The Potent Synergy between Quercetin and Zinc

Zinc is integral to a robust immune system, aiding in the prevention and combat of infections and illnesses. It is involved in around 200 enzymatic processes, extending its functions beyond its often touted benefits for the immune system and wound healing. It supports skin health and acne reduction, while also acting as a potent antioxidant that safeguards cells from oxidative stress. Additionally, zinc contributes to cognitive function, hormone balance, and has anti-inflammatory properties that help reduce chronic inflammation. Moreover, it is essential for proper digestion and metabolism, and supports eye health, potentially preventing age-related macular degeneration.

Deficiencies in zinc cause DNA fragmentation and cell damage of lymphocytes and other immune cells in the epithelium and endothelium. Zinc alone has been found in many studies to have antioxidant and cell-protecting properties (1). 

Since quercetin forms complexes with metals like zinc, and also participates in many metabolic and metalloenzymatic processes, it has been studied in various combinations with zinc and shown greatly improved efficacy. It turns out that polyphenols can move zinc ions across cell membranes without the help of natural zinc transporters.

What is Quercetin?

Quercetin is a common flavonoid found in onions, fruits and flowers. Many studies have explored the extraordinary effects of quercetin against a variety of cancers (2). However, it has some downsides, which are the lack of absorption and rapid bodily excretion.

This has prompted investigations into improving its delivery. Some methods have included combining quercetin with lecithin or a liposomal formulation. One double-blind, placebo-controlled clinical human trial combined quercetin with lecithin to see if it had an effect on chronic fatigue syndrome. They found that daily supplementation with Quercetin 500mg improved chronic fatigue symptoms significantly (4). This highlights its wide range of activity, even for conditions not usually associated with zinc deficiency.

Why Combine Quercetin with Zinc?

To improve the already high anti-oxidant activity of quercetin, researchers have been combining it with zinc, another antioxidant, to form potent Zn-Q complexes. 

For example, a 2023 study from Japan, synthesized yet another zinc-quercetin complex (2). Using a zinc ion fluorescence probe, researchers were able to track intracellular zinc absorption, and found that quercetin proportionally enhanced the bioavailability of both quercetin and zinc, as well as enhanced their anti-cancer activity. This was one of the first to confirm that the Zn-Q complex uses the capase pathway to cause apoptosis, cell growth inhibition, and other anti-oxidant and anti-cancer effects in human liver cancer cells (2).  

In another study on bladder cancer cells, the Zn-Q complex was found to have significant effect on cancer cell death at 24 hours, as well as anti-migration and anti-invasiveness effects (3).  

Given quercetin’s wide-ranging biochemical activities, and due to its affinity to metals like zinc and iron, it holds promise for many conditions. When combined with zinc in particular, both achieve greater efficacy than when taken individually.

Quercetin Highlights

1. Antioxidant Properties: Quercetin helps fight free radicals, reducing oxidative stress
2. Anti-Inflammatory Effects: It has potent anti-inflammatory properties, which can help with conditions such as asthma and general inflammation.
3. Heart Health: Quercetin may protect against heart disease by reducing blood pressure and cholesterol levels (7).
4. Cancer Prevention: Studies suggest quercetin might help kill cancer cells and inhibit the growth of different types of cancer
5. Blood Sugar Control: It can help regulate blood sugar levels, potentially benefiting those with diabetes
6. Brain Protection: Quercetin is believed to have brain-protective effects, possibly helping with conditions like Alzheimer's
7. Exercise Performance: It has been linked to improved exercise performance and reduced exercise-induced inflammation
8. Immune System Support: Quercetin can help stabilize cells that release histamine, which may reduce allergic reactions and support the immune system.
9. Respiratory Health: It may help prevent upper respiratory infections and improve symptoms of respiratory conditions
10. Aging: Quercetin's antioxidant properties may offer protective functions against aging (6).

Zinc Bis-glycinate (DCS)

Zinc bisglycinate is a chelated form of zinc, where zinc is bound to two glycine molecules. This form is often praised for its enhanced absorption and bioavailability. Here are some benefits:

1. Enhanced Absorption: Zinc bisglycinate boasts superior absorption compared to other forms of zinc, making it more effective at raising zinc levels in the body.
2. Improved Bioavailability: The chelated form ensures that more zinc is readily available for use by the body.
3. Immune Support: Zinc is crucial for maintaining a healthy immune system, helping to fight off infections and illnesses.
4. Skin Health: Zinc plays a vital role in skin health, aiding in wound healing and reducing acne.
5. Antioxidant Properties: Zinc acts as an antioxidant, protecting cells from oxidative damage.
6. Cognitive Function: Adequate zinc levels support brain function and may help improve cognitive performance.
7. Hormone Balance: Zinc is essential for hormone production, including testosterone, and can help with hormone balance.
8. Anti-Inflammatory Effects: Zinc has anti-inflammatory properties that can aid in reducing chronic inflammation.
9. Better Digestion and Metabolism: Zinc is involved in numerous enzymatic reactions that are essential for digestion and metabolism.
10. Support for Vision: Zinc is important for eye health and may help prevent age-related macular degeneration.

You can find both high quality forms of quercetin and zinc in the Dr. Clark store:

Sources

1). Dabbagh-Bazarbachi, H., Clergeaud, G., Quesada, I. M., Ortiz, M., O’Sullivan, C. K., & Fernández-Larrea, J. B. (2014). Zinc ionophore activity of quercetin and epigallocatechin-gallate: from Hepa 1-6 cells to a liposome model. Journal of Agricultural and Food Chemistry, 62(32), 8085-8093.

2). Nakamura, M., Urakawa, D., He, Z., Akagi, I., Hou, D. X., & Sakao, K. (2023). Apoptosis Induction in HepG2 and HCT116 Cells by a Novel Quercetin-Zinc (II) Complex: Enhanced Absorption of Quercetin and Zinc (II). International Journal of Molecular Sciences, 24(24), 17457.

3). Lee, Y. H., & Tuyet, P. T. (2019). Synthesis and biological evaluation of quercetin–zinc (II) complex for anti-cancer and anti-metastasis of human bladder cancer cells. In Vitro Cellular & Developmental Biology-Animal, 55, 395-404.

4). Rondanelli, M., Riva, A., Petrangolini, G., Gasparri, C., & Perna, S. (2023). Two-month period of 500 mg lecithin-based delivery form of quercetin daily dietary supplementation counterbalances chronic fatigue symptoms: A double-blind placebo controlled clinical trial. Biomedicine & Pharmacotherapy, 167, 115453.

5). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9032170/

6). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10384403/

7). Terao J. Potential Role of Quercetin Glycosides as Anti-Atherosclerotic Food-Derived Factors for Human Health. Antioxidants. 2023; 12(2):258. https://doi.org/10.3390/antiox12020258