Intermittent FastingRufaidaNCT07001358
The Rufaida Project: Researching the Impact of Ramadan Fasting on the Gut and Vaginal Microbiome
An observational study of Intermittent Fasting and Gut Microbiome, run by University Hospital, Antwerp at 1 site in Belgium.
Trial summary
The body's systems are deeply connected, but they are often studied separately. A recent large-scale citizen-science project on women's health, called Isala, discovered a group of gut-related bacteria present in the vaginal microbiome. Read more about this study
- Who is it for?
- Ages 18 years and older, women onlyHealthy volunteers can take part
- Conditions the study is for
- Intermittent Fasting, Gut Microbiome, Vaginal Microbiome
- How many people
- 350 participants
- Where
- 1 siteBelgium
- Study dates
- 4 Feb 2025to Feb 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
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 years and older
- Women only
- Healthy volunteers accepted
- Adult, Older adult
Study population: Healthy volunteers participating in Ramadan 2025 will be recruited through various channels. The selected women can join select to join group 1 (n=50) that take biological samples and fill out weekly questionnaires, or group 2 (n=300) that fill out weekly questionnaires.
Who may be able to join
- 18 years or older on the moment of registration
- Female (biological gender)
- Currently living in Belgium
- Sufficient knowledge of the Dutch language
- Participating in Ramadan
- Has signed the informed consent
Who cannot join
- Breastfeeding at the start of and during the study
- Current diagnosis of cancer and/or immunosuppressive therapy in the six months before the study
- Cardiovascular and metabolic conditions (such as diabetes, irritable bowel syndrome, etc.)
- Clinically significant tendency to bleed throughout history;
- Clinically significant abnormalities of the reproductive organs;
- Any other medical condition that, in the judgment of the principal investigator, warrants exclusion from the study;
Show all 11Show fewer
- Use of oral/vaginal antibiotics/antimycotics in the 2 months prior to the study;
- Use of oral/vaginal pre-, pro-, and postbiotics (i.e., supplements in addition to diet) in the 2 weeks before and during the study;
- Ketogenic diet in the 2 weeks before and during the study;
- Vaginal douching during the study;
- Concurrent participation in another clinical trial.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Rufaida Project: Towards a Better Understanding of a Gut-vagina Axis by Investigating the Effects of Ramadan Fasting on Gut and Vaginal Microbial Communities
The body's systems are deeply connected, but they are often studied separately. A recent large-scale citizen-science project on women's health, called Isala, discovered a group of gut-related bacteria present in the vaginal microbiome. This finding supports the idea that gut and vaginal bacteria interact closely, a connection known as the gut-vagina axis. However, it remains unclear whether changes in gut bacteria influence the vaginal microbiome.
This discovery led to an exploration of how diet affects both the gut and vaginal microbiomes. In the gut, bacteria rely on carbohydrates from food, while in the vagina, bacteria feed on glycogen, a sugar stored in the vaginal lining. This glycogen is broken down into smaller sugars, which beneficial Lactobacillus bacteria use for fermentation. Since starch is a major source of these sugars, researchers suspect that a starch-rich diet may support Lactobacillus growth, which in turn promotes vaginal health.
Read more
To test this hypothesis, the Rufaida Project was launched. Ramadan is characterised by a fasting period of approximately one month during which participants abstain from eating between sunrise and sunset. Ramadan provides a unique opportunity to study how fasting affects the microbiome under controlled conditions.
In this study, 50 Muslim women will be asked to provide vaginal and stool samples at eight predetermined time points-before, during, and after Ramadan. These samples will be analysed using 16S rRNA amplicon sequencing to determine bacterial composition. Comparative analysis will be conducted between samples across different time points and anatomical sites. The objective is to understand how fasting and dietary changes influence the gut and vaginal microbiomes, and whether gut bacteria play a role in shaping vaginal health. Additionally, participants will complete weekly health questionnaires. An additional study group of up to 300 Muslim women will complete weekly questionnaires without providing biological samples.
This research could improve understanding of the links between diet, gut health, and vaginal health, potentially leading to new strategies for enhancing women's well-being through nutrition.
Read the detailed description
The objective of this observational study is to examine the impact of fasting on the vaginal and gut microbiomes. The study population comprises healthy female volunteers of reproductive age who participate in Ramadan 2025. Participants will be enrolled in one of two study groups based upon their own selection.
Group One will include up to 50 women that provide vaginal and stool samples over a period of eight weeks: two weeks prior to Ramadan, throughout the four weeks of Ramadan, and two weeks following Ramadan. Sampling kits will be accompanied by an instruction brochure detailing standardized procedures to ensure reliable and consistent sample collection. In addition, participants in this group will complete a weekly questionnaire assessing general, mental, vaginal, gut, sexual, and reproductive health.
Group Two will consist of 300 women that complete the same weekly health questionnaire but will not provide biological samples.
- Conditions
- Intermittent Fasting, Gut Microbiome, Vaginal Microbiome
- Keywords
- Vaginal microbiome, Gut microbiome, Intermittent fasting, Ramadan, Gut-vagina axis, Citizen science
- Medical subject headings
- Intermittent Fasting
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Women participating in Ramadan | Healthy volunteers that plan on intermittent fasting during the month of Ramadan 2025. No food or drink will be consumed from sunrise until sundown |
What is being measured
The primary outcome is the main question the study is designed to answer.
Characterizing the gut and vaginal microbiome in relation to dietary components and meal frequency during ramadan using 16S rRNA sequencing
To investigate the potential influence of dietary components and meal frequency on the gut and vaginal microbiome, vaginal and stool samples will be collected from participants before, during, and after a period of intermittent fasting (Ramadan). Bacterial community composition will be determined using 16S rRNA amplicon sequencing by Illumina MiSeq analysis. Bioinformatic tools will be employed to assess taxonomic profiles across different time points and anatomical sites. Particular attention will be given to correlations between gut- and vaginal-associated microbial taxa, with the aim of identifying bacterial signatures potentially shaped by dietary changes and fasting patterns. The analysis will further explore whether specific gut microbiota are associated with the presence or modulation of vaginal microbial communities, with a focus on health-promoting taxa such as Lactobacillus species.
Measured: up to 4 years
Secondary outcomes (2)
Determining changes in psychological well-being during Ramadan through longitudinal questionnaires
Participants will complete comprehensive questionnaires at eight predetermined time points before, during, and after Ramadan. These questionnaires are designed to evaluate various aspects of mental health and social connectedness, including feelings of togetherness with family, community, and the surrounding environment. The researchers will specifically focus on the temporal changes in psychological well-being and social cohesion associated with the fasting period.
Measured: Up to 4 years
Characterization of metabolite profiles in vaginal and stool samples before, during, and after Ramadan fasting
This study involves longitudinal analysis of vaginal and stool samples collected at baseline, during, and after a period of intermittent fasting (Ramadan). Metabolomic profiling will be performed to identify and quantify bacterial metabolites, with particular focus on changes associated with dietary modifications during fasting. Comparative analyses between vaginal and gut samples will be conducted to investigate potential correlations between microbial communities and their metabolic outputs across anatomical sites. Additionally, the research will emphasize the role of health-promoting microorganisms, including Lactobacillus and Saccharomyces species, in shaping the metabolite landscape.
Measured: Up to 4 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Jun 2025
- Study start4 Feb 2025
- Primary completion30 May 2025 (estimated)
- Study completionFeb 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Intermittent FastingStudies of the same condition, open and under way.
- More trials run by University Hospital, AntwerpThe sponsor's other registered studies.
- 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
- Observational
- Observational model
- Cohort
- Time perspective
- Other
- Enrolment
- 350 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Antwerp
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Sarah Lebeer, Professor, Principal investigator, Universiteit Antwerpen
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07001358
- Sponsor's protocol ID
- BUN B3002024000242
- Acronym
- Rufaida
- Status last verified
- Feb 2025
- First submitted
- 25 Mar 2025
- Last updated
- 3 Jun 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: The metadata of participants in the study will be made available in a restricted access repository. * For samples and data sharing, the researchers will work with the legal department to establish Material/Data Transfer Agreements. * Sequencing data are available at the European Nucleotide Archive. * Physical samples are their origin will be stored at the decentral hub of the Antwerp biobank. * Concerning non-identifiable sample meta-data that the researchers will use in analysis and will later be published will be put available with access control via the European Genome-Phenome Archive (EGA), where data can be accessed as described upon agreeing to the harmonized Data Access Agreement (developed by the European Union standards for in silico models for personalized medicine EU-STANDS4PM, https://doi.org/10.6084/m9.figshare.23904300).
Study at a glance
From the registry record, last updated by the sponsor on 3 Jun 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Rufaida Project: Towards a Better Understanding of a Gut-vagina Axis by Investigating the Effects of Ramadan Fasting on Gut and Vaginal Microbial Communities
- ClinicalTrials.gov ID
- NCT07001358
- Acronym / sponsor ID
- Rufaida / BUN B3002024000242
- Conditions
- Intermittent Fasting, Gut Microbiome, Vaginal Microbiome
- Keywords
- Vaginal microbiome, Gut microbiome, Intermittent fasting, Ramadan, Gut-vagina axis, Citizen science
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 350 participants (estimated)
- Lead sponsor
- University Hospital, AntwerpUniversity, hospital or other
- Study start
- 4 Feb 2025 (actual)
- Primary completion
- 30 May 2025 (estimated)
- Study completion
- Feb 2026 (estimated)
- First posted
- 3 Jun 2025 (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.
The body's systems are deeply connected, but they are often studied separately. A recent large-scale citizen-science project on women's health, called Isala, discovered a group of gut-related bacteria present in the vaginal microbiome. This finding supports the idea that gut and vaginal bacteria interact closely, a connection known as the gut-vagina axis. However, it remains unclear whether changes in gut bacteria influence the vaginal microbiome.
This discovery led to an exploration of how diet affects both the gut and vaginal microbiomes. In the gut, bacteria rely on carbohydrates from food, while in the vagina, bacteria feed on glycogen, a sugar stored in the vaginal lining. This glycogen is broken down into smaller sugars, which beneficial Lactobacillus bacteria use for fermentation. Since starch is a major source of these sugars, researchers suspect that a starch-rich diet may support Lactobacillus growth, which in turn promotes vaginal health.
To test this hypothesis, the Rufaida Project was launched. Ramadan is characterised by a fasting period of approximately one month during which participants abstain from eating between sunrise and sunset. Ramadan provides a unique opportunity to study how fasting affects the microbiome under controlled conditions.
In this study, 50 Muslim women will be asked to provide vaginal and stool samples at eight predetermined time points-before, during, and after Ramadan. These samples will be analysed using 16S rRNA amplicon sequencing to determine bacterial composition. Comparative analysis will be conducted between samples across different time points and anatomical sites. The objective is to understand how fasting and dietary changes influence the gut and vaginal microbiomes, and whether gut bacteria play a role in shaping vaginal health. Additionally, participants will complete weekly health questionnaires. An additional study group of up to 300 Muslim women will complete weekly questionnaires without providing biological samples.
This research could improve understanding of the links between diet, gut health, and vaginal health, potentially leading to new strategies for enhancing women's well-being through nutrition.
Detailed description
The objective of this observational study is to examine the impact of fasting on the vaginal and gut microbiomes. The study population comprises healthy female volunteers of reproductive age who participate in Ramadan 2025. Participants will be enrolled in one of two study groups based upon their own selection.
Group One will include up to 50 women that provide vaginal and stool samples over a period of eight weeks: two weeks prior to Ramadan, throughout the four weeks of Ramadan, and two weeks following Ramadan. Sampling kits will be accompanied by an instruction brochure detailing standardized procedures to ensure reliable and consistent sample collection. In addition, participants in this group will complete a weekly questionnaire assessing general, mental, vaginal, gut, sexual, and reproductive health.
Group Two will consist of 300 women that complete the same weekly health questionnaire but will not provide biological samples.
Study design
- Observational model
- Cohort
- Time perspective
- Other
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Women participating in Ramadan | – | –Healthy volunteers that plan on intermittent fasting during the month of Ramadan 2025. No food or drink will be consumed from sunrise until sundown |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Healthy volunteers participating in Ramadan 2025 will be recruited through various channels. The selected women can join select to join group 1 (n=50) that take biological samples and fill out weekly questionnaires, or group 2 (n=300) that fill out weekly questionnaires.
Key inclusion criteria (6 listed)
- 18 years or older on the moment of registration
- Female (biological gender)
- Currently living in Belgium
- Sufficient knowledge of the Dutch language
- Participating in Ramadan
Key exclusion criteria (11 listed)
- Breastfeeding at the start of and during the study
- Current diagnosis of cancer and/or immunosuppressive therapy in the six months before the study
- Cardiovascular and metabolic conditions (such as diabetes, irritable bowel syndrome, etc.)
- Clinically significant tendency to bleed throughout history;
- Clinically significant abnormalities of the reproductive organs;
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Characterizing the gut and vaginal microbiome in relation to dietary components and meal frequency during ramadan using 16S rRNA sequencing
Time frame: up to 4 years
To investigate the potential influence of dietary components and meal frequency on the gut and vaginal microbiome, vaginal and stool samples will be collected from participants before, during, and after a period of intermittent fasting (Ramadan). Bacterial community composition will be determined using 16S rRNA amplicon sequencing by Illumina MiSeq analysis. Bioinformatic tools will be employed to assess taxonomic profiles across different time points and anatomical sites. Particular attention will be given to correlations between gut- and vaginal-associated microbial taxa, with the aim of identifying bacterial signatures potentially shaped by dietary changes and fasting patterns. The analysis will further explore whether specific gut microbiota are associated with the presence or modulation of vaginal microbial communities, with a focus on health-promoting taxa such as Lactobacillus species.
2 secondary outcomes
Determining changes in psychological well-being during Ramadan through longitudinal questionnaires
Time frame: Up to 4 years
Characterization of metabolite profiles in vaginal and stool samples before, during, and after Ramadan fasting
Time frame: Up to 4 years
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Jun 2025.
- Webpage about the study for participantsLink provided by the sponsor.
- Blogpost explaining the study and studygroups to possible participantsLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. The metadata of participants in the study will be made available in a restricted access repository. * For samples and data sharing, the researchers will work with the legal department to establish Material/Data Transfer Agreements. * Sequencing data are available at the European Nucleotide Archive. * Physical samples are their origin will be stored at the decentral hub of the Antwerp biobank. * Concerning non-identifiable sample meta-data that the researchers will use in analysis and will later be published will be put available with access control via the European Genome-Phenome Archive (EGA), where data can be accessed as described upon agreeing to the harmonized Data Access Agreement (developed by the European Union standards for in silico models for personalized medicine EU-STANDS4PM, https://doi.org/10.6084/m9.figshare.23904300).
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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.
Sarah Lebeer, Professor principal investigator
Universiteit Antwerpen
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Intermittent Fasting and Gut Microbiome, run by University Hospital, Antwerp at 1 site in Belgium.
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 6 inclusion and 11 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: under way, not looking for participants, as of the sponsor's last update on 3 Jun 2025. 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 Belgium. 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. 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?
This study is still under way. Results are not available in the source record yet.
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?
Characterizing the gut and vaginal microbiome in relation to dietary components and meal frequency during ramadan using 16S rRNA sequencing (time frame: up to 4 years). 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 3 Jun 2025.