Quercetin: Definition, Benefits & Intake

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quercetin

Definition: What is Quercetin?
What functions does the plant substance quercetin have?
What makes quercetin unique?
How much quercetin do you need per day?
When do you especially need quercetin?
Quercetin & its versatile applications
What should you pay attention to when taking quercetin?
Interaction with other medications
Which foods contain quercetin?
Quercetin as a dietary supplement
Conclusion

Definition: What is Quercetin?

Quercetin is a flavonoid and polyphenol, and therefore belongs to the group of secondary plant substances. These are chemical compounds that can only be produced by plants and, although they are not directly essential for their survival, they do have positive effects.

Quercetin is a yellow, fat-soluble natural dye. It is almost insoluble in water. Its name is derived from the Latin word "quercus", which can be translated as "oak".¹ Fun fact about its occurrence in nature: The yellow dye is found in the bark of the dyer's oak (lat. Quercus velutina), whose coloring power was previously used to dye wool and cotton.²

What functions does the plant substance quercetin have?

Quercetin is a well-researched plant substance among the flavonoids and has been tested in studies primarily for its effect as an anti-inflammatory. This flavonoid also has potential antioxidant properties, meaning it can protect the body from free radicals. It is therefore linked to mitochondrial health and well-being.³

Quercetin also has antiviral and antibacterial properties.⁴ For example, basic research has shown that this secondary plant substance could inhibit the replication of the SARS-CoV-2 virus, which caused the COVID-19 pandemic.⁵ Other health benefits of quercetin are currently being researched.

What makes quercetin unique?

Glucosamine is prescribed as a medicine to relieve stiff or swollen joints, although the exact mechanism of action is still unknown.⁴ Whether the active ingredient also has an analgesic or anti-inflammatory effect has not yet been clearly proven.⁵

How much quercetin do you need per day?

To date, the German Nutrition Society (DGE) has not issued any reference values for the intake of secondary plant substances such as quercetin. However, the German Foundation for Health Information and Prevention (DSGiP) has recommended a dosage for therapeutic applications. This is 150 to 1000 mg of quercetin per day.⁹

When do you especially need quercetin?

Quercetin is suspected of having antioxidant, antimicrobial and antiviral effects in acute infections. The substance therefore represents a possible herbal support in the fight against viruses and bacteria.

Other therapeutic and preventive applications include:¹⁰

intestinal inflammation
diabetes
asthma
rheumatoid arthritis

In phytotherapy, quercetin is used, for example, for chronic pelvic pain syndrome and chronic venous insufficiency.¹¹

Quercetin & its versatile applications

In addition to its role in nutrition and as a dietary supplement, quercetin is also used in various industrial fields and scientific research. In the food industry, quercetin is sometimes used as a natural additive to extend the shelf life of products and maintain quality. In addition, research is being conducted into whether quercetin, when combined with other ingredients, can protect the skin from premature aging and have anti-inflammatory effects, which could make it a promising ingredient in skin care.

What should you pay attention to when taking quercetin?

A dosage of up to 1,000 mg of quercetin per day is considered safe, even for long-term use. However, a higher amount can have a toxic effect and lead to unwanted side effects such as gastrointestinal complaints, kidney problems, headaches and dizziness.¹² To avoid such symptoms, you should always follow the recommended dosage of dietary supplements. This also applies to quercetin preparations.

interaction with other medications

In addition, taking quercetin may affect the effects of certain medications, including blood pressure medications, fluoroquinolone antibiotics, and digoxin, a drug used to treat chronic heart failure and irregular heart rhythms.¹³

Which foods contain quercetin?

Foods such as apples, onions, broccoli, green beans, capers and berries contain this substance. However, the quercetin content varies from plant to plant. However, when the peels are removed from fruit and vegetables, a large proportion of the healthy ingredients are lost. However, culinary herbs such as lovage and chives are also good sources of these substances. Polyphenols can also be found in wine

Quercetin as a dietary supplement

In addition to diet, quercetin can also be taken as a dietary supplement to specifically benefit from the advantages of this plant substance. However, when taking it, you should always pay attention to the recommended dosage to avoid possible side effects. It is important to pay attention to the quality of the products, as not all dietary supplements are the same. Some contain additives or inferior ingredients that could affect their effectiveness. With quercetin preparations in particular, attention should be paid to high purity and good bioavailability in order to make the best possible use of the desired health benefits.

Conclusion

Quercetin is a valuable phytochemical found in a wide variety of foods such as apples, onions, broccoli and capers. Although quercetin is readily available in the diet through the consumption of certain fruits and vegetables, it can also be obtained through supplements, especially when natural intake is insufficient. For optimal effect, it is crucial to pay attention to the correct dosage and the quality of the preparations. High-quality quercetin products without unnecessary additives and with good bioavailability help to make the best possible use of the health benefits of this natural flavonoid.

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