Quercetin - Elderberry's Secret Weapon

Montana Elderberry is committed to providing the highest quality elderberry syrup products and equipping you with the knowledge to help improve your holistic health.  Our Organic Elderberry Syrup, made from European Black Elderberry (Sambucus Negra), is full of antioxidants and immune-boosting polyphenols.  One very important and powerful polyphenol found in elderberry is Quercetin.

What is Quercetin?

Quercetin is a polyphenol flavonol (plant pigment) with rich antioxidant and anti-inflammatory properties.  It is found naturally in many different flowers, vegetables, and berries, but is especially concentrated in the European Black Elderberry.  

Numerous scientific studies in both humans and animals have demonstrated that quercetin stimulates the body’s immune system in five different ways – 1. antioxidant activity in radical scavenging, 2. anti-allergic properties characterized by stimulation of the immune system, 3. anti-viral activity, 4. inhibition of histamine release, and 5. a decrease in pro-inflammatory cytokines [1].  

Quercetin also has an anti-allergic component that assists in the treatment of food and respiratory allergies, inhibiting histamine release when consumed through natural forms like berries [1]. 

As we navigate living amongst many new respiratory viruses in our society, it is crucial to integrate immune-boosting polyphenol flavonols like quercetin into our daily diets and routines.  An easy way to do that is to supplement with Organic Elderberry Syrup with 61.5mg of quercetin per serving.

What does Quercetin do?

Interest in the effectiveness of quercetin has grown exponentially over the last decade - and especially in the last couple years - as respiratory viruses and asthma are on the rise.  As a flavonol, quercetin works on a cellular level to promote natural immune system activity to ward off a variety of respiratory illnesses like cold and flu as well as cancer and heart disease [2].

The three main ways that quercetin interacts with your body’s immune system are: 1. preventing a virus from infecting healthy cells, 2. reducing the reproduction of cells that are already infected by the virus, and 3. reducing an infected cell’s resistance to various antiviral medications that may be used to treat the virus [3].

Research has also shown that quercetin may reduce inflammation in the brain that is correlated with degenerative diseases that reduce brain function [4] such as Alzheimer’s and Parkinson’s.

A 2002 study explains the unique benefit of quercetin since “few molecules are known to possess both mast cell stabilizing and gastrointestinal cytoprotective activity [5].  In layman’s terms, quercetin works with the body’s immune system to trigger an appropriate fight response to illness and inflammation.

Quercetin and Zinc

One important mineral that quercetin works with to perform its immunomodulating capacities is zinc.  Numerous studies have shown that “the major benefit of taking quercetin with zinc is that the quercetin will push the zinc into the center of the cell where the zinc can stop a respiratory virus from reproducing” [6].

Throughout the last several years, there has been interest in quercetin and zinc as ionophores.  “An ionophore is an ion carrier – a molecule that facilitates the movement of electronically charged ions in and out of cell membranes” [7]. Quercetin works to pave the pathway into the cell for zinc to enter into and work its magic.

Because elderberry is so rich in quercetin, it is no surprise that it has been shown to reduce respiratory illnesses [8], specifically when paired with zinc [9], [10].

Amazingly enough, studies have shown that zinc and quercetin also work together to reduce cancer cell growth [11].  A study conducted in 2019 demonstrated that quercetin and zinc - paired together - reduced the presence of bladder cancer [12] and likewise, a 2020 study exhibited how quercetin worked to reduce gastric cancer cells [13].

Quercetin Side Effects

Since quercetin is a naturally occurring polyphenol found in many common vegetables and berries, there is little concern for side-effects.  In very rare cases, quercetin can cause headaches or tingling in the arms or legs [14].

Like any bioactive compound, appropriate dosage and consumption is necessary for optimal absorption and immune-boosting effects. Overconsumption of quercetin can result in liver or kidney damage and those who are pregnant or breastfeeding should consult with their doctor if considering an increase in their quercetin intake through supplements.

Likewise, it is wise to seek advice from your healthcare provider if you are taking medications such as antibiotics, cyclosporine, warfarin, or drugs that directly impact the liver.  Overall, the risk of side effects are minimal for quercetin supplementation, especially when compared with the many health benefits of the flavonol.

Quercetin Rich Foods

One of the highest quercetin rich foods are european black elderberries.  For centuries, elderberry has been widely accepted as a potent and essential dietary component of natural health and immunity.  For this reason, Montana Elderberry is made with the European Black Elderberry (Sambucus Negra) which has the highest concentrations of quercetin of any in the elderberry family.

The elderberry’s history dates as far back as 400 BC, and Hippocrates, the “Father of Medicine,” called the elder tree his “medicine chest”.  Many studies have been conducted on the benefits of elderberry and supplementation with elderberry was found to substantially reduce upper respiratory symptoms.  These findings present an alternative to antibiotic misuse for upper respiratory symptoms due to viral infections, and a potentially safer alternative to prescription drugs for routine cases of the common cold and influenza.

Furthermore, research from 2011 showed that “the addition of the elderberry extract at a concentration of 10% to bacterial strains in liquid culture of the flu virus decreased the cellular growth by 70% in comparison to untreated samples” [9], further proving the antiviral and immune-boosting quality of elderberry.  Thus, elderberry is an essential way to naturally increase quercetin consumption which supports holistic health.

Several other kinds of edible plants, berries, and vegetables are also considered quercetin rich foods.  “Berry crops are great representatives of quercetin glycosides” which include strawberries, red raspberries, blueberries, cranberries, black currants, and, of course, elderberries.  Quercetin is also found in yellow onions, apples, green tea, capers, shallots, and tomatoes [15][16].

Wine lovers will also be happy to know that quercetin is found in many white and light red grape varieties!  Quercetin is the main flavonol of white wine varieties (Chardonnay, Riesling, and Sauvignon Blanc) and of some light red and rosé wine varieties (Pinot Noir, Sangiovese, and Gewürztraminer) [1]. 

Wine is known for its antioxidant properties and quercetin is a powerful component to that.  With this in mind, maybe it's time for Montana Elderberry to develop our own elderberry wine!  Yes?


How much Quercetin should I take?

When it comes to the supplementation of quercetin, studies have shown that small daily dosages are efficient in demonstrating immune-boosting effects.  Researchers at the U.S. Food & Drug Administration confirm that Quercetin is generally recognized as safe.  There are no reports of harmful side effects in animals or humans at doses of several grams per day [9].

We at Montana Elderberry recommend that the daily use of our organic elderberry syrup be 1 Tablespoon per adult and 1 Teaspoon per child, aged one year or older.  1 Tablespoon of our organic elderberry syrup contains 1534mg of elderberry and 61.5mg of quercetin.  These suggested amounts may be taken up to 4 times daily, as needed, and should be taken at the first sign of illness.

As always, we welcome your questions and will continue to strive to educate you on the many benefits of natural immune-boosting foods and flavonols like quercetin.  Quercetin truly is one of the greatest benefits of elderberry!





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  1. Hawkins J, Baker C, Cherry L, Dunne E. Black elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: A meta-analysis of randomized, controlled clinical trials.  Complement TherMed. 2019 Feb;42:361-365. doi: 10.1016/j.ctim.2018.12.004. Epub 2018 Dec
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