriched with or containing bacteria or yeasts likely to have an effect on the gastrointestinal tract, particularly on intestinal transit, digestive comfort, gas production, or the occurrence of abdominal pain, in the 30 days preceding the recruitment visit (these products will also be banned during the study period)
- Subject having an alcohol consumption of more than 3 glasses of wine per day, or 2 glasses of beer per day, or 1 glass of hard liquor per day
- Subject having a coffee consumption greater than 5 cups per day
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Natural Carbonated Mineral WaterParticipants consume 1000 mL per day of natural carbonated mineral water for 4 weeks, divided into four portions: before breakfast, 30 minutes before lunch, during the afternoon, and 30 minutes before dinner. Any additional water intake, if desired, is provided by the study investigators and consists exclusively of low-mineral water in both study arms. Participants record their total weekly water consumption using an electronic form. | Other | Carbonated Natural Mineral Water |
| Low Mineral WaterParticipants consume 1000 mL per day of low-mineral water for 4 weeks, divided into four portions: before breakfast, 30 minutes before lunch, during the afternoon, and 30 minutes before dinner. Any additional water intake, if desired, is provided by the study investigators and consists exclusively of low-mineral water in both study arms. Participants record their total weekly water consumption using an electronic form. | Other | Low Mineral Water |
Primary outcome
Difference between the intervention and control group in the change in gastrointestinal transit from baseline to the end of follow-up (4 weeks).
Time frame: 4 weeks
Change in gastrointestinal transit measured by the percentage of responder subjects defined as a composite score of the two following Rome IV criteria: number of stools ≥ 4 or an increase of 2 stools/week and stools consistency with less than 25% of lumpy to hard stools.
8 secondary outcomes
Difference between the intervention and control group in the change in stool consistency from baseline to the end of follow-up (4 weeks).
Time frame: 4 weeks
Difference between the intervention and control group in the change in constipation symptoms from baseline to the end of follow-up (4 weeks).
Time frame: 4 weeks
Difference between the intervention and control group in the change in constipation Quality of Life from baseline to the end of follow-up (4 weeks).
Time frame: 4 weeks
Difference between the intervention and control group in the change in Perceived Stress Scale from baseline to the end of follow-up (4 weeks).
Time frame: 4 weeks
Difference between the intervention and control group in the change in gut microbiota from baseline to the end of follow-up (4 weeks).
Time frame: 4 weeks
Difference between the intervention and control group in the change in short-chain fatty acid profiling from baseline to the end of follow-up (4 weeks).
Time frame: 4 weeks
Difference between the intervention and control group in the change in urinary excretion of minerals from baseline to the end of follow-up (4 weeks).
Time frame: 4 weeks
Difference between the intervention and control group in the change in urinary pH from baseline to the end of follow-up (4 weeks).
Time frame: 4 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Feb 2026.
- Individual participant dataSharing planned: No. Individual participant data (IPD) from this study will not be publicly shared because the ethics committee has limited their use to the approved research project. However, anonymised partial data sets or summary data may be made available upon reasonable request.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Conceição Calhau, PhD principal investigator
NOVA Medical School | Faculdade de Ciências Médicas da Universidade NOVA de Lisboa
André Rosário, PhD study director
NOVA Medical School | Faculdade de Ciências Médicas da Universidade NOVA de Lisboa
Inês Mota study director
NOVA Medical School | Faculdade de Ciências Médicas da Universidade NOVA de Lisboa
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Natural Carbonated Mineral Water and Low Mineral Water in people with Gastrointestinal Discomfort, run by Universidade Nova de Lisboa at 1 site in Portugal.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 17 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Portugal. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Difference between the intervention and control group in the change in gastrointestinal transit from baseline to the end of follow-up (4 weeks). (time frame: 4 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Feb 2026.