Quercetin (or quercitin) is a natural extract belonging to the family of flavonoids, a plant pigment that is found in different foods and plants and that for several years is experiencing a lot of interest as a nutraceutical supplement.
The properties of quercetin, in fact, make it a real antioxidant and anti-inflammatory support for our body.
Let’s see where we can find it in food, what its benefits are and the possible side effects.
Properties of quercetin
Quercetin is the subject of numerous studies published and still ongoing and is increasingly recommended as a supplement to promote the antioxidant and anti-inflammatory activity of the body, helping it to counteract the action of free radicals and cellular aging. This exceptional flavonoid acts as a real natural anti-age, particularly in combating premature aging of the skin, including the appearance of wrinkles, spots and sagging.
Skin aging
Quercetin helps to reduce the damage of solar radiation on the skin, one of the first causes of the appearance of spots, signs and wrinkles. Excessive exposure to the sun, in fact, leads to a synthesis of oxygen reactions that form free radicals, substances that alter and damage the structure of collagen synthesis and elastin in the skin.
Quercetin helps to protect against the negative action of solar radiation and several other problems related to ageing, including degenerative ones, for which scientific research is being carried out
Cardiovascular system
In addition to the recognized antioxidant properties of quercetin, the anti-inflammatory, antiplatelet and antithrombotic anti-aggregative detected by some studies that describe quercetin as a valid support for the health of the cardiovascular system. It is still commonly used to assist the treatment of:
- symptoms of venous insufficiency (cramps, swelling);
- hemorrhoids;
- varicose veins;
- capillary fragility.
It is recognized that quercetin can support the protection of blood vessels and help to avoid edema and heaviness in the legs. This flavonoid is also valuable as a support to prevent urinary tract infections and inflammation of the prostate, which can affect men.
Allergies
Very interesting factor inherent in the immune system is the potential of quercetin to reduce the symptoms of major allergies, for example pollen, because it seems that the substance is able to inhibit the stages that determine the release of histamine.
Anti-inflammatory activity
Quercetin is finding more and more space also as nutraceutical adjuvant in pharmacological anti-inflammatory therapies, helping to inhibit the production of prostaglandins and leukotrienes that have a pro-inflammatory action.
It can be taken as a support in the treatment of rheumatoid arthritis, psoriasis, systemic lupus erythematosus (chronic autoimmune diseases), Alzheimer’s disease, arteriosclerosis and insulin resistance syndrome.
Foods with quercetin
Several foods commonly present on our table are rich in quercetin. This flavonoid is present in particularly high concentrations within:
- apples;
- red fruit
- fruit of the forest;
- grapes;
- citrus fruit;
- tomatoes;
- broccoli;
- asparagus;
- capers and capers;
- onions;
- red wine;
- green and black tea.
The dose of quercetin in food varies according to the cultivation method. The ideal is always to choose organic foods, so as to ensure an optimal amount of flavonoids.
Side effects and interactions
Quercetin has very few known side effects. Despite this, it is important to remember that it is not exempt from being able to determine the appearance of pharmacological interactions to be taken into account. Subjects with blood clotting diseases should pay special attention due to the platelet-like and antithrombotic activity of quercitin.
Patients who are taking platelet-inhibiting drugs (such as aspirin and cardioaspirin), oral anticoagulants (such as Coumadin and Sintrom) or are taking chemotherapy therapies should avoid their use. Its use is also not recommended to pregnant or breastfeeding women because, for now, there is no news on the possible effects on the fetus and the child.
Doses
Quercetin has a low bioavailability, therefore, it is very difficult to take an optimal amount to benefit from it only with the diet.
For this reason, supplements come into play, which typically have a recommended dose of about 200 mg/day.
References
- The effect of quercetin supplementation on selected markers of inflammation and oxidative stress, Gholamreza Askari, Reza Ghiasvand, Awat Feizi, Syed Mustafa Ghanadian, and Jahangir Karimian, J Res Med Sci. 2012 Jul; 17(7): 637-641.
- Overviews of Biological Importance of Quercetin: A Bioactive Flavonoid
Alexander Victor Anand David, Radhakrishnan Arulmoli, and Subramani Parasuraman, Pharmacogn Rev. 2016 Jul-Dec; 10(20): 84-89. doi: 10.4103/0973-7847.194044 - What are the benefits of quercetin? Medically reviewed by Alan Carter, Pharm.D. — Written by Beth Sissons on January 14, 2019, medicalnewstoday.com
- The Influence of Quercetin on Exercise Performance and Muscle Mitochondria, Jacob Schor, ND, FABNO, May 2010, www.naturalmedicinejournal.com
- What Is Quercetin? Benefits, Foods, Dosage, and Side Effects, Ryan Raman, MS, RD, June 27, 2019, www.healthline.com
- Quercetin - Penn State Hershey Medical Center - ADAM, http://pennstatehershey.adam.com
- Impact of quercetin on systemic levels of inflammation: a meta-analysis of randomised controlled human trials, Qiaowen OuORCID Icon, Zhifen ZhengORCID Icon, Yongyi ZhaoORCID Icon & Weiqun Lin, Pages 152-163 | Received 01 Feb 2019, Accepted 01 Jun 2019, Published online: 18 Jun 2019, https://doi.org/10.1080/09637486.2019.1627515
- A Review of Quercetin: Chemistry, Antioxidant Properties, and Bioavailability, Alexandra B. Bentz, Appalachian State University, 2009, Journal of young investigators, www.jyi.org
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