Quercetin: Plant-based Support for Allergies, Inflammation, and Immune Health

Quercetin is a flavonoid compound that is a ubiquitous part of the human diet. Present in a variety of fruits and vegetables, flavonoids are responsible for the bright colors seen in these foods. Quercetin has a bright yellow color and is abundantly found in foods like citrus fruits, onions, grapes, and berries. Flavonoids in general are well known for their antioxidant potential and, along with serving their purpose of providing bright colors, act as antioxidants in the plants in which they are found. As antioxidants, they are prolific in their ability to scavenge reactive oxygens species, or free radicals, and they also have immune-boosting, cardiovascular, anti-inflammatory, and anti-allergic potential. While the potential effects of flavonoids on human health are vast, it is unfortunate that the estimated daily intake of these compounds in Western diets are minimal, estimated at only 20-50 mg/day. This limited intake of flavonoids is unfortunately indicative of the fact that, as an overall population, we are not getting our required intake of fruits and vegetables.

Several research studies have been carried out on quercetin benefits for immune support and demonstrating its value as an antioxidant; however, its most useful benefits stem from its anti-allergic effects, in particular as an inhibitor of histamine release from mast cells. These activities lend it to be a highly crucial plant-based compound for lung and sinus health. Interestingly, studies also support powerful anti-inflammatory benefits of quercetin as well as direct antiviral effects. The mechanisms of quercetin highlighted below indicate the connection between balancing inflammation and enhancing immunity, as well as why quercetin is one of the most useful phytonutrients for health.

• Inflammatory Support and Immune Modulation

Studies in cell models have shown that quercetin is helpful for inflammation because it has powerful anti-inflammatory activity. This includes a reduction of tumor necrosis factor alpha (TNF-α) from macrophages, a key regulator of the inflammatory response. As a signaling molecule, TNF-alpha leads to a cascade of events contributing to acute inflammation and cellular damage during the mounting of an immune response. By limiting its production, quercetin can stem this cascade of events and keep cells functioning like normal. Additional research found that quercetin down-regulates release of the cytokine IL-4 from immune cells. As a cytokine or chemical messenger of the immune system, the overproduction of IL-4 increases inflammation and is associated with allergies and airway inflammation in people with lung health conditions.

Other data shows that quercetin can upregulate or downregulate several key pathways associated with the inflammatory response in human tissues, making it a versatile nutrient to balance inflammation.

• Inhibits Degranulation of Mast Cells and Balances Histamine Levels

Mast cells are a type of immune cell that are best known for their role in allergies and sensitivity reactions and contribute to other immune disorders. Mast cells contain granules that, upon activation, release chemical messengers such as histamine and heparin into circulation, along with other pro-inflammatory mediators. Quercetin inhibits the release of these inflammatory mediators from mast cells in a few ways. First, it serves to stabilize mast cell membranes, making them less prone to sensitization and release of chemical messengers. Quercetin also inhibits mast cell activation through several unique pathways, leading to an overall moderation of the allergic immune response. While mast cells are important for generalized allergic responses, they are especially important for symptoms experienced by those with asthma and sinus conditions. By preventing mast cell degranulation and promoting antihistamine activity, quercetin also prevents several downstream effects that would normally lead to the release of cytokines causing inflammation in other tissues throughout the body. Because of these functions, the use of quercetin for allergies has gained traction.

Quercetin has multi-faceted actions on the immune system through its ability to provide antioxidant support resulting in cellular protection, balance the inflammatory response by inhibiting the activation of inflammatory cytokines, and prevent the release of sensitizing chemicals such as histamine and others by directly stabilizing mast cells. These activities make quercetin an indispensable natural, plant-derived flavonoid and antihistamine compound for supporting health in individuals with allergies and asthma as well as in those with sinus issues. A good quercetin dosage for allergies is 500 mg per day, while some people may require higher amounts. Look for a quercetin supplement providing at least this much on a daily basis.

References

• Li Y et al. Nutrients. 2016.
• Kelly GS. Alt Med Rev. 2011.
• Shaik Y et al. Centr Eur J Immunology. 2018.
• Mlcek J et al. Molecules. 2016.
• David AVA et al. Pharmacognosy Review. 2016.

Tags: Quercetin, immune, immunity, lungs, sinus, histamine, mast cells, inflammation, antioxidant, airways, immune cells, cytokines, flavonoid, macrophages, antihistamine