Quercetin is a natural substance sometimes used to ease symptoms of seasonal allergies. An antioxidant found naturally in black tea and several foods, quercetin appears to fight inflammation (a biological process often linked to allergies). In laboratory research, quercetin has also been found to act as a natural antihistamine. To date, however, few studies have tested the effects of quercetin in people with seasonal allergies.
The Science Behind Quercetin and Allergies
Quercetin shows promise as a natural treatment for seasonal allergies, according to a 2000 report from Alternative Medicine Review. Looking at the available research on natural treatments for seasonal allergies, the report's authors found preliminary evidence that quercetin may slow up the release of histamines. Histamines are a type of chemical released by the immune system during exposure to allergens, and are known to trigger allergy symptoms like itching, sneezing, runny nose, and watery eyes.
An animal-based study released in 2007 also indicates that quercetin may help treat allergies. Published in Inflammation Research, the study found that mice placed on a quercetin-enriched diet had a decrease in inflammatory chemicals linked to allergic diseases.
Using Quercetin for Allergies
Since the evidence for quercetin's allergy-fighting effects comes from animal research and test-tube studies, it's too soon to tell whether quercetin can treat seasonal allergies in humans. Still, increasing your intake of quercetin-rich foods (such as citrus fruits, apples, onions, and teas) may help enhance your overall health by providing a range of antioxidant nutrients.
It should be noted that quercetin appears to be more effective when combined with bromelain. Bromelain, a mixture of enzymes found naturally in pineapples, seems to increase the intestine's absorption of quercetin. If you're considering the long-term use of quercetin (or any other dietary supplement) in treatment of allergies, make sure to consult your doctor before you begin taking any supplements.
Rogerio AP, Kanashiro A, Fontanari C, da Silva EV, Lucisano-Valim YM, Soares EG, Faccioli LH. "Anti-inflammatory activity of quercetin and isoquercitrin in experimental murine allergic asthma." Inflamm Res. 2007 Oct;56(10):402-8.
Shaik YB, Castellani ML, Perrella A, Conti F, Salini V, Tete S, Madhappan B, Vecchiet J, De Lutiis MA, Caraffa A, Cerulli G. "Role of quercetin (a natural herbal compound) in allergy and inflammation." J Biol Regul Homeost Agents. 2006 Jul-Dec;20(3-4):47-52.
Thornhill SM, Kelly AM. "Natural treatment of perennial allergic rhinitis." Altern Med Rev. 2000 Oct;5(5):448-54.