StrokeCALGUTNCT07173062
Algae Effects in Markers of Cardiovascular Risk and Gut Microbiome
A study testing Spirulina Arthrospira platensis (microalgae) and Gelidium corneum in people with Stroke and Coronary Arterial Disease (CAD), run by Universidade do Porto at 1 site in Portugal.
Trial summary
The Western diet, rich in fat and sugar, contributes to cardiovascular risk and alters the body metabolism, specifically through the modulation of the microbiome. Microbiome is considered the "second genome", functioning as an endocrine-like organ. Read more about this study
- Who is it for?
- Ages 50 years and older
- Conditions the study is for
- Stroke, Coronary Arterial Disease (CAD), Myocardial Infarction (MI)
- What is being tested?
- Spirulina Arthrospira platensis (microalgae) and Gelidium corneum
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 150 participants
- Where
- 1 sitePortugal
- Study dates
- 11 Mar 2025to Aug 2026
- 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 50 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- ≥50 years
- BMI ≥20 kg/m2
- History of stroke, coronary artery disease, myocardial infarction, peripheral artery disease, chronic kidney disease (eGFR <75 ml/min at least for 3 months), albuminuria >300 mg/g, or diabetes mellitus
- No antibiotics in the previous 30 days
- If a woman, she must be a woman of non-childbearing potential. That is, she must be:
- Surgically sterilized (e.g. underwent hysterectomy, bilateral salpingectomy or bilateral oophorectomy);
Show all 16Show fewer
- Clinically diagnosed infertile;
- In a post-menopausal state, defined as no menses for 12 months without an alternative medical cause.
- A woman patient of childbearing potential must have a negative serum pregnancy test at Visit 0 (Day 0) and must agree to use consistently and correctly (from 28 days prior to first study treatment administration until at least 7 days after last study treatment administration) one of the following highly effective methods of contraception:
- Abstinence of heterosexual intercourse (when this is in line with preferred and usual lifestyle of the subject);
- Progestogen-only hormonal contraception associated with inhibition of ovulation (oral, injectable, implantable);
- Combined (oestrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation (oral, intravaginal, transdermal);
- Intrauterine device;
- Intrauterine hormone-releasing system;
- Bilateral tubal occlusion;
- Vasectomized partner, who has received medical assessment of the surgical success, or clinically diagnosed infertile partner.
Who cannot join
- Unwilling to sign the informed consent form (if the patient wants to participate but cannot sign for any reason, then a third-person testimony may sign/complete the informed consent form on the patient's behalf).
- Involvement in the planning and/or conduct of the study (applies to both Investigator staff and/or staff at the study site).
- Participation in another clinical study with an investigational product during the last month.
- In participants recruited at Unidade Local de Saúde de São João, the exclusion criteria applied is estimated Glomerular Filtration Rate (eGFR) <30 ml/min/1.73m2 estimated with the CKD-EPI (2021) formula or dialysis. For participants recruited at community, this exclusion criteria is adapted for diagnosis of end-stage renal disease or dialysis (no need to quantify the eGFR).
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Portugal1 site, 1 recruiting
- Recruiting
Unidade Local de Saúde de São João
Porto, 4200-319
Francisca Saraiva, PhD, 225512100 ext. +351, f.saraiva@med.up.pt
João Pedro Ferreira, MD, PhD
About this study
Official title: Algae Effects in Markers of Cardiovascular Risk and Gut Microbiome: a Placebo-controlled Randomized Double-blind Trial
The Western diet, rich in fat and sugar, contributes to cardiovascular risk and alters the body metabolism, specifically through the modulation of the microbiome. Microbiome is considered the "second genome", functioning as an endocrine-like organ. Gut microbiota-derived metabolites, namely trimethylamine- N-oxide and short-chain fatty acids have been associated with atherosclerosis, vascular and cardiac diseases. Regarding trimethylamine- N-oxide, its association with cardiovascular disease is positive and dose-dependent. In contrast, short-chain fatty acids have been positively associated with the improvement of cardiovascular health.
Algae probiotics can modulate gut microbiome, stimulating the growth of commensal micro-organisms with health benefits. Previous studies suggested that Spirulina Arthrospira platensis supplementation could improve blood lipid levels and lower blood pressure, revealing anti-inflammatory and antioxidant roles. Other probiotics that could be beneficial to gut microbiota are macroalgae or seaweed. Macroalgae are a rich source of components which may prompt bacterial diversity and abundance.
