Environmental ExposureAFCRO202NCT07846371
Effect of a Dietary Supplement Versus Placebo on Serum PFAS Levels in Male Firefighters
A study testing Streptococcus salivarius 46-SL1 in people with Environmental Exposure and PFAS Exposure, run by Cambiotics ApS at 1 site in United States.
Trial summary
This study is designed to evaluate the effect of a probiotic dietary supplement containing Streptococcus salivarius on serum PFAS levels in male firefighters with documented occupational PFAS exposure, following twice-daily use over a 12-week period. Read more about this study
- Who is it for?
- Ages 18 years and older, men onlyHealthy volunteers can take part
- Conditions the study is for
- Environmental Exposure, PFAS Exposure
- What is being tested?
- Streptococcus salivarius 46-SL1
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 70 participants
- Where
- 1 siteUnited States
- Study dates
- 8 Oct 2026to 1 Nov 2027
- Phase
- Interventional
- 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
- Men only
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Able to give written informed consent
- Male firefighter with previous career exposure to PFAS
- BMI between 18.5 and 35 kg/m²
- Serum PFOS level ≥5 ng/mL at screening
- Willing to consume the study product daily for the duration of the study
Who cannot join
- History of drug and/or alcohol abuse (>15 standard drinks per week)
- Food allergy, intolerance or dietary restriction that, in the opinion of the investigator, would preclude consumption of the study product
- Blood donation within the past 3 months
- Current smoker of >20 cigarettes per day, or former smoker with a history of ≥20 cigarettes per day who quit within 6 months prior to Visit 1
- Any significant acute or chronic health condition that would prevent participation, pose a risk, or confound interpretation of results, including: diagnosed gastrointestinal disorders (irritable bowel syndrome, inflammatory bowel disease, Crohn's disease, ulcerative colitis, coeliac disease, or other chronic diarrhoeal disorders); uncontrolled medical conditions; history of chronic kidney or liver disease; chronic inflammatory or autoimmune disease; history of gastrointestinal surgery; hospitalisation within the past 3 months
- Current or recent (past 12 weeks) use of medications affecting bile acid metabolism (e.g. bile acid sequestrants, fibrates) or antibiotics
Show all 10Show fewer
- Current or recent (past 4 weeks) use of supplements affecting gut microbiota (prebiotics, probiotics, postbiotics, fibres, synbiotics), detoxification pathways (milk thistle, N-acetylcysteine, glutathione) or bile acid metabolism (e.g. psyllium husk)
- Current or recent (past 2 weeks) consumption of prohibited foods, including probiotic yoghurts
- Considered by the investigator unlikely to comply with study requirements
- Current participation in another clinical study, or insufficient time elapsed since a previous experimental study
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Atlantia Clinical Trials
Chicago, Illinois, 60611
Abigail O'Mahony, +1 312 535-9440, aomahoney@atlantiatrials.com
sboetto@atlantiatrials.com
About this study
Official title: A Randomized, Double-Blind, Placebo-Controlled, Cross-Over Pilot Study Evaluating a Dietary Supplement Supporting Natural Elimination Processes in Male Firefighters
This study is designed to evaluate the effect of a probiotic dietary supplement containing Streptococcus salivarius on serum PFAS levels in male firefighters with documented occupational PFAS exposure, following twice-daily use over a 12-week period.
Read the detailed description
This randomized, placebo-controlled, double-blind, crossover pilot study will use serum PFAS measurements, questionnaires and stool sample analyses to evaluate changes in PFAS levels, gastrointestinal symptoms and fatigue with a probiotic dietary supplement compared to a placebo. Each crossover period will last 12 weeks, separated by a four-week washout period. The study will consist of eight study visits: Screening Visit, Period 1 Baseline Visit (Day 0), Day 42 Call, Period 1 Day 84 Visit, Day 98 Call, Period 2 Baseline Visit (Day 112), Day 156 Call, and Period 2 Day 196 Visit.
- Conditions
- Environmental Exposure, PFAS Exposure
- Being tested
- Streptococcus salivarius 46-SL1, Placebo
- Keywords
- Cross-over study, Serum PFAS levels, Gut Microbiome, Streptococcus salivarius, Dietary Supplement, Probiotic, Occupational Exposure, Firefighters, Forever Chemicals, Per- and Polyfluoroalkyl Substances
- Medical subject headings
- Progressive Encephalomyelitis with Rigidity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Streptococcus salivarius 46-SL1Dietary supplement
One capsule (~400 mg live probiotic) consumed twice daily with water, in the morning with breakfast and with the evening meal, for 84 days.
PlaceboDietary supplement
Matching placebo capsule containing microcrystalline cellulose, magnesium stearate and silicon dioxide, consumed twice daily with water for 84 days.
| Study group | Role | What they receive |
|---|---|---|
| Sequence A: Study Product then Placebo | Experimental | Participants consume the probiotic dietary supplement (one capsule twice daily) for 84 days, followed by a 28-day washout, then placebo (one capsule twice daily) for 84 days. Receives: Dietary Supplement: Streptococcus salivarius 46-SL1; Dietary Supplement: Placebo |
| Sequence B: Placebo then Study Product | Placebo comparator | Participants consume placebo (one capsule twice daily) for 84 days, followed by a 28-day washout, then the probiotic dietary supplement (one capsule twice daily) for 84 days. Receives: Dietary Supplement: Streptococcus salivarius 46-SL1; Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in serum linear perfluorooctane sulfonic acid (n-PFOS)
Change in serum n-PFOS concentration (ng/mL) from baseline to end of each 84-day intervention period, comparing the dietary supplement with placebo.
Measured: Baseline (Day 0) to Day 84 of each intervention period
Secondary outcomes (4)
Change in pre-specified serum PFAS levels
Change in serum concentrations (ng/mL) of linear PFOA, branched PFOA, PFDoDA, PFUnDA, branched PFOS and PFNA from baseline to end of each 84-day intervention period, comparing the dietary supplement with placebo.
Measured: Baseline (Day 0) to Day 84 of each intervention period
Change in composite serum PFAS measure
Change in a composite PFAS measure calculated as the sum of serum PFOS, PFNA and PFDA (ng/mL) from baseline to end of each 84-day intervention period, comparing the probiotic dietary supplement with placebo.
Measured: Baseline (Day 0) to Day 84 of each intervention period
Change in gastrointestinal symptoms (GSRS)
Change in Gastrointestinal Symptom Rating Scale (GSRS) total score and the five subscale scores (reflux, abdominal pain, indigestion, diarrhoea, constipation).
Measured: Baseline (Day 0) to Day 84 of each intervention period
Change in fatigue (MFIS)
Change in Modified Fatigue Impact Scale (MFIS) total score, a 21-item self-report measure of the impact of fatigue on physical, cognitive and psychosocial functioning.
Measured: Baseline (Day 0) to Day 84 of each intervention period
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Sep 2026
- Study start8 Oct 2026
- Primary completion1 Nov 2027 (estimated)
- Study completion1 Nov 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Environmental ExposureStudies 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Two-period, two-sequence crossover. Participants are randomized 1:1 to the order of study product and placebo, with each 84-day intervention period separated by a 28-day washout.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 70 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Cambiotics ApS
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Atlantia Food Clinical Trials
- Responsible party
- Sponsor
- Investigators
- Klavs Kirk, Study director, Cambiotics ApSStacey Boetto, DNP, FNP-C, Principal investigator, Atlantia Food Clinical TrialsEmilie Glad Bak, PhD, Study director, Cambiotics ApS
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07846371
- Sponsor's protocol ID
- CB-AFCRO202-2026-10
- Acronym
- AFCRO202
- Status last verified
- Oct 2026
- First submitted
- 23 Sep 2026
- Last updated
- 8 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared, as participant consent does not cover external data sharing and the dataset contains commercially confidential information. Aggregate results will be reported.
