flavanoleihin

Flavanols are a subgroup of flavonoids, specifically flavan-3-ols, found in a wide range of plant foods and beverages. The most studied monomeric units are catechin and epicatechin, and these can polymerize to form proanthocyanidins (also called condensed tannins). Flavanols vary in their hydroxylation pattern and degree of polymerization, which influence their bioavailability and biological activity.

Dietary sources are diverse. Cocoa and dark chocolate are particularly rich in flavanols, as are tea (especially green tea), grapes and grape products, apples, berries, and some nuts and legumes. The content of flavanols in foods is affected by plant variety, ripeness, processing, and preparation. After ingestion, monomeric catechins and epicatechins are absorbed in the small intestine and undergo rapid metabolism to various conjugates. Larger proanthocyanidins have limited intestinal absorption and are largely degraded by gut microbiota into smaller phenolic metabolites before systemic absorption.

Evidence on health effects is mixed but generally suggests potential cardiovascular benefits. Observational studies associate higher flavanol intake with lower risk of cardiovascular disease, while randomized trials report modest improvements in endothelial function, blood pressure, and some lipid markers, with inconsistent findings across populations and outcomes. Research on cognitive function and cancer risk remains inconclusive. Safety profiles are favorable at typical dietary intakes; very high intakes may cause gastrointestinal discomfort and can affect mineral absorption in sensitive individuals. Processing can reduce flavanol content, as seen in dutched (alkalized) cocoa and some commercial teas.

See also: polyphenols, catechins, proanthocyanidins.