Quercetin: Your savior in pollen season

What will you learn in this guide?

1. What is quercetin?

2. Foods containing quercetin

3. Intake of Quercetin

4. What Quercetin can do - The positive effects

5. Excursus: Quercetin and the thyroid

6. Quercetin levels

7. Liposomal Quercetin

1. What is quercetin?

The strong antioxidant properties of the plant substance serve in nature to protect against external environmental influences such as predators or damage caused by UV radiation.

Quercetin has gained attention in recent years. Although the plant substance has only gained popularity in recent years, it is now the subject of research interest .

Previous studies show that quercetin can be associated with a reduction in seasonal allergy symptoms, a strengthening of the immune system and a reduction in high blood pressure.

2. Foods containing quercetin

The amount of the substance in foods varies depending on when the food was harvested and how long it was stored . The quercetin content in foods can be lost over time, but also depending on the method of preparation.

Most foods rich in quercetin have an outer skin , such as the skin of an apple. If you remove the skin of the apple, there is practically no quercetin left.

These are some foods rich in quercetin:

• Apples with peel (3.6mg/100g)
• Beans (4mg/100g)
• Watercress (30mg/100g)
• Coriander leaves (50mg/100g)
• Sorrel (85mg/100g)

3. Intake of Quercetin

The quercetin content in foods can be affected by various factors , such as cooking methods, the addition of fats and the freshness of the food. In addition, the amount of quercetin contained can vary even in similar foods.

Therefore, it is difficult to determine the exact amount of this antioxidant in our food. In addition, many people have difficulty consuming enough foods or vegetables to ensure adequate levels of quercetin in their bodies.

Researchers suspect that one would have to consume 10 to 60 times the average intake of fruits and vegetables to achieve the effects observed in studies.

For example, to obtain 250 mg of quercetin from food (without taking into account the absorption rate), one would have to eat 7 kilograms of apples or 2 kilograms of onions alone. Even after consuming foods particularly rich in quercetin, it remains unclear how much of the substance remains intact and is actually absorbed by the human body.

4. What Quercetin can do - The positive effects

Quercetin is one of the most important antioxidants in our diet. Its main function is to neutralize free radicals in the body. Free radicals are substances known to trigger oxidative stress, inflammation and cell death [2].

In addition to its ability to scavenge free radicals, quercetin has a variety of effects on various signaling pathways. These effects can either activate or inhibit inflammatory markers . In addition, the substance can increase the synthesis of glutathione (the body's most powerful antioxidant) and antioxidant enzymes [3].

When the body absorbs significant amounts of quercetin, it potentially offers protection against inflammation and cell death . In addition, quercetin may assist the body in producing other helpful antioxidant molecules.

Quercetin for allergies

Research suggests that quercetin has the potential to reduce the release of substances that can trigger allergic reactions. In particular, it can reduce the release of histamine . Histamine is the molecule that triggers the symptoms of allergies, such as a stuffy nose or cough. Reducing the amount of this molecule can reduce the allergic reaction itself [4][5].

A study conducted in Japan showed that taking quercetin significantly inhibits histamine release . The effect of quercetin supplementation was almost twice as strong as that of other conventional hay fever medications at the same concentration [6].

This antioxidant could serve as a natural remedy not only for hay fever but also for food allergies .

In one study, administering a high dose of quercetin to rats allergic to peanuts resulted in a significant reduction in histamine levels . No problems with the respiratory tract, blood pressure or blood vessels occurred upon contact with the allergen [7].

Would you like to learn more about this topic? Then take a look at our blog article about allergies.

Quercetin and rheumatoid arthritis

Rheumatoid arthritis is a disease of the joints that is associated with inflammation and pain .

Quercetin, known for its anti-inflammatory and analgesic effects , is a promising agent for treating this condition. It works through several mechanisms, including regulating and inhibiting signaling pathways that trigger inflammation . One of these mechanisms is the inhibition of inflammatory markers called cytokines.

The mechanisms responsible for the analgesic effects of quercetin are not yet fully understood. However, it is likely that this is also due to the antioxidant and anti-inflammatory effects of quercetin [8][9].

A study showed a significant effectiveness of quercetin against inflammation and pain in rheumatoid arthritis.

In a study involving women with rheumatoid arthritis, administration of quercetin resulted in significant improvement in symptoms . These improvements included morning stiffness, pain, joint tenderness, and physical function. In addition, taking quercetin resulted in a reduction in TNF-alpha levels , an important rheumatoid arthritis inflammatory mediator that plays a role in rheumatoid arthritis [10].

