Flavanols

Flavanols are a subclass of flavonoids found abundantly in cocoa, tea, apples, grapes, and berries. Includes catechins, epicatechins, and their polymers (procyanidins). NO GRADED OUTCOMES in this entry - see cocoa and green tea for specific evidence. The COSMOS trial (21,442 participants) found cocoa flavanols reduced cardiovascular mortality. EFSA approved health claim: 200mg cocoa flavanols daily helps maintain normal blood vessel elasticity. Mechanism: increase nitric oxide, improve endothelial function, lower blood pressure. Important distinction: flavanols (with an 'a') are different from flavonols (quercetin, kaempferol).

Quick Answer

What it is

Flavanols are a subclass of flavonoids found abundantly in cocoa, tea, apples, grapes, and berries. Includes catechins, epicatechins, and their polymers (procyanidins).

Key findings

Grade C: Endothelial Function
Grade C: Blood Pressure
Grade C: Cardiovascular Mortality

Safety

No specific caution or interaction language was detected in the current summary/outcome notes.

ℹ️ Quick Facts: Flavanols

Quick Facts: Flavanols

Best Evidence:Grade C
Conditions Studied:4
Research Outcomes:5
Key Effect:Cardiovascular Health

Outcomes by grade:

4 conditions · 5 outcomes

Detailed Outcomes

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.

moderate↑Improves

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.

small↓Improves

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.

21442 participants

moderate↓Improves

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.

small↑Improves

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.

moderate↓Improves

Evidence by Condition

Best grade per condition (each condition may have multiple outcomes)

CCardiovascular Health

2 outcomes · 4 studies

↑Endothelial FunctionImproves↓Blood PressureImproves

CCardiovascular Disease

1 outcome · 1 study

↓Cardiovascular MortalityImproves

DAntioxidant Status

1 outcome · 3 studies

↑Antioxidant StatusImproves

DAtherosclerosis

1 outcome · 2 studies

↓LDL OxidationImproves

Research Citations (6)

Improvement of the Flavanol Profile and the Antioxidant Capacity of Chocolate Using a Phenolic Rich Cocoa Powder.

Foods (Basel, Switzerland) (2020)

PMID: 32074967

Transepithelial permeability studies of flavan-3-ol-C-glucosides and procyanidin dimers and trimers across the Caco-2 cell monolayer.

Journal of Agricultural and Food Chemistry (2013)

PMID: 23885956

Inhibition of angiotensin converting enzyme (ACE) activity by flavan-3-ols and procyanidins.

FEBS Letters (2003)

PMID: 14675780

Flavan-3-ols and procyanidins protect liposomes against lipid oxidation and disruption of the bilayer structure.

Free Radical Biology & Medicine (2003)

PMID: 12498983

Cocoa procyanidin chain length does not determine ability to protect LDL from oxidation when monomer units are controlled.

The Journal of Nutritional Biochemistry (2002)

PMID: 12550061

Bioavailability of flavan-3-ols and procyanidins: gastrointestinal tract influences and their relevance to bioactive forms in vivo.

Antioxidants & Redox Signaling (2001)

PMID: 11813978

Related Supplements

Danshen

3 shared conditions · 9 outcomes

Danshen (Salvia miltiorrhiza) is one of the most widely used Traditional Chinese Medicine herbs for cardiovascular health. Contains tanshinones and salvianolic acids with demonstrated anticoagulant, antioxidant, and vasodilatory effects. The largest herbal medicine market in China. Compound Danshen Dripping Pills are used for angina. Human evidence exists but many studies are of lower quality. Important: Strong interaction with warfarin and other blood thinners.

Cyanidin

3 shared conditions · 10 outcomes

Cyanidin is a type of anthocyanin pigment found in dark berries, purple vegetables, and black rice. Cyanidin-3-glucoside (C3G) is the most studied form. Shows promise for blood glucose regulation, anti-inflammatory effects, and metabolic health. Notable for potentially improving glucose uptake without impairing muscle protein synthesis (unlike some AMPK activators). However, bioavailability is a major concern - most cyanidin is rapidly metabolized. Human evidence is limited despite promising in vitro data.

Chinese Hawthorn

3 shared conditions · 5 outcomes

Chinese hawthorn (Crataegus pinnatifida) differs from European hawthorn (C. oxyacantha) primarily in use pattern - Chinese hawthorn is used more for digestion and lipids, European for cardiovascular. The berries are eaten as food and used in Traditional Chinese Medicine for 'food stagnation' (digestive aid). Contains flavonoids, triterpenes, and organic acids. Limited human research shows potential for lipid lowering and digestive benefits. Some anti-inflammatory and anti-allergy effects in preclinical studies.

Vitamin C

2 shared conditions · 262 outcomes

Vitamin C, or ascorbic acid, is an essential vitamin and a very popular supplement due to its antioxidant properties, safety profile, and low price. Many people supplement with vitamin C because it is believed to reduce symptoms of the common cold.

Niacin (Vitamin B3)

2 shared conditions · 117 outcomes

Niacin is a form of vitamin B3. Supplementation with niacin (nicotinic acid) can improve cholesterol levels; however, niacin's inability to reduce cardiovascular disease risk and its association with adverse effects make its use controversial.

Terminalia Chebula

2 shared conditions · 12 outcomes

Terminalia chebula (Haritaki) is one of the three fruits in Triphala, an important Ayurvedic formula. Considered 'king of medicines' in Tibet. Contains tannins and antioxidants. Traditional uses include digestive issues, oral health, and as a general 'rejuvenative.' NO GRADED OUTCOMES - human research is very limited. Preclinical research shows antimicrobial, antioxidant, and anti-diabetic potential. Primarily available as part of Triphala rather than alone.

Squalene

2 shared conditions · 4 outcomes

Squalene is a triterpene found in olive oil, shark liver oil, and produced endogenously in humans as a cholesterol precursor. Some research suggests benefits for cholesterol and immune function. NO GRADED OUTCOMES. The 'sharks don't get cancer' myth was debunked (sharks do get cancer), but squalene may have modest health benefits. Available from plant sources (olive, amaranth) for those avoiding shark products. Used as vaccine adjuvant (MF59). Generally safe.

Society garlic

2 shared conditions · 6 outcomes

Society garlic is a South African plant (not true garlic) traditionally used for infections and as food flavoring. Contains sulfur compounds similar to garlic. Limited research suggests possible cardiovascular and antimicrobial effects. Some animal studies show testosterone effects, but evidence is preliminary. NO GRADED OUTCOMES. Not widely available as a supplement. Safer than true garlic with milder taste (hence 'society' - can be eaten before social events).