Black Forest Cocoa Flavanol Supplementation and Health Trial

Overview

This randomized, double-blind, controlled clinical trial will evaluate the effects of daily cocoa flavanol supplementation on vascular and inflammatory biomarkers in healthy adult men aged 30 to 75 years. Participants will be randomized to receive either a cocoa flavanol supplement or a nutrient-matched low-flavanol control product for 4 to 8 weeks. The study will assess changes in inflammatory biomarkers, endothelial function, oxidative stress markers, vascular measurements, and circulating endothelial progenitor cell-related markers. Optional assessments include flow-mediated dilation and single-cell RNA sequencing of peripheral blood mononuclear cells to explore mechanistic biological responses to cocoa flavanol supplementation.

Detailed description

This is an early-phase, randomized, double-blind, controlled mechanistic clinical trial designed to evaluate the effects of daily cocoa flavanol supplementation on vascular biology and inflammatory biomarkers in healthy adults.

Participants aged 30 to 75 years will be randomized in a 1:1 ratio to receive either:

A cocoa flavanol supplement providing approximately 1,200 mg total flavanols daily, or A nutrient-matched low-flavanol cocoa-based control product.

The intervention period will last 4 to 8 weeks. Study products will be provided in identical packaging to maintain blinding.

Primary objectives include evaluating changes in biomarkers associated with endothelial function and systemic inflammation, including hs-CRP, IL-6, IL-1β, IL-10, VCAM-1, ICAM-1, E-selectin, TNF-α, CCL2, CCL4, and IFN-γ.

Secondary objectives include assessment of oxidative stress and vascular tone markers, blood pressure, pulse wave velocity, endothelial progenitor cell-related markers, endothelial microparticles, and nitric oxide-related biomarkers. Optional mechanistic assessments include flow-mediated dilation and single-cell RNA sequencing analyses in a participant subset.

Blood samples and vascular measurements will be obtained at baseline and at the end of the intervention period. The study is designed to explore physiologic and biomarker responses associated with cocoa flavanol supplementation in a healthy adult population

Interventions

• Dietary supplement Cocoa Flavanol Supplement
  A powdered cocoa flavanol dietary supplement administered orally once daily for 4 to 8 weeks. Each daily serving contains approximately 1,200 mg total cocoa flavanols in a 10 g powder formulation. The supplement is mixed with water or a non-alcoholic beverage and consumed in a blinded fashion.
• Dietary supplement Low-Flavanol Control Powder
  A nutrient-matched low-flavanol cocoa-based powder administered orally once daily for 4 to 8 weeks. The control product contains less than 2% total flavanols and is designed to match the active supplement in appearance, taste, and administration while minimizing biologically active flavanol exposure.

Primary outcome measures

• Change From Baseline in Circulating C-Reactive Protein Concentration [Time frame: Baseline and Week 4]
• Change From Baseline in Circulating Interleukin-6 Concentration [Time frame: Baseline and Week 4]
• Change From Baseline in Circulating Vascular Endothelial Growth Factor A Concentration [Time frame: Baseline and Week 4]
• Change From Baseline in Circulating Endothelin-1 Concentration [Time frame: Baseline and Week 4]
• Change From Baseline in Circulating Stromal Cell-Derived Factor 1 Alpha Concentration [Time frame: Baseline and Week 4]
• Change From Baseline in Circulating E-Selectin Concentration [Time frame: Baseline and Week 4]
• Change From Baseline in Circulating Intercellular Adhesion Molecule-1 Concentration [Time frame: Baseline and Week 4]
• Change From Baseline in Circulating Vascular Cell Adhesion Molecule-1 Concentration [Time frame: Baseline and Week 4]
• Change From Baseline in Circulating C-C Motif Chemokine Ligand 4 Concentration [Time frame: Baseline and Week 4]
• Change From Baseline in Circulating C-C Motif Chemokine Ligand 2 Concentration [Time frame: Baseline and Week 4]

Secondary outcome measures (2)

• Change From Baseline in Circulating Endothelial Progenitor Cell Frequency [Time frame: Baseline and 4 weeks after the first dose]
• Change From Baseline in Circulating Nitric Oxide Metabolite Concentration [Time frame: Baseline and Week 4]

Eligibility criteria

Inclusion criteria

• Male participants aged 30 to 75 years.
• Able and willing to provide written informed consent.
• Generally healthy, as determined by medical history and screening assessments.
• Willing and able to comply with all study procedures, including blood collection, daily study-product intake, and required study visits.
• Willing to consume the assigned cocoa flavanol supplement or low-flavanol control product once daily for the duration of the study.
• Willing to provide peripheral blood samples at baseline and at the end of the intervention.
• Willing to maintain generally stable dietary, exercise, sleep, medication, and supplement habits during the study.
• Willing to refrain from initiating new supplements, restrictive diets, fasting regimens, or major exercise programs during the study.
• Not currently taking medications or supplements known to substantially affect vascular function, nitric oxide pathways, inflammation, oxidative stress, or coagulation, unless approved by the investigator.

Exclusion criteria

• Female biological sex.
• Younger than 30 years or older than 75 years.
• Known cardiovascular, metabolic, renal, hepatic, inflammatory, or autoimmune disease, including coronary artery disease, diabetes mellitus, chronic kidney disease, chronic liver disease, rheumatoid arthritis, or another clinically significant inflammatory disorder.
• Hypertension requiring prescription medication.
• Active infection, acute illness, or other clinically significant medical condition at screening or baseline.
• Current use of medications or supplements that may substantially affect vascular function, inflammatory biomarkers, nitric oxide pathways, oxidative stress, or coagulation, including chronic nonsteroidal anti-inflammatory drugs, systemic corticosteroids, anticoagulants, antiplatelet drugs, prescription immunomodulatory agents, phosphodiesterase-5 inhibitors, or high-dose antioxidant supplements, unless approved by the investigator.
• Known allergy, hypersensitivity, or intolerance to cocoa, chocolate, cocoa flavanols, or any ingredient in either study product.
• Gastrointestinal disease or condition that may interfere with digestion or absorption of the study product, including celiac disease, inflammatory bowel disease, active gastritis, or a clinically significant malabsorption disorder.
• Current smoking or vaping of nicotine or cannabis products.
• Major psychiatric illness, cognitive impairment, or another condition that may interfere with informed consent, adherence, or completion of study procedures.
• Alcohol or drug abuse within the previous 12 months that, in the investigator's judgment, may affect participant safety or study adherence.
• Participation in another interventional clinical study within 30 days before screening.
• Plans to begin a new medication, supplement, restrictive diet, fasting regimen, or major exercise program during the study period.
• Any condition or circumstance that, in the investigator's judgment, would increase participant risk, interfere with study procedures, compromise adherence, or affect interpretation of the study results.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Triple blind

Primary purpose

Basic science

Study locations

United States · 2 centers

• Black Forest Supplements (The Black Forest LLC) — Miami
• Power Wellness Spot — Miami

Identifiers

NCT: NCT07747714 · BF-CF-HEALTH-001 · Pro00092276

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