Quercetin Information and Facts

Quercetin belongs to a group of water-soluble pigments known as flavonoids. Quercetin is a member of the class of flavonoids called flavonols. It is widely distributed in the plant kingdom in rinds and barks and can be found in onions, red wine, green tea and st. john's wort.

Potential benefits of quercetin include:
  • Quercentin is an antioxidant, and thus may help fight cell-damaging free radicals.

  • Population studies have found that people with high intakes of foods containing quercetin and other flavonoids tend to have better cardovascular health.

  • Several studies have linked a high intake of apples (rich in quercetin and other flavonoids) with improved lung function and a lower risk of certain respiratory diseases.

  • Quercetin blocks an enzyme that leads to accumulation of sorbitol which has been linked to nerve, eye, and kidney damage in those with diabetes. However, no human research has demonstrated these actions of quercetin in people with diabetes patients.

The benefits of quercetin have not yet been confirmed by human pharmacological studies.

Dosage and Administration

Some doctors recommend 200-500 mg of quercetin taken two to three times per day. However, no optimal or recommended dosage is known.

xyz