Publications
Lindell AE, Griesshammer A, Michaelis L, Papagiannidis D, Ochner H, Kamrad S, Guan R, Blasche S, Ventimiglia LN, Ramachandran B, Ozgur H, Zelezniak A, Beristain-Covarrubias N, Yam-Puc JC, Roux I, Barron LP, Richardson AK, Martin MG, Benes V, Morone N, Thaventhiran JED, Bharat TAM, Savitski MM, Maier L, Patil KR. Human gut bacteria bioaccumulate per- and polyfluoroalkyl substances. Nat Microbiol. 2025 Jul;10(7):1630-1647. doi: 10.1038/s41564-025-02032-5. Epub 2025 Jul 1.
PubMed 40595288
Study at a glance
From the registry record, last updated by the sponsor on 8 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomized, Double-Blind, Placebo-Controlled, Cross-Over Pilot Study Evaluating a Dietary Supplement Supporting Natural Elimination Processes in Male Firefighters
- ClinicalTrials.gov ID
- NCT07846371
- Acronym / sponsor ID
- AFCRO202 / CB-AFCRO202-2026-10
- Conditions
- Environmental Exposure, PFAS Exposure
- Keywords
- Cross-over study, Serum PFAS levels, Gut Microbiome, Streptococcus salivarius, Dietary Supplement, Probiotic, Occupational Exposure, Firefighters
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 70 participants (estimated)
- Lead sponsor
- Cambiotics ApSIndustry (pharma, biotech, devices)
- Collaborators
- Atlantia Food Clinical Trials
- Study start
- 8 Oct 2026 (actual)
- Primary completion
- 1 Nov 2027 (estimated)
- Study completion
- 1 Nov 2027 (estimated)
- First posted
- 29 Sep 2026 (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.
This study is designed to evaluate the effect of a probiotic dietary supplement containing Streptococcus salivarius on serum PFAS levels in male firefighters with documented occupational PFAS exposure, following twice-daily use over a 12-week period.
Detailed description
This randomized, placebo-controlled, double-blind, crossover pilot study will use serum PFAS measurements, questionnaires and stool sample analyses to evaluate changes in PFAS levels, gastrointestinal symptoms and fatigue with a probiotic dietary supplement compared to a placebo. Each crossover period will last 12 weeks, separated by a four-week washout period. The study will consist of eight study visits: Screening Visit, Period 1 Baseline Visit (Day 0), Day 42 Call, Period 1 Day 84 Visit, Day 98 Call, Period 2 Baseline Visit (Day 112), Day 156 Call, and Period 2 Day 196 Visit.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Two-period, two-sequence crossover. Participants are randomized 1:1 to the order of study product and placebo, with each 84-day intervention period separated by a 28-day washout.
