Quercetin is one of the most studied dietary flavonoids and is often found in a variety of plant foods including fruits, vegetables, and tea. Although a lot of foods contain quercetin, the daily intake of quercetin for a person following a typical Western diet is estimated to be between 0 and 30 mg per day. However, research shows that the immune and cardiovascular benefits of quercetin are reached at supplemental intakes of 500 mg to 1,000 mg per day.
Quercetin plays multiple roles in supporting cardiovascular health. It helps maintain healthy blood pressure levels already in the normal range and helps promote the expression and activity of paraoxonase (PON), a HDL-associated protein with antioxidant properties. Quercetin also encourages healthy endothelial function.
Quercetin supports a healthy immune response. Preclinical studies demonstrate that quercetin affects immunity by acting on leukocytes and other immune cells.
Free radical scavenging antioxidants like quercetin protect cells from harmful free radicals and inhibit oxidative stress.