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Quercetin-rich food sources for immune support

Quercetin's Immune Support Properties

Article Summary:

  • Quercetin provides immune support properties by acting as an antioxidant and helping to maintain the body’s normal response to inflammation.* 

  • The potential benefits of quercetin are significantly restricted because the body absorbs it poorly.

  • When combined with zinc and vitamin C, quercetin has shown promising effects of synergistic protection that helps balance overactive immune responses.*

Flavonoids are a class of phytonutrients found naturally in various fruits and vegetables and are known to help the body fight off free radicals. Lately, there has been a growing scientific interest in examining how flavonoids influence multiple biological pathways and immune functions. As a flavonoid, quercetin is well known for its antioxidant activities in scavenging free radicals and supporting the body’s natural inflammatory response.* Natural sources of quercetin include berries, grapes, apples, cruciferous vegetables, onions, shallots, tomatoes, tea, and other plant products.

Below, we discuss how your body could benefit from quercetin’s immune support properties and why you should consider incorporating this antioxidant into your diet in nutritional supplement form.

How Do Quercetin’s Immune Support Properties Work?

Quercetin's various forms include methylated quercetin, quercetin sulfate, quercetin glucuronide, and quercetin glycoside. Specific properties of the glycoside group enhance quercetin's water solubility, making it more absorbable than other forms. As an antioxidant, quercetin’s beneficial effects on the body’s immunomodulatory pathways increase its potential for immune function support.* Let’s take a closer look at how quercetin’s immune support properties work. 

Quercetin’s Immune Function Support Properties
Antioxidant Effects*Immunomodulatory Effects*
Quercetin’s molecular structure is credited1 with its higher efficiency in scavenging free radicals.*  Quercetin mainly confers3 immune support by up-regulating the activity of leukocytes — the body’s natural defense against invading organisms.* Quercetin also exerts its immuno-supportive activity by benefiting intracellular signaling pathways, enzymes, and membrane proteins.*
As a potent lipid oxidation inhibitor, quercetin helps suppress the start of chain oxidation and propagation of free radicals.*Research studies4 show that quercetin’s role in stabilizing mast cells and gastrointestinal cytoprotective activities benefits immune function.*   
Quercetin’s endogenous antioxidant properties modify2 a range of cellular injury by free radicals.* Studies find5 quercetin influences dendritic cell functions — initiator and master regulator of antigen-specific immune responses.*  

Various studies indicate quercetin is primarily absorbed in the upper segment of the small intestine and later metabolized in multiple organs, including the liver, small intestine, colon, and kidney. However, quercetin is known for its poor oral bioavailability. Only 3% to 17% of quercetin glucoside — the most absorbable form — gets absorbed in healthy individuals after ingesting 100 mg. Although onions are known to be the highest natural source of quercetin, clinical trials show that after consuming an onion-rich meal, quercetin values peaked from baseline values after 2 hours, only to decrease to baseline again after 24 hours.

Zinc enhances quercetin's therapeutic benefits on several enzymes involved in the body’s immune responses.* Quercetin also acts as an ionophore for zinc — creating channels in cell membranes to enhance intracellular zinc concentration.* Promising evidence suggests a synergistic protective effect of a quercetin, zinc, and vitamin C complex in benefiting the body’s natural immune responses.*       

A Quercetin Supplement to Support Your Immune Function

QuerciSorb® Immuphore SR is an innovative supplement formulated with a soluble form of quercetin to support healthy immune function.* Developed by Tesseract Medical Research, the supplement contains other bioactive ingredients, including zinc, vitamin C, and vitamin D, to support the immune system's optimal functioning.*

Tesseract's proprietary CyLoc - DexKey® nutrient delivery technology enables the ground-breaking delivery of quercetin molecules through the gut wall, one molecule at a time, for unprecedented quercetin absorption in the body. The CyLoc® technology encases each quercetin molecule to maintain its integrity during transit through the stomach. The DexKey® technology accompanies each CyLoc® molecule to release the active ingredient molecule at the desired point within the gastrointestinal tract. The result is maximum absorption and effectiveness for each quercetin molecule, making it a bioavailable therapeutic reality to support immune function.* 

The power of Tesseract supplements lies in enhancing palatability, maximizing bioavailability and absorption, and micro-dosing multiple nutrients in a single, highly effective capsule. Shop products on our website and learn more about how they can help support immune health.*

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1Rice-Evans CA, et al. Free Radical Research vol. 22,4 (1995): 375-383. doi:10.3109/10715769509145649

2Mlcek J, et al. Molecules (Basel, Switzerland) vol. 21,5 623. 12 May. 2016, doi:10.3390/molecules21050623

3,4Chirumbolo S. Inflammation & Allergy Drug Targets vol. 9,4 (2010): 263-285. doi:10.2174/187152810793358741

5Huang RY, et al. Journal of Immunology (Baltimore, Md.:1950) vol. 184,12 (2010): 6815-6821. doi:10.4049/jimmunol.0903991

6McAnlis GT, et al. European Journal of Clinical Nutrition vol. 53,2 (1999): 92-96. doi:10.1038/sj.ejcn.1600682
7Sahib HB, et al. Advances in Virology vol. 2022 1575605. 8 Jun. 2022, doi:10.1155/2022/1575605

Al Czap, Founder | Tesseract

Al Czap has more than four decades of professional experience in preventative medicine. He founded Thorne Research in 1984 (sold in 2010) and he published Alternative Medicine Review for 17 years beginning in 1996. AMR was a highly acclaimed, peer-reviewed, and indexed medical journal. Al was the first to recognize the need for hypoallergenic ingredients and to devise methods of manufacture for and delivery of hypoallergenic products to underserved patient populations. His work has greatly impacted those with impaired immune and digestive systems and compromised health due to environmental exposures.

The advanced formulations based on our revolutionary, patented, and patent-pending technology are only available through Tesseract. No other medical, pharmaceutical, or supplement company is licensed to utilize our proprietary technology.
*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.
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