Health Benefits of Quercetin
Quercetin is a natural fat-soluble antioxidant. It is classified as a bioflavonoid, a type of plant pigment largely responsible for the vibrant colors of many fruits and vegetables. These bioflavonoids were once called vitamin P due to their presence in paprika and their vitamin-like properties. Indeed, quercetin works particularly well with vitamin C and other nutrients to promote good health.
Quercetin is known to be particularly abundant in apples and onions, but it is also found in other fruits, vegetables, herbs, and grains. However, as a fat-soluble nutrient, it can be difficult to absorb without the presence of dietary fats (see below).
Quercetin – an antioxidant that supports cardiovascular health
Like other bioflavonoids, quercetin exhibits strong antioxidant activity, thus helping to counteract oxidative stress and the negative effects of aging. Since this antioxidant activity also helps support cardiovascular health, quercetin is used in herbal medicine to protect small blood vessels called capillaries.
Quercetin is associated with various activities that can support arterial health, including:[1]
- It inhibits the oxidation of low-density lipoproteins (LDL cholesterol)
- It reduces levels of adhesion molecules and inflammatory markers
- It protects nitric oxide and endothelial function during oxidative stress
- It supports normal platelet activity
Together, these activities help blood vessels remain flexible and reactive, dilating and contracting as needed to maintain normal blood circulation.
Antiviral Activity of Quercetin
The antiviral potential of quercetin has been examined in numerous studies, and preliminary results suggest that this bioflavonoid could inhibit the ability of certain influenza viruses to enter cells, which would help prevent infection.[2] The possible antiviral effects of quercetin appear to be linked to its ability to help prevent a virus from replicating and causing infection, by inhibiting polymerases, proteases, and reverse transcriptase, blocking DNA gyrase, and binding to viral capsid proteins.[3]
Some data also indicate that vitamin C and quercetin have synergistic antiviral action due to their overlapping immunomodulatory properties and because vitamin C can "recycle" quercetin, which increases its effectiveness.5 In turn, quercetin and other bioflavonoids enhance the body's absorption of vitamin C and increase its effectiveness by delaying its elimination.[4] And, since quercetin is fat-soluble, it provides benefits to lipid membranes that water-soluble vitamin C cannot reach.
Quercetin for Allergy Management
Quercetin is also well-recognized for its ability to help manage allergy symptoms. When my dogwood allergy flares up, my first instinct is to take quercetin. If I remember, I start taking it a few weeks before the first dogwood blossoms appear so my body can prepare to block histamine release.
According to a 2016 review on quercetin:[5]
"Quercetin is known for its antioxidant activity (scavenging free radicals) as well as its anti-allergic properties characterized by immune system stimulation, antiviral activity, inhibition of histamine release [and] a decrease in pro-inflammatory cytokines."
Quercetin can also support the rest of the helper T cells and antigen-specific antibodies; it inhibits the production and release of histamine and appears to stabilize mast cell membranes (immune cells heavily involved in the occurrence of allergic reactions).[6] These immunomodulatory and anti-inflammatory actions contribute to quercetin's usefulness against allergic rhinitis, seasonal allergies, and other allergic reactions.[1,7]
Quercetin Absorption
The bad news is that quercetin in its raw form used in most supplements is poorly absorbed, largely because it is fat-soluble. This means its clinical efficacy is very limited unless it is offered in an absorbable form.
Enzymatically Modified Isoquercitrin (EMIQ) is a highly bioavailable soluble quercetin obtained through a natural enzymatic process that allows for superior bioavailability. Natural Factors' Bioactive Quercetin EMIQMD reaches optimal concentration in the blood in just 15 minutes, providing almost instant antioxidant support!
Natural Factors' Quercetin LipoMicel Matrix is another excellent choice, as this quercetin preparation provides an advanced form of this antioxidant that is 10 times more absorbable than ordinary forms. The unique, patent-pending LipoMicel technology helps overcome the problem of poor bioavailability by creating a liquid micellar matrix that disperses quercetin into tiny droplets, improving its absorption. This supplement, which provides 250 mg of quercetin in each easy-to-swallow liquid softgel, is an excellent choice for anyone suffering from conditions related to blood vessel constriction or seeking additional immune and antioxidant support.
Natural Factors' Quercetin 500 mg, which provides an even higher dose of concentrated quercetin, is suitable for vegetarians and vegans. Additionally, C Extra + Quercetin, which provides 500 mg of vitamin C and 250 mg of quercetin bioflavonoids in each capsule for antioxidant protection against free radicals, helps in collagen formation to maintain healthy bones, teeth, gums, cartilage, and skin. This preparation also helps protect capillaries while supporting the immune system to curb allergies and fight viruses. Whether you're aiming for prevention or additional immune and antioxidant support, Natural Factors® has quercetin forms that are sure to meet your needs!