Flavonoids, a diverse group of polyphenolic compounds found in many fruits, vegetables, and plant-based foods, have been investigated for their potential role in supporting cardiovascular health, including the prevention and management of arteriosclerosis (hardening and narrowing of the arteries). Scientific studies suggest that flavonoids may exert beneficial effects through several mechanisms relevant to arteriosclerosis, such as antioxidative activity, anti-inflammatory effects, improvement of endothelial function, and inhibition of platelet aggregation.

Epidemiological research has linked higher dietary intake of flavonoid-rich foods with reduced risk of cardiovascular diseases and improved vascular health. Meta-analyses of prospective cohort studies have reported inverse associations between flavonoid consumption and incidence of coronary heart disease and stroke. Laboratory and animal studies provide mechanistic support, showing that specific flavonoids (e.g., quercetin, catechins, anthocyanins) can reduce oxidative stress and inflammation in blood vessels, both of which are key contributors to arteriosclerosis.

However, most evidence pertains to flavonoid-rich diets or specific flavonoids rather than "unspecified flavonoids" as a supplement or therapy. Human clinical trials are often limited by heterogeneity in flavonoid types, dosages, and study designs, so while there is moderate scientific evidence supporting an association between flavonoid intake and reduced risk of arteriosclerosis, robust clinical trial data for supplementation remain limited.