Know Your Phytochemicals: Quercetin!

What is a phytochemical?
Phytochemicals are naturally-occurring chemical compounds found in plants that help to promote, support, and maintain good health. Phytochemicals are not vitamins or minerals, as they are generally not considered absolutely essential to life. However, a diet high in phytochemicals is correlated with better health outcomes. Phytochemicals are found in plant-based foods only; meat and animal products are not known to contain any phytochemicals at this point in time.


Quercetin (kah-where-set-in) falls into the phytochemical subcategory of bioflavonoids, a component of the color pigments seen in various plants. Quercetin is specifically found in: 

  • kale, 
  • broccoli, 
  • green tea, 
  • onions (particularly yellow and red), 
  • citrus fruits, 
  • apples, 
  • parsley, 
  • red wine, 
  • olive oil, 
  • ginkgo, 
  • grapes, 
  • sage, 
  • dark berries, and 
  • dark cherries. 

Quercetin may be best known for its anti-inflammatory properties, as it prevents the immune system from releasing specific cells, called mast cells, which function to promote inflammation and the release of histamines. While short-term inflammation is very useful in certain situations — like for healing a bruise or wound — chronic inflammation, as seen in many Americans, can be very damaging to health. Quercetin’s anti-histamine characteristics also help reduce allergic reactions, and may alleviate asthma symptoms, hives, and eczema.

Additionally, quercetin is a potent antioxidant, renowned for its anti-cancer capacities. It works to prevent DNA damage caused by environmental chemicals and toxins, and is reported to inhibit colon cancer as well as inflammatory lung diseases.

Recent research by the British Journal of Nutrition indicates that quercetin serves to lower blood pressure in overweight individuals with or at risk for high blood pressure. In this study, 70 patients were observed in a randomized double-blind study with a placebo control group. Those with high blood pressure experienced a significant decrease in their systolic blood pressure, which suggests that quercetin has properties that protect the heart and cardiovascular system. Quercetin is currently known for its relaxing effect on blood vessels, likely related to its ability to help prevent plaque from building up in the arteries (atherosclerosis). 

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