Hay fever season is looming, and many allergy sufferers may be wishing they had a way to prevent the misery of sneezing and sniffling. One reader made a serendipitous discovery: quercetin taken for glaucoma calmed allergy symptoms quickly. What should you know about this supplement?
Quercetin for Glaucoma and Allergies:
Q. You’ve written about NasalCrom for allergies and I ordered it with high hopes. I also have glaucoma and wanted to get off Nasacort although it is working beautifully for my nose. I also take Xyzal or Zyrtec daily. Sad to say, despite using it two or three times a day for three months, NasalCrom did not seem to do anything for my allergies.
I did stumble across a supplement that seems to help–quercetin. It may reduce the risk of glaucoma, specifically benