Quercetin is a compound found in many plant foods that has a wide range of beneficial effects on the body. Its use in the prevention and treatment of colds is very promising. It can reduce the severity of symptoms and the number of sick days, as well as the susceptibility to upper respiratory tract infections.
Quercetin is a natural yellow pigment that belongs to the flavonoid group and is found in many plant foods. This substance has a variety of health effects and, according to several studies, it can also be used preventively and therapeutically for colds.
Researchers have found that it produces beneficial effects on the body on multiple levels. On the one hand, it has an antioxidant effect and can therefore stop the chain reaction of free radicals, which attack cells and cause oxidative stress, thus preventing cell damage.
Quercetin also has anti-inflammatory, anticancer, antiviral, anti-allergic, and heart-protective properties.
Quercetin for upper respiratory tract infections
The most common upper respiratory tract infections are colds, which often cause symptoms such as a runny or stuffy nose, as well as pain when swallowing, tiredness, or coughing.
A to study A randomized, double-blind, placebo-controlled trial showed that taking quercetin twice daily for 12 weeks (in the morning after waking up and between 2 pm and the last meal of the day) led to a reduction in symptom severity and number of days of rest. illness.
The research was carried out with people from 18 to 85 years old with different levels of physical conditioning, but the positive effect of quercetin preparations was only demonstrated in those considered physically fit and with 40 years or more.
Fewer infections after intense training
Others studies the effects of quercetin after intense exercise are highlighted, as it is associated with an increased risk of contracting upper respiratory tract infections.
A reduction in the number of cases was demonstrated when quercetin was taken 3 weeks before and 2 weeks after physical exertion.
Also was observed in mice those who received an influenza virus that quercetin could offset the increased susceptibility to infections after intense physical exertion.
Quercetin’s antiviral effects
In vitro studies (performed outside a living organism) have shown quercetin’s strong antiviral properties on adenoviruses and coronaviruses, both of which can cause upper respiratory tract infections.
Therefore, quercetin can have an extremely positive effect on upper respiratory tract infections. Due to the low risk of side effects with the correct dosage, quercetin preparations can be integrated into the prevention and treatment of colds.
It can also serve as a good supplement to prevent upper respiratory tract infections that can occur after strenuous exercise.
What is the proper dosage?
Before taking any type of supplement, it is advisable to consult a specialist about the convenience of taking it and the proper dosage. However, it should be noted that the positive effects in the studies listed above were due to a 500mg dose of quercetin twice daily for up to 12 weeks. An increase in the plasma level of quercetin has been recorded without side effects.
Quercetin can be combined with other active substances such as resveratrol, catechins or curcumin. The effects of quercetin can be enhanced by additional intake of vitamin C.
Quercetin also makes the cell membrane permeable to zinc ions. As zinc plays an important role in strengthening the immune system, these two substances can also be combined.
Choosing a Good Supplement
Be sure to choose high-quality supplements that are free of allergens (e.g., gluten or lactose) or unnecessary additives. There are pure quercetin preparations or combination preparations (eg quercetin with vitamin C).
Absorption through food such as fruits and vegetables is very healthy and cannot cause harm to the body. In the form of dietary supplements, quercetin is considered safe if a dose of 1000 mg per day is not exceeded for 12 weeks.
Quercetin in high doses (more than 1000 mg/day) can cause headache or tingling in the arms and legs. If you experience side effects from taking quercetin supplements, consult your doctor.
On the other hand, if you are taking medication, talk to your doctor before taking supplements, as this can change how the medication works and increase your risk of side effects.
Quercetin is found in a wide variety of fruits and vegetables, as well as cereals and pseudocereals. The following are particularly good sources of quercetin (per 100g of raw food):
- Capers (in a jar): 180 mg
- Love: 170 mg
- dill: 55mg
- Red Leaf Lettuce (Lactuca sativa L. var. crisp): 10-30mg
- Buckwheat: 23mg
- Asparagus: 23mg
- Cocoa powder: 20mg
- Blueberries: 15mg
- Lettuce (Lactuca sativa L. var. longifolia): 12mg
- Onion: 11-41mg
- Kale: 7mg
- Unpeeled apples: 4.5 mg
- Cherry tomato: 3.3mg
- Tomatoes: 1.6 mg
- Broccoli: 0.5-1.6 mg
Quercetin passes into the cooking water when boiled, but is not destroyed. Therefore, if you cook vegetables, use the cooking water, for example, to make sauces or soups. Vegetables are easier to steam or saute. according to a to studyquercetin content is not diminished by frying or microwaving.