Quercetin is a naturally occurring bioflavonoid found in many plants, and is particularly concentrated in apples, red onions, and tea. It has been scientifically proven to have powerful health benefits due to its antioxidant, antimicrobial, anti-histamine, and anti-inflammatory properties. The latter two properties combine to make quercetin an excellent supplement for treatment of the symptoms of allergies.
Allergic reaction is a condition in which the body's immune system reacts inappropriately to otherwise harmless substances. The eyes and nose are usually worst affected, with sufferers experiencing cold-like symptoms-sneezing, runny nose, and watery, itchy eyes. Other symptoms can include skin rash, headache, and asthma. Allergies can be seasonal (hay fever) in which sufferers react to outdoor airborne allergens such as pollen, or year-round, in which the allergens are most likely to come from indoor sources like dust mites and animal dander or foodstuffs like wheat and eggs.
What is common to all allergic reactions is that the allergen causes a chemical called histamine to be released. This is the substance responsible for the rashes, swelling, congestion, and constriction of airways. Obviously, the best way to avoid the pain and discomfort of allergies is to avoid the allergen. But this can't always be achieved, so the next best thing to do is find a way to deal with the symptoms.
Quercetin is able to counteract these symptoms on two fronts. First, its inflammatory property lessens some of the harmful effects of the histamine that has been released. And, secondly, it acts as an anti-histamine, reducing the amount released by stabilizing cell membranes so that they become less sensitive to the offending allergens.
Experimental and anecdotal evidence suggests that quercetin is more effective as an anti-allergen when administered with the supplemental enzyme bromelain. Vitamin C has also been shown to work synergistically with quercetin to reduce the severity of allergic reactions.