Quercetin — why and how to take it

No wonder they say that in the 21st century, food is a common cause of diseases. People live in the era of “instant people” when food is delivered quickly. However, we know that haste is the wrong adviser. Such explicit actions that form eating habits do not go hand in hand with the quality of the food sources provided. Snacks in the form of bread, fast food, sweets and energy drinks prevail.

Quercetin and inflammation

How does inflammation occur in the body

The deterioration of health is associated with the opening of the intestinal barrier, as a result of which substances from food products and additives in them are recognized as an enemy molecule, that is, an antigen. In such a situation, the uncoordinated immune system begins to fight the intruder, which often leads to an increase in pro-inflammatory cytokines, such as IL-2, IL-6 or IFN-gamma. The inflammation accompanying the performance of heavy training seems to be a desirable phenomenon. This leads to tissue reconstruction and allows you to build strong muscles. However, it is necessary to separate the inflammation accompanying micro-injuries of muscle mass with a thick line. It arose after intensive training, from chronic inflammation, which is compared to a fire that cannot be extinguished. Inflammation occurs as a result of:

  • injury;
  • when the integrity of the tissue is disrupted due to a sudden unfavorable force vector;
  • improper oral hygiene, when caries, dry holes and infections associated with root canal treatment cause inflammation;
  • parasitic infections, sometimes difficult to diagnose due to the relatively low sensitivity of tests, increased permeability of the intestinal barrier, when elevated levels of markers such as zonulin or alpha-1-antitrypsin, show the scale of the problem.

Given the lifestyle of a person, a common cause of chronic inflammation is a diet with stimulants, coffee, alcohol and energy drinks. As well as anti-nutritional ingredients, including sugar, wheat, trans fatty acids. A lot of food lectins and dairy products. Pharmacotherapy, including NSAIDs, antibiotics and PPIs, also negatively affects the microbiome. The resulting intestinal damage is corrected as soon as possible with the help of a properly selected dietary therapy, which consists of an elimination-rotation diet and intestinal barrier restoration therapy based on the use of antioxidants, probiotic drugs, colostrum and short-chain fatty acids. Sometimes they start a natural anti-inflammatory – it’s safe for our intestinal ecosystem. This raises the question of flavonoids such as quercetin. This compound is known for its beneficial effect.



Quercetin, classified as a flavone, also represents flavonoid compounds often used in pharmacy. Due to its structure, quercetin is considered an example of how spatial structure affects the biological properties of chemical compounds. The presence of a double bond in the C-ring enhances the antioxidant properties of quercetin. The presence of a hydroxyl group in the positions 3, 5, 7, 3 ‘, 4’ it not only affects the antioxidant properties, but also increases the chelating ability of divalent metals. This is important because chelation of divalent cations that catalyze oxidation periods affects the inhibition of oxidative processes, which more often have a negative effect on cells.

Acting multidimensional, quercetin enhances the protective actions taking place in the body, and the main thing is the regulation of epigenetic changes in the body. This phenomenon refers to processes that occur as a result of changes in gene expression, and not the genetic code itself. This means that epigenetic changes caused by environmental factors are associated with the development of tumor diseases. Following this example, it turned out that substances that control epigenetic changes have a positive effect on reducing the likelihood of cancer and support the treatment period. The results of recent studies show that methylation of several types of tumor suppressor genes have an effect on the state of cancer. Quercetin has demonstrated the ability to inhibit the methylation of suppressor genes. The ability of quercetin to inhibit and demethylate these genes may help both in the prevention and treatment of cancer.

Another function of quercetin in cancer is that quercetin helps normal gene transcription. This is the first step towards the expression of the P53 gene, also popular as a tumor suppression gene. The function of suppressor genes, as the name implies, is to protect cells against malignant neoplasms and the formation of tumors. Disorders of the P53 gene suppressing the tumor seem to be a common anomaly observed in human cancer, as it was already demonstrated in 1998 by Bray, Shorl and Hall. Administration of quercetin to humans leads to increased transcription of the P53 tumor suppression gene due to stimulation by a substance called Nrf2. Helps regulate gene expression. In addition, quercetin has antioxidant abilities. Although small concentrations of this flavone have an antioxidant effect, excessive concentrations cause pro-oxidant effects. These oxidative effects are beneficial because the action appears to be anti-cancer- which means inhibit the growth of cancer. An excessive concentration of quercetin leads to oxidation to substances called o-quinones. These compounds have demonstrated the effect of apoptosis, programmed death, of cancer cells, closely related to the reaction of tyrosinase with quercetin to form o-quinones, which then exhibit an anticancer effect on melanoma cells, as was confirmed in 2016 by Harris.


Products containing quercetin

A significant value of the flavonoid (Quercetin) can be obtained from various types of plant products, including, according to Sima Bhagwat, David B. Haitowitz and Joanna M. Holden (retired) published in the Database of the US Department of Agriculture on the content of flavonoids in individual foods from 2012, quercitin is concentrated in the peel or outer layer of vegetables and fruit.

Good sources of substance intake into the body of substances are:

  • Bulgarian pepper;
  • Onion;
  • Capers;
  • Berries, including cherries, cranberries, blueberries, raspberries;
  • Cabbage (white cabbage, broccoli);
  • Asparagus in the composition of dishes;
  • Tomatoes;
  • Red apples and grapes;
  • Red salad;
  • Green and black tea varieties.

Undoubtedly, the production of quercetin from products is natural for humans, but it must be taken into account that the content of the substance in various plant sources often differs. It depends on the conditions in which the product is being pulled out. Eg. According to data published by Alison E. Mitchell, Yoon-Jung Hong et al. in the journal of Agricultural and Food Chemistry, published by the American Chemical Society, the test results showed that organic tomatoes contain 79% more quercetin in comparison with tomatoes, which were cultivated by traditional methods. Also, there are studies showing that the content of this substance can vary depending on the varieties without depending on the method of cultivation.

Products containing quercetin

Consequently, there is no complete confidence in the amount of useful nutraceuticals that a person will receive from food. It is guaranteed that you can get the necessary amount of the substance exclusively from special dietary supplements and preparations.

Preparations with quercetin

Both complex supplements with quercitin and mono-preparations are presented on the pharmaceutical market.

A striking representative of complex dietary supplements is the quercetin Complex with Ester-C Plus from the American manufacturer Solgar in capsules.

Solgar Quercetin complex contains 500 mg of the bioflavonoid quercetin in combination with Vitamin C (Ester-C Plus) and the presence of bromelain (50 mg) and is supplemented with citrus bioflavonoids, rutin and rosehip. Is an excellent source

antioxidants and supports the immune system.

In addition to capsules and tablets, quercetin in granules is widely represented.

Attention, with overdoses of drugs with quercitin, symptoms occur in the form of a rash and itching of the skin. In such cases, specialists suggest discontinuation and desensitizing therapy.

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