Quercetin is a plant pigment (flavonoid). It is found in many plants and foods, such as red wine, onions, green tea, apples, berries, Ginkgo biloba, St. John’s wort, and others. Buckwheat tea has a large amount of quercetin. People use quercetin as a medicine.
Quercetin is used for treating conditions of the heart and blood vessels including “hardening of the arteries” (atherosclerosis), high cholesterol, high blood pressure, heart disease, and circulation problems. It is also used for diabetes, cataracts, hay fever, peptic ulcer, schizophrenia, inflammation, asthma, gout, viral infections, chronic fatigue syndrome (CFS), preventing cancer, for treating chronic infections of the prostate, improving the function of kidney transplants, and increasing exercise endurance.
Benefits of Quercetin
Here’s a look at the science behind quercetin health’s effects.
Quercetin is thought to prevent the release of histamine from certain immune cells. (An inflammatory chemical, histamine is involved in allergic symptoms such as sneezing and itching.)
Although lab experiments suggest that quercetin may help fight allergies, a 2002 report cautions that “there are no good clinical research data on the use of quercetin” for patients with allergic rhinitis.
High Blood Pressure
In a 2007 study of 41 adults, researchers found that taking 730 mg of quercetin daily for 28 days reduced blood pressure in people with hypertension. However, blood pressure was not altered in study members with prehypertension (a condition marked by slightly elevated blood pressure).
Quercetin may be no better than a placebo when it comes to enhancing athletic performance, according to a 2009 study of 30 healthy men. For the study, some participants consumed a sports drink containing 250 mg of quercetin four times a day for up to 16 days, while a placebo group drank the same beverage without quercetin. Results showed that the short-term quercetin supplementation failed to improve cycling performance and the ability of muscles to synthesise energy.
Chronic Pelvic Pain Syndrome
Findings from a randomised, double-blind, placebo-controlled trial indicate that use of quercetin supplements may improve symptoms in most men with chronic pelvic pain syndrome. The study involved 30 men with prostatitis, a condition that involves inflammation of the prostate gland.
Quercetin and Cancer
Studies on cell cultures have shown that quercetin may help slow the growth of some types of cancer cells. What’s more, some animal-based research indicates that quercetin may protect against certain types of cancer (such as colon cancer). However, since there is currently a lack of human studies on quercetin’s cancer-fighting effects, it’s too soon to tell whether quercetin might play a significant role in cancer prevention.
For now, the American Cancer Society states that it is “reasonable to include foods that contain quercetin as part of a balanced diet with an emphasis on fruits, vegetables, legumes, and whole grains.”
Quercetin and Bromelain
When taking quercetin in supplement form, it may be beneficial to choose a product that also contains papain and/or bromelain (plant-derived enzymes shown to increase the intestine’s absorption of quercetin).