Algae Effects in Markers of Cardiovascular Risk and Gut Microbiome

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.

Inclusion Criteria:

• ≥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);
  • 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.

Exclusion Criteria:

• 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).