Quercetin and brain health

Current research suggests that quercetin and mood may be related , particularly with anti-anxiety and antidepressant effects.

In mice, quercetin supplementation showed a reduction in levels of CRF (corticotropin releasing factor). CRF is a molecule in the brain that is often associated with anxiety and depression .

This reduction in CRF levels is believed to be the basis for the anxiolytic and antidepressant effects of the substance [11].

In addition, experiments with rats given quercetin not only improved cognitive abilities but also contributed to an anxiolytic effect [12].

Recent studies also indicate that the substance can help prevent Alzheimer's disease and other neurodegenerative diseases. Quercetin can therefore probably also have a positive effect on brain health.

Not all mechanisms of action are fully understood, but researchers assume that the effects are due to strong antioxidant and anti-inflammatory properties [13][14].

Quercetin and blood pressure

Quercetin has the potential to lower blood pressure through several mechanisms. One mechanism is its ability to reduce oxidative stress and inflammation . In addition, this substance can have a positive effect on the elasticity of blood vessels by improving vasodilation, which is controlled by the endothelial cells, which form the innermost cell layer of the blood vessels.

Not all mechanisms of the relationship between quercetin and blood pressure are yet fully understood. Some research studies suggest that supplementation may make a valuable contribution to blood pressure control [15][16][17].

In particular, administration of quercetin was able to significantly reduce systolic and diastolic blood pressure , with the best results being achieved with a dose of 500 mg per day [18]. Importantly, the reduction in blood pressure seems to primarily benefit people with high blood pressure , so people with normal blood pressure do not need to fear that their values ​​will suddenly drop.

In addition to its positive effects on blood pressure, the substance may offer other health benefits, such as lowering cholesterol and triglyceride levels [19].

Quercetin and competitive sports

The antioxidant is also important for competitive athletes.

A team of researchers from the University of South Carolina in Columbia (USA) conducted a study with twelve subjects who each took 500 mg of quercetin twice daily for one week.

By taking quercetin, the subjects were able to improve their maximum oxygen uptake by 3.9 percent and extend the so-called “time to exhaustion” by 13.2 percent [20].

5. Excursus: Quercetin and the thyroid

In experiments with mice, quercetin (like other secondary plant substances) significantly inhibited the enzyme deiodinase . This selenium-dependent enzyme converts the hormone T4 into the active thyroid hormone T3. Impairment of these enzymes can promote hypothyroidism .

Therefore, excessive consumption of quercetin beyond the recommended daily dose should be avoided. People with impaired thyroid function who wish to take quercetin should consult their doctor beforehand.

6. Quercetin levels

External supplementation is usually required for this antioxidant to have a significant effect[21].

An increase in quercetin levels in the blood can be observed with daily intake of 150 mg or more .

Quercetin side effects

No adverse side effects are known at low doses of supplementation[22].

7. The solution: Liposomal Quercetin

Conventional supplements such as tablets or powders containing quercetin have a very low absorption rate . If you want to increase the amount of this antioxidant with many potential benefits in your body, liposomal supplements with increased bioavailability are the best choice.

The liposomal dosage form is the best way to get the antioxidant to where it belongs in the body: into our bloodstream . When liposomes are taken, the active ingredient does not reach the liver, where it could be broken down. This means that the packaged active ingredients reach their site of action directly [24].

Thanks to the liposomal packaging, the active ingredient is also protected from the enzymes of the digestive tract and from harmful stomach acid.

The liposomal technology thus ensures almost complete absorption of the active ingredient.

1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6865076/

2) https://www.sciencedirect.com/science/article/abs/pii/S0197018615300486

3) Kellis, JT and Vickery, LE: Inhibition of Human Estrogen Synthetase (Aromatase) by Flavones. Science, 1984, 225: 1032-34.

4) Flavonoid inhibition of aromatase enzyme activity in human preadipocytes” (The Journal of Steroid Biochemistry and Molecular Biology, Volume 46, Issue 3, September 1993, Pages 381-388)

5) https://pubmed.ncbi.nlm.nih.gov/21486424/

6) https://www.msdmanuals.com/de-de/heim/gesundheitsproblems-von-m%C3%A4nnern/fortplantungsystem-des-mannes/brustkranken-bei-m%C3%A4nnern

7) https://www.prostata-hilfe-deutschland.de/prostata-wissen/guthafte-prostatavergroesserung-bph

8) https://www.rxlist.com/chrysin/supplements.htm