The Many Ways Quercetin Promotes Health

When optimizing nutritional intake, most people think of vitamins and minerals. However, there are many other compounds that may help promote health, namely quercetin.

I believe quercetin deserves more attention as a growing body of research shows that it helps optimize health in a variety of ways, including fighting cancer and viruses and repairing damage caused by oxidative stress.

Quercetin improves your antioxidant profile.

According to USA Today, “Quercetin’s primary benefit is that it is a powerful antioxidant that protects the body from cell-damaging free radicals.”¹ In fact, in a 2023 study,² Quercetin is the most powerful antioxidant flavonoid and helps protect the body against various diseases.

In one meta-analysis³ For example, quercetin has been found to help manage multiple sclerosis (MS) by combating oxidative stress. As the researchers note, oxidative stress not only causes neuronal cell death but also impairs mitochondrial function.

Oxidative stress also affects the integrity of the blood-brain barrier, promoting greater influx of white blood cells into the central nervous system. Ultimately, this process damages myelin and⁴ A layer surrounding nerves that helps transmit electrical impulses.⁵ This process worsens the progression of MS over time.

Following this framework, researchers sought to determine how effective quercetin was in managing multiple sclerosis. Based on collaborative research, here’s how quercetin protects your central nervous system (CNS):

“Quercetin reduces oxidative stress, inhibits the demyelination process, promotes remyelination potential, improves optic nerve pathway function, reduces glial activation, reduces apoptosis, strengthens BBB integrity and reduces inflammatory responses. “I can do it.”

The same study also pointed out that quercetin’s antioxidant capacity also has neuroprotective effects. Examples include “increased learning and memory, reduced mitochondrial dysfunction, reduced senile plaques, and increased oxidative defenses through AMP-activated protein kinase (AMPK) activation.”⁶

Quercetin’s cancer-fighting abilities

Quercetin has anticancer properties, according to Dr. Denise Millstine, director of integrative medicine at Mayo Clinic’s Arizona branch.⁷ This statement is also supported by published research.

In a 2023 study,⁸ Researchers noted that quercetin has therapeutic effects on blood cancer, lung cancer, and prostate cancer. It works by promoting apoptosis and autophagy in cancer cells by regulating molecular factors involved in signaling pathways.

Additionally, quercetin has an anti-angiogenic effect against cancer by reducing the proliferation of tumor-related blood vessels. It also has an anti-metastatic effect. It helps prevent the proliferation of cancer cells isolated from the primary tumor by inhibiting various molecular pathways and angiogenesis.⁹

Quercetin has been studied in a variety of animal models and human cancer cell lines. In one review published in 2022,¹⁰ It has been shown to affect leukemia, breast cancer, osteosarcoma, and pancreatic cancer. A separate study found that quercetin also targets colon cancer cells.¹¹

“Quercetin inhibited colon cancer cell growth by regulating the expression of senescence proteins, including Sirtuin-6 and Klotho, and also inhibiting telomerase activity, limiting telomere length, which was evident in qPCR analysis. Quercetin also increased proteasome 20S levels. showed protection against DNA damage.” The study authors noted.

Viruses are destroyed by quercetin

Quercetin’s reputation as an antiviral agent first began in the aftermath of the SARS epidemic in 2003. In the report¹² Published in the Canadian magazine Maclean’s, medical researchers Michel Chrétien and Majambu Mbikay began their experiments with quercetin when they discovered that it had “broad-spectrum” properties that helped it fight a variety of viruses.

During the 2014 Ebola outbreak in West Africa, they tested the theory and noted that quercetin was effective against the virus “even when administered only minutes before infection.” During the COVID-19 pandemic, Chrétien, Mbikay and other researchers have promoted quercetin as an antiviral intervention.¹³ The question is how effective is this strategy?

in research¹⁴ According to the study, published in Frontiers in Pharmacology, researchers conducted an open-label, randomized controlled trial in Lahore, Pakistan. A total of 108 patients aged 18 years or older who tested positive for SARS-CoV-2 were selected for the trial and divided into two groups. The test group received 500 mg (milligrams) of quercetin (including standard treatment) and the control group received 500 mg (milligrams) of quercetin. Only standard treatment is available.

After one week, quercetin was able to reduce viral persistence by 68% and 24% in the test group compared to the control group. This means they have tested negative for the SARS-CoV-2 virus. In conclusion, the researchers noted that quercetin accelerated recovery from COVID-19 in the test group.¹⁵

researcher of research¹⁶ A paper published in 2022 uncovered a mechanism for why quercetin is effective in inhibiting SARS-CoV-2. According to their observations, quercetin normally interacts with the hemagglutinin glycoprotein, preventing the virus from entering cells. However, in the case of SARS-CoV-2, quercetin inhibits 3-chmotypsin-like protease (3CLpro), which is required for viral replication. Another way quercetin blocks viral replication is by inhibiting the Mpro protein.

SARS-CoV-2 is not the only virus that inhibits quercetin. Other strains known to respond to quercetin include other coronaviruses, influenza, human respiratory syncytial virus (RSV), and rhinovirus.¹⁷ If you are prone to colds and flu, you may want to consider taking quercetin a few months before cold and flu season begins to boost your immune system.