The present prospective, randomized, three-armed parallel trial aims to generate good-quality evidence about the potential health effects and impact of Spirulina Arthrospira platensis (microalgae) and Gelidium corneum (macroalgae) supplements in humans. These participants will undergo 3 clinical evaluations: 2 before the beginning of micro- and macro-algae supplementation and the last one after 20 weeks of supplementation. The evaluation includes a vascular, nutritional and physical activity assessment, as well as blood, urine, saliva and stool collection for quantification of plasma biomarkers, oral and gut microbiota analysis, respectively.
- Conditions
- Stroke, Coronary Arterial Disease (CAD), Myocardial Infarction (MI), Diabetes Mellitus, Peripheral Artery Disease (PAD), Chronic Kidney Disease(CKD)
- Being tested
- Spirulina Arthrospira platensis (microalgae), Gelidium corneum, Placebo
- Keywords
- Spirulina Arthrospira platensis, Gelidium corneum, Trimethylamine- N-oxide (TMAO), Short-Chain Fatty Acids (SCFA), Cardiovascular risk (CVR)
- Medical subject headings
- Stroke, Myocardial Infarction, Diabetes Mellitus, Peripheral Arterial Disease, Renal Insufficiency, Chronic, Albuminuria
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Spirulina Arthrospira platensis (microalgae)Dietary supplement
Spirulina Arthrospira platensis (4 x ~500mg), taken twice daily as 2 capsules in the morning + 2 capsules in the evening
Gelidium corneumDietary supplement
Gelidium corneum (4 x ~500mg), taken twice daily as 2 capsules in the morning + 2 capsules in the evening
PlaceboOther
Microcrystalline cellulose, silicon dioxide and dicalcium phosphate (4 x ~500mg), taken twice daily as 2 capsules in the morning + 2 capsules in the evening
| Study group | Role | What they receive |
|---|---|---|
| Spirulina Arthrospira platensis | Experimental | during 20 weeks Receives: Dietary Supplement: Spirulina Arthrospira platensis (microalgae) |
| Gelidium corneum | Experimental | during 20 weeks Receives: Dietary Supplement: Gelidium corneum |
| Placebo | Placebo comparator | during 20 weeks Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Plasma trimethylamine-N-oxide levels
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the between-group ratio of geometric means difference of the Log transformed plasma trimethylamine- N-oxide levels change from baseline to 20 weeks.
The co-primary comparison will be Spirulina Arthrospira platensis versus Placebo and Gelidium corneum versus Placebo with a 2.5% alfa for each comparison.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Secondary outcomes (28)
Plasma short-chain fatty acids levels
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Gut microbiota
To assess the effect of the Spirulina Arthospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Systolic blood pressure
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Diastolic blood pressure
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Body weight
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Total cholesterol
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Low-density lipoprotein cholesterol
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
High-density lipoprotein cholesterol
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Lipoprotein A
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Triglycerides
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Interleukin-6
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Glucose
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Insulin
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Haemoglobin A1c
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Estimated Glomerular Filtration Rate
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Sodium
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Potassium
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
High-sensitivity C-reactive protein
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Oral microbiota
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the oral microbiota relative to the baseline.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Pulse wave velocity
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on arterial stiffness.
Measured by carotid-femoral pulse wave velocity using pulse wave analysis to assess arterial stiffness. Expressed in m/s. Higher values = greater arterial stiffness.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Intima-media thickness
To assess the effect of Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on vascular structure, measured by carotid intima-media thickness using cervical echo-Doppler ultrasound.
Measured by cervical echo-Doppler ultrasound in the common carotid artery (automatic recording of 5 cycles). Expressed in mm. Lower values = better vascular structure.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Cerebral blood flow velocities
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on cerebral blood flow.
Measured by transcranial color-coded duplex Doppler in middle cerebral arteries and posterior cerebral arteries. Expressed in cm/s. Higher values = greater blood flow velocity.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Cerebral blood flow resistance indexes
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on cerebral vascular resistance.
Measured by transcranial color-coded duplex Doppler in middle cerebral arteries and posterior cerebral arteries. Expressed as resistance index (RI), calculated from Doppler waveforms. Higher RI = greater vascular resistance.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Cerebral vascular reactivity
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on cerebral vascular reactivity.
Measured by transcranial color-coded duplex Doppler during a breathing manoeuvre. Expressed as % change in blood flow velocity in middle cerebral arteries and posterior cerebral arteries, in response to hypercapnia. Greater reactivity = better cerebrovascular function.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Breath-holding index
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on cerebrovascular reserve capacity.