| Arm | Type | Receives |
|---|---|---|
| Sequence A: Study Product then Placebo | Experimental | Dietary Supplement: Streptococcus salivarius 46-SL1, Dietary Supplement: PlaceboParticipants consume the probiotic dietary supplement (one capsule twice daily) for 84 days, followed by a 28-day washout, then placebo (one capsule twice daily) for 84 days. |
| Sequence B: Placebo then Study Product | Placebo comparator | Dietary Supplement: Streptococcus salivarius 46-SL1, Dietary Supplement: PlaceboParticipants consume placebo (one capsule twice daily) for 84 days, followed by a 28-day washout, then the probiotic dietary supplement (one capsule twice daily) for 84 days. |
Who may qualify
- Ages
- 18 years and older
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Able to give written informed consent
- Male firefighter with previous career exposure to PFAS
- BMI between 18.5 and 35 kg/m²
- Serum PFOS level ≥5 ng/mL at screening
- Willing to consume the study product daily for the duration of the study
Key exclusion criteria (10 listed)
- History of drug and/or alcohol abuse (>15 standard drinks per week)
- Food allergy, intolerance or dietary restriction that, in the opinion of the investigator, would preclude consumption of the study product
- Blood donation within the past 3 months
- Current smoker of >20 cigarettes per day, or former smoker with a history of ≥20 cigarettes per day who quit within 6 months prior to Visit 1
- Any significant acute or chronic health condition that would prevent participation, pose a risk, or confound interpretation of results, including: diagnosed gastrointestinal disorders (irritable bowel syndrome, inflammatory bowel disease, Crohn's disease, ulcerative colitis, coeliac disease, or other chronic diarrhoeal disorders); uncontrolled medical conditions; history of chronic kidney or liver disease; chronic inflammatory or autoimmune disease; history of gastrointestinal surgery; hospitalisation within the past 3 months
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 |
|---|---|---|
| Streptococcus salivarius 46-SL1One capsule (~400 mg live probiotic) consumed twice daily with water, in the morning with breakfast and with the evening meal, for 84 days. | Dietary supplement | Sequence A: Study Product then Placebo, Sequence B: Placebo then Study Product |
| PlaceboMatching placebo capsule containing microcrystalline cellulose, magnesium stearate and silicon dioxide, consumed twice daily with water for 84 days. | Dietary supplement | Sequence A: Study Product then Placebo, Sequence B: Placebo then Study Product |
Primary outcome
Change in serum linear perfluorooctane sulfonic acid (n-PFOS)
Time frame: Baseline (Day 0) to Day 84 of each intervention period
Change in serum n-PFOS concentration (ng/mL) from baseline to end of each 84-day intervention period, comparing the dietary supplement with placebo.
4 secondary outcomes
Change in pre-specified serum PFAS levels
Time frame: Baseline (Day 0) to Day 84 of each intervention period
Change in composite serum PFAS measure
Time frame: Baseline (Day 0) to Day 84 of each intervention period
Change in gastrointestinal symptoms (GSRS)
Time frame: Baseline (Day 0) to Day 84 of each intervention period
Change in fatigue (MFIS)
Time frame: Baseline (Day 0) to Day 84 of each intervention period
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 8 Oct 2026.
- Background: PubMed 40595288Lindell AE, Griesshammer A, Michaelis L, Papagiannidis D, Ochner H, Kamrad S, Guan R, Blasche S, Ventimiglia LN, Ramachandran B, Ozgur H, Zelezniak A, Beristain-Covarrubias N, Yam-Puc JC, Roux I, Barron LP, Richardson AK, Martin MG, Benes V, Morone N, Thaventhiran JED, Bharat TAM, Savitski MM, Maier L, Patil KR. Human gut bacteria bioaccumulate per- and polyfluoroalkyl substances. Nat Microbiol. 2025 Jul;10(7):1630-1647. doi: 10.1038/s41564-025-02032-5. Epub 2025 Jul 1.
- Individual participant dataSharing planned: No. Individual participant data will not be shared, as participant consent does not cover external data sharing and the dataset contains commercially confidential information. Aggregate results will be reported.
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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.
Klavs Kirk study director
Cambiotics ApS
Stacey Boetto, DNP, FNP-C principal investigator
Atlantia Food Clinical Trials
Emilie Glad Bak, PhD study director
Cambiotics ApS
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Streptococcus salivarius 46-SL1 in people with Environmental Exposure and PFAS Exposure, run by Cambiotics ApS at 1 site in United States.
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 10 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: looking for participants now, as of the sponsor's last update on 8 Oct 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 United States. 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?
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?
Contact Abigail O'Mahony, Operations Manager (+1 312 535-9440, aomahoney@atlantiatrials.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in serum linear perfluorooctane sulfonic acid (n-PFOS) (time frame: Baseline (Day 0) to Day 84 of each intervention period). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07846371, which also lists 1 linked publication.
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 8 Oct 2026; AzTrials last refreshed its copy on 26 Oct 2026.