Zinc enhances the antiviral effects of quercetin

Quercetin is impressive on its own, but it can still enhance its effects. One strategy is to increase your zinc intake because quercetin acts as a zinc ion transporter.¹⁸ This mechanism works by transporting zinc ions through the cell membrane and into the cell, which helps prevent virus replication.

This mechanism was observed in the study.¹⁹ Published in the British Journal of Nutrition. Although the researchers noted that the exact mechanism is not known, the following theory has been postulated.

“The antiviral function of Zn is based on the inhibition of viral protease and polymerase enzyme functions, as well as the inhibition of physical processes such as viral immobilization, infection and coating. An increase in intracellular Zn concentration interferes with the proteolytic process of viral polyproteins. You can, it affects the envelope.

Moreover, high intracellular Zn concentrations can directly affect viral proteases (picornaviruses, encephalomyocarditis and polioviruses) and change the tertiary structure of proteins, as in the case of encephalomyocarditis virus. Zn also prevents viral infection by inhibiting viral and host cell membrane fusion.”

Zinc isn’t just needed for virus protection. It is also involved in other important processes such as cell division, growth, and wound healing. According to one study²⁰ Published in the Journal of Agricultural and Food Chemistry, zinc also aids in glucose absorption and regulates energy metabolism. Not getting enough zinc impairs your sense of taste.²¹ and smell²² It may also be influenced.

Where can I get zinc? Natural sources include grass-fed beef, Greek yogurt, mushrooms, cheddar cheese, pastured eggs, and broccoli.²³ If you decide to take supplements, you should be careful about taking more than 15 mg per day. That’s because you need to absorb zinc from other foods you eat. If you already eat a lot of animal products, you may not need to take supplements at all.

That said, Dr. Chris Masterjohn points out that the ideal dosage for zinc supplementation is 7 mg to 15 mg four times daily on an empty stomach or with phytate-free food.²⁴ Be careful with your copper intake too, as an imbalanced zinc to copper ratio may negate the benefits of zinc over quercetin.

Try Dietary Sources of Quercetin

The biggest benefit of quercetin is that it is already present in many fruits and vegetables. So, if you’re eating a balanced diet, you’re likely getting it from a variety of sources. But if you want to increase your intake, Millstine points out that cranberries, dark grapes, garlic, capers and apples (with the skin) are good sources.²⁵ Additional sources include:²⁶

In the example provided above, I would like to highlight the levels of quercetin found in onions, especially their skins. According to published research,²⁷ “About 77 times more quercetin is found in onion peel than in the edible part.” This makes sense due to quercetin’s antibacterial properties.²⁸ This acts as a protective barrier protecting the rest of the vegetable from soil microorganisms.²⁹

If you don’t like the idea of ​​consuming onion peels, there is a solution. This means making a broth from onion peels to extract quercetin and other antioxidants. in research³⁰ A study published in Foods found that cooking onions increases their beneficial properties, especially when grilled, broiled, and fried. Although all methods are beneficial in increasing quercetin properties, their bioavailability varies.

“The bioaccessibility index of total phenolic compounds after in vitro digestion ranged from 42.6% to 65.5% in roasted yellow-skinned onions (YSOs) and roasted yellow-skinned onions (YSOs), respectively, and 39.8% in boiled and roasted red-skinned onions (RSOs). onion), and roasting contributed to the highest amount of bioaccessible phenolic compounds in both onion varieties after in vitro digestion.”

Should I Take Quercetin Supplements?

According to one study³¹ Quercetin, published in Frontiers in Immunology, has an excellent safety profile. Researchers noted that taking up to 1 gram (1,000 mg) of the supplement per day for three months did not cause any serious side effects. But intravenous quercetin is a different matter.

“In a phase 1 clinical trial in cancer patients, intravenous quercetin caused nausea, vomiting, sweating, flushing, and dyspnea at doses >10.5 mg/Kg (756 mg per 70 kg individual) up to 51.3 mg. Only higher intravenous doses administered (approximately 3,591 mg/Kg) were associated with renal toxicity.”

Additionally, consider increasing your vitamin C intake through food or supplements. Like zinc, vitamin C has been shown to increase the effectiveness of quercetin. The same study noted that vitamin C and quercetin “exert synergistic antiviral activity” due to their overlapping benefits. Additionally, vitamin C helps recycle quercetin, further increasing its efficacy.³² These benefits have also been confirmed in other studies.^33,34

Dosage is only half of the equation. The other half is when I take quercetin supplements. I think taking quercetin (with zinc) before bed is the best option. Also, remember that your last meal should be consumed 3-4 hours before bed. Then sleep for 8 hours.

If your metabolism is flexible, your body enters a fasting state during sleep and NADPH levels rise. As one study noted:³⁵ According to a study published in Cells, NADPH is required for the synthesis of nitric oxide, which diffuses into the mitochondria to produce peroxynitrite. From there, mitophagy occurs, which helps with neuronal metabolism and helps manage Parkinson’s disease.

Another benefit of taking quercetin at night is that it utilizes its senolytic action to eliminate senescent cells, similar to non-replicating cancer cells that secrete powerful pro-inflammatory cytokines that destroy your health. Taking it during fasting optimizes the senolytic properties of quercetin.