Supplement
Flavanols are plant compounds in cocoa, tea, and apples that help blood vessels relax by raising nitric oxide. People mostly look at them for heart health, and a large trial of over 21,000 people found cocoa flavanols reduced cardiovascular deaths, while other work found better blood vessel function. Still, the evidence is limited: the death finding rests on one trial, and the blood pressure work was mostly lab-based.
Sources: PMID 11813978; PMID 23885956
- Updated
- How we grade
- 6 studies cited
- Best evidence
- Grade C
- Conditions studied
- 4
- Outcomes
- 5
- Graded outcomes
- 0032
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Endothelial Function Flavanols increase nitric oxide bioavailability and improve flow-mediated dilation, a validated marker of endothelial function. EFSA approved the health claim that 200mg cocoa flavanols daily helps maintain endothelium-dependent vasodilation. Bioavailability studies confirm gastrointestinal absorption of flavan-3-ols relevant to in vivo vascular effects. | Improves (the measure goes up) | Moderate effect | 2 studies | |||
Studies that measured endothelial function | ||||||
| Blood Pressure An in vitro study demonstrated dose-dependent inhibition of angiotensin converting enzyme (ACE) by flavan-3-ols and procyanidins, providing a mechanistic basis for blood pressure reduction. The EFSA-approved vascular elasticity claim and documented nitric oxide pathway activation support clinical relevance of this effect. | Improves (the measure goes down) | Small effect | 1 study | |||
Studies that measured blood pressure | ||||||
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Cardiovascular Mortality The COSMOS trial (n=21,442), a large RCT, found cocoa flavanol supplementation reduced cardiovascular mortality. EFSA has approved a health claim that 200mg cocoa flavanols daily helps maintain normal blood vessel elasticity, indicating regulatory-level recognition of cardiovascular benefit. | Improves (the measure goes down) | Moderate effect | 1 study | 21,442 people | ||
Studies that measured cardiovascular mortality | ||||||
Atherosclerosis
- LDL Oxidation: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| LDL Oxidation In vitro studies show flavan-3-ols and procyanidins protect liposomes against lipid oxidation and bilayer disruption. Cocoa procyanidins protect LDL from oxidation regardless of polymer chain length when monomer units are controlled, suggesting monomeric flavanols are the active species. | Improves (the measure goes down) | Moderate effect | 2 studies | |||
Antioxidant Status
- Antioxidant Status: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Antioxidant Status In vitro studies demonstrate cocoa flavanols and procyanidins protect human erythrocytes against free radical-induced hemolysis and protect liposomes from lipid peroxidation. Phenolic-rich cocoa powder with high flavanol content shows improved antioxidant capacity in food matrices. No controlled human antioxidant status trials are in the provided evidence set. | Improves (the measure goes up) | Small effect | 2 studies | |||
Key findings
- Endothelial FunctionImproves (the measure goes up)
- Cardiovascular MortalityImproves (the measure goes down)
- Blood PressureImproves (the measure goes down)
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- Grade C
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Studies cited
6 studies from PubMed
- Improvement of the Flavanol Profile and the Antioxidant Capacity of Chocolate Using a Phenolic Rich Cocoa Powder.
- Transepithelial permeability studies of flavan-3-ol-C-glucosides and procyanidin dimers and trimers across the Caco-2 cell monolayer.
- Inhibition of angiotensin converting enzyme (ACE) activity by flavan-3-ols and procyanidins.
- Flavan-3-ols and procyanidins protect liposomes against lipid oxidation and disruption of the bilayer structure.
- Cocoa procyanidin chain length does not determine ability to protect LDL from oxidation when monomer units are controlled.
- Bioavailability of flavan-3-ols and procyanidins: gastrointestinal tract influences and their relevance to bioactive forms in vivo.