Measured by transcranial color-coded duplex Doppler in middle cerebral arteries and posterior cerebral arteries during a 20-second apnea manoeuvre. Expressed as index value. Higher BHI = better vascular reserve.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Neurovascular coupling (visual stimulation)
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on neurovascular coupling.
Measured by transcranial color-coded duplex Doppler during visual stimulation with a flickering checkerboard (10 Hz). Expressed as blood velocity change in middle cerebral arteries and posterior cerebral arteries recorded across cycles of 20 seconds stimulation (eyes open) and 20 seconds rest (eyes closed). Greater change = better neurovascular coupling.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Mediterranean diet adherence screener score
To assess the effect of Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change in adherence to the Mediterranean diet, as measured by the Mediterranean Diet Adherence Screener (MEDAS).
The MEDAS is a 14-item questionnaire that evaluates food intake habits and frequency of consumption of specific foods. Each item receives 1 point for a positive response, resulting in a total score ranging from 0 to 14. Higher scores indicate greater adherence to the Mediterranean diet, with a score of ≥10 considered adherent.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Total score of physical activity
To assess the effect of Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change in total physical activity score, as measured by the International Physical Activity Questionnaire - short version.
This questionnaire includes 7 items assessing frequency and duration of physical activity during the past 7 days across different domains. Activities are weighted by metabolic equivalents (METs) (walking = 3, moderate = 4, vigorous = 8), and a total score is expressed as MET-minutes/week. Scores range from 0 to several thousand, with higher values indicating greater physical activity.
Measured: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Sep 2025
- Study start11 Mar 2025
- Primary completionAug 2026 (estimated)
- Study completionAug 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for StrokeStudies 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
- Model description
- Prospective, randomized, double-blind, two-treatment, one-period, parallel trial
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 150 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universidade do Porto
- Sponsor type
- University, hospital or other
- Collaborators
- Centro Hospitalar De São João, E.P.E.
- Responsible party
- Sponsor
- Investigators
- João Pedro Ferreira, MD, PhD, Principal investigator, Universidade do Porto
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07173062
- Sponsor's protocol ID
- CALGUT
- Acronym
- CALGUT
- Status last verified
- Sep 2025
- First submitted
- 12 Aug 2025
- Last updated
- 15 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 15 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Algae Effects in Markers of Cardiovascular Risk and Gut Microbiome: a Placebo-controlled Randomized Double-blind Trial
- ClinicalTrials.gov ID
- NCT07173062
- Acronym / sponsor ID
- CALGUT / CALGUT
- Conditions
- Stroke, Coronary Arterial Disease (CAD), Myocardial Infarction (MI), Diabetes Mellitus, Peripheral Artery Disease (PAD), Chronic Kidney Disease(CKD)
- Keywords
- Spirulina Arthrospira platensis, Gelidium corneum, Trimethylamine- N-oxide (TMAO), Short-Chain Fatty Acids (SCFA), Cardiovascular risk (CVR)
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 150 participants (estimated)
- Lead sponsor
- Universidade do PortoUniversity, hospital or other
- Collaborators
- Centro Hospitalar De São João, E.P.E.
- Study start
- 11 Mar 2025 (actual)
- Primary completion
- Aug 2026 (estimated)
- Study completion
- Aug 2026 (estimated)
- First posted
- 15 Sep 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 Western diet, rich in fat and sugar, contributes to cardiovascular risk and alters the body metabolism, specifically through the modulation of the microbiome. Microbiome is considered the "second genome", functioning as an endocrine-like organ. Gut microbiota-derived metabolites, namely trimethylamine- N-oxide and short-chain fatty acids have been associated with atherosclerosis, vascular and cardiac diseases. Regarding trimethylamine- N-oxide, its association with cardiovascular disease is positive and dose-dependent. In contrast, short-chain fatty acids have been positively associated with the improvement of cardiovascular health.
Algae probiotics can modulate gut microbiome, stimulating the growth of commensal micro-organisms with health benefits. Previous studies suggested that Spirulina Arthrospira platensis supplementation could improve blood lipid levels and lower blood pressure, revealing anti-inflammatory and antioxidant roles. Other probiotics that could be beneficial to gut microbiota are macroalgae or seaweed. Macroalgae are a rich source of components which may prompt bacterial diversity and abundance.
