What is Quercetin? The 2022 guide

Introduction

What is Quercetin? It is a pigment, which belongs to an important class of plant compounds known as flavonoids. They are found mainly in grains, fruits, wine, tea, and vegetables. Flavonoids provide several health benefits to humans such as decreasing the risk of several diseases including brain disorders, heart problems, and cancer. Let discuss what it is used for.

The potential benefits of flavonoids are due to their antioxidant properties. Antioxidants are those substances, which can reduce the oxidative stress of the body by neutralizing free radicals. According to research, free radicals are unstable compounds, which can result in cell damage if their level becomes too high. And the cellular damage caused by free radicals can result in several chronic problems such as cancer and diabetes.

A study has shown that quercetin is the most common flavonoid, which is present in the human diet. Almost an average individual utilizes 10 to 100 mg of quercetin through different food sources per day.

Foods that are high in quercetin include grapes, citrus, capers, berries, coffee, onions, green tea, apples, and red wine.

Let’s discuss how this phytochemical provides health benefits to your body:

Health benefits of quercetin

It provides a wide range of health benefits, some important science-based benefits of quercetin include the following:

Can reduce inflammation

Free radicals can do great damage to your body's cells. The research presents that too many high levels of free radicals can activate the genes that promote inflammation. So, a high number of free radicals lead to more inflammatory responses in your body.

In several test-tube studies, quercetin significantly reduced inflammatory markers in the human cells. These markers were interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNFα).

One more study on fifty females suffering from rheumatoid arthritis was done to check the anti-inflammatory effect of quercetin. The results found that patients who consumed 500 mg of quercetin per day observed a significant decline in morning pain, stiffness, and after-activity pain. Therefore, observed a decrease in inflammatory marker TNFα as compared to the control group.

Can reduce symptoms of allergy

According to health experts, the anti-inflammatory properties of quercetin can also help in relieving allergy symptoms. Several animal and test-tube studies depicted that quercetin can reduce allergy symptoms by blocking histamine activity. Because this chemical plays a crucial role in promoting inflammation in the human body.

Another research found that quercetin supplementation can significantly reduce peanut-related allergic reactions in mice.

Have anti-cancerous properties

Due to antioxidant activity, quercetin has a strong anti-cancerous effect. A review of several studies has shown that quercetin can suppress the growth of prostate cancer by inducing apoptosis (programmed cell death).

Another study found that quercetin has the same impact on adrenal, liver, lymphoid, breast, blood, ovarian, lung, and colon cancerous cells. Though these studies are promising but human studies are required before using quercetin for cancer treatment.

Can prevent brain disorders

Research reflects that antioxidant properties can also prevent the risk of brain disorders in humans such as dementia and Alzheimer’s disease. In a study, rats suffering from Alzheimer’s disease get injections of quercetin every two days for three months. At the end of the research, quercetin injections significantly reduced numerous Alzheimer’s markers, and in the learning test mice showed better performance.

In another research, a diet rich in quercetin decreased markers of Alzheimer’s disease and also enhance brain functions at the initial stages of the disease. However, a diet had less effect on the animals with the disease in the middle stage.

Coffee is a famous beverage that can significantly reduce the risk of Alzheimer’s disease. Research has shown that quercetin is the main component found in coffee, which is responsible for the protective effect of this disease.

Can reduce blood pressure

Hypertension effect almost every 1 in 3 adults in America. It enhances the risk of heart problems, which is the leading cause of death in the United States. Research has shown that quercetin can reduce blood pressure levels in the human body. In several test-studies studies, quercetin lowered blood pressure by inducing a relaxing effect in the blood vessels.

In one study, hypertensive mice were given quercetin supplements for five weeks. The results depicted a significant decline in the values of diastolic and systolic blood pressure by 23% and 18%, respectively.

Similarly, one more study has found that daily supplementation of 500 mg of quercetin can reduce blood pressure in mice. Results reflected that both diastolic and systolic blood pressure were decreased by 2.6 and 5.8-mm Hg, respectively.

Our Senescent cells have a weakness.

It's a no-brainer that these cells need some downtime. They've put quite a lot of time and effort into it. Cells that have been dormant for a long time might suddenly spring into action and cause problems for others. This is how you may picture it: When an elderly cell yells into the megaphone "I'm old and thus do not have to work any longer - you could do the same," everyone looks at the microphone in disbelief. Neighboring cells, hearing this, decide to call it quits as well. As a result, a negative cycle is set in motion.

Because of this, it makes sense to replace these senescent cells with functioning ones. As a source of new cells, our stem cells have already begun to fill the space. Because quality is more important than quantity. Our quercetin assists the body in eliminating these ageing cells and targets the cells' weak spot in the process.

The role of Quercetin

The challenge here is to differentiate between cells that are still working and those that have been there for a long time. Whereas working cells are completely focused on their tasks, the elderly are clinging to the little life they have left.  They fight against cell death by activating survival factors and suppressing self-destructive signals. Senescent cells are protected from the constant bombardment of arrows by this metabolic protective barrier, allowing them to carry out their actions. Quercetin and other senolytically active molecules are carried into the cell via the protective barrier and can disable the defense shield from the inside. The enzyme PI3 kinase is blocked in this way. This breaks the survival cycle, allowing the senescent cell to die peacefully and free up space for future cells.

Dosage and food sources

Naturally, it is present in plant foods, typically in their peel and outer layer. Good dietary sources include:

• Cherries
• Broccoli
• Onions
• Kale
• Red apples
• Tea
• Berries

The level of quercetin in food mainly depends on the condition in which they are grown. For example, tomatoes have more quercetin (about 79%), if they were grown conventionally.

Quercetin supplements

Quercetin supplements are available in several forms including powders and capsules. A typical dose range of quercetin is 500 to 1000 mg each day. But it has low bioavailability, which results in poor absorption in your body. That’s why, quercetin supplements also have other compounds, like bromelain (digestive enzyme) and vitamin C to enhance its absorption. In addition, quercetin has a synergistic impact when combined with other flavonoids including catechins, resveratrol, and genistein.

Side effects and safety of quercetin

Quercetin found in vegetables and fruits is safe to eat. In the form of supplements, it is safe to consume with minimal side effects. However, in some cases consuming more than 1000 mg of quercetin daily can result in a tingling sensation, headache, and stomach discomfort.

In the form of food, quercetin is safe for lactating and pregnant women. But there are limited studies on the safety of quercetin supplements in pregnant and lactating mothers. So, before taking quercetin supplements, first, consult your physician to prevent the side effects.

The bottom line

Quercetin is the most common flavonoid found in plant-based foods. It provides several health benefits to your body. But high doses of quercetin supplements can result in minimal side effects. So, first, consult your physician before taking its supplements.

References

1. https://pubmed.ncbi.nlm.nih.gov/28620474/ 2. https://pubmed.ncbi.nlm.nih.gov/18417116/ 3. https://pubmed.ncbi.nlm.nih.gov/23675073/ 4. https://pubmed.ncbi.nlm.nih.gov/18827577/ 5. https://pubmed.ncbi.nlm.nih.gov/23044824/ 6. https://pubmed.ncbi.nlm.nih.gov/27710596/ 7. https://pubmed.ncbi.nlm.nih.gov/27187333/ 8. https://www.spandidos-publications.com/or/33/6/2659 9. https://pubmed.ncbi.nlm.nih.gov/27479153/ 10. https://pubmed.ncbi.nlm.nih.gov/11063442/ 11. https://pubmed.ncbi.nlm.nih.gov/29127724/