Quercetin is a phytochemical that is part of the colouring found in the skins of apples and red onions. It is the most abundant of the flavenoids, and is also a building block for other flavenoids. It is a powerful antioxidant, as well as being a natural antihistamine and anti-inflammatory. About 70 percent of the total flavenoid intake from food comes from quercetin.
Quercetin can improve cardiovascular health, and reduce cancer risk. It helps to combat free radicals which cause damage to cells in the body. Like many other flavenoids, quercetin prevents the oxidation of LDL or bad cholesterol. The anti-inflammatory effect of quercetin is due to its ability to inhibit enzymes such as lipoxygenase, and the ability to inhibit inflammatory mediators.
Quercetin also inhibits the release of histamine, which causes congestion, by basophils and mast cells. This means that it can be helpful for allergies, hay fever, and asthma. Quercetin also increases the effectiveness and activity of vitamin C in the body, and inhibits the inflammatory processes involved in sinusitis. A quercetin deficiency can also lead to varicose veins.
Quercetin can be found in the following foods:
Note that quercetin works best with bioflavonoids, vitamin B6, vitamin C, vitamin E, zinc, and tyrosine.
Quercetin Supplements Quercetin supplements are available in capsule or softgel forms. Store the supplements in a cool, dry place away from direct heat and always check dosage levels and product level instructions before use. Always talk to a medical professional before beginning quercetin supplementation.