The present prospective, randomized, three-armed parallel trial aims to generate good-quality evidence about the potential health effects and impact of Spirulina Arthrospira platensis (microalgae) and Gelidium corneum (macroalgae) supplements in humans. These participants will undergo 3 clinical evaluations: 2 before the beginning of micro- and macro-algae supplementation and the last one after 20 weeks of supplementation. The evaluation includes a vascular, nutritional and physical activity assessment, as well as blood, urine, saliva and stool collection for quantification of plasma biomarkers, oral and gut microbiota analysis, respectively.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
- Model description
- Prospective, randomized, double-blind, two-treatment, one-period, parallel trial
| Arm | Type | Receives |
|---|---|---|
| Spirulina Arthrospira platensis | Experimental | Dietary Supplement: Spirulina Arthrospira platensis (microalgae)during 20 weeks |
| Gelidium corneum | Experimental | Dietary Supplement: Gelidium corneumduring 20 weeks |
| Placebo | Placebo comparator | Other: Placeboduring 20 weeks |
Who may qualify
- Ages
- 50 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (16 listed)
- ≥50 years
- BMI ≥20 kg/m2
- History of stroke, coronary artery disease, myocardial infarction, peripheral artery disease, chronic kidney disease (eGFR <75 ml/min at least for 3 months), albuminuria >300 mg/g, or diabetes mellitus
- No antibiotics in the previous 30 days
- If a woman, she must be a woman of non-childbearing potential. That is, she must be:
Key exclusion criteria (4 listed)
- Unwilling to sign the informed consent form (if the patient wants to participate but cannot sign for any reason, then a third-person testimony may sign/complete the informed consent form on the patient's behalf).
- Involvement in the planning and/or conduct of the study (applies to both Investigator staff and/or staff at the study site).
- Participation in another clinical study with an investigational product during the last month.
- In participants recruited at Unidade Local de Saúde de São João, the exclusion criteria applied is estimated Glomerular Filtration Rate (eGFR) <30 ml/min/1.73m2 estimated with the CKD-EPI (2021) formula or dialysis. For participants recruited at community, this exclusion criteria is adapted for diagnosis of end-stage renal disease or dialysis (no need to quantify the eGFR).
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 |
|---|---|---|
| Spirulina Arthrospira platensis (microalgae)Spirulina Arthrospira platensis (4 x ~500mg), taken twice daily as 2 capsules in the morning + 2 capsules in the evening | Dietary supplement | Spirulina Arthrospira platensis |
| Gelidium corneumGelidium corneum (4 x ~500mg), taken twice daily as 2 capsules in the morning + 2 capsules in the evening | Dietary supplement | Gelidium corneum |
| PlaceboMicrocrystalline cellulose, silicon dioxide and dicalcium phosphate (4 x ~500mg), taken twice daily as 2 capsules in the morning + 2 capsules in the evening | Other | Placebo |
Primary outcome
Plasma trimethylamine-N-oxide levels
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the between-group ratio of geometric means difference of the Log transformed plasma trimethylamine- N-oxide levels change from baseline to 20 weeks. The co-primary comparison will be Spirulina Arthrospira platensis versus Placebo and Gelidium corneum versus Placebo with a 2.5% alfa for each comparison.
28 secondary outcomes
Plasma short-chain fatty acids levels
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Gut microbiota
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Systolic blood pressure
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Diastolic blood pressure
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Body weight
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Total cholesterol
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Low-density lipoprotein cholesterol
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
High-density lipoprotein cholesterol
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Lipoprotein A
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Triglycerides
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Interleukin-6
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Glucose
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Insulin
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Haemoglobin A1c
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Estimated Glomerular Filtration Rate
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Sodium
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Potassium
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
High-sensitivity C-reactive protein
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Oral microbiota
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Pulse wave velocity
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Intima-media thickness
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Cerebral blood flow velocities
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Cerebral blood flow resistance indexes
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Cerebral vascular reactivity
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Breath-holding index
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Neurovascular coupling (visual stimulation)
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Mediterranean diet adherence screener score
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Total score of physical activity
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
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 15 Sep 2025.
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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.
João Pedro Ferreira, MD, PhD principal investigator
Universidade do Porto
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Spirulina Arthrospira platensis (microalgae) and Gelidium corneum in people with Stroke and Coronary Arterial Disease (CAD), run by Universidade do Porto 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 16 inclusion and 4 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 15 Sep 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 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?
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 Francisca Saraiva, PhD (220426820 ext. +351, f.saraiva@med.up.pt), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Plasma trimethylamine-N-oxide levels (time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)). 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 15 Sep 2025; AzTrials last refreshed its copy on 26 Oct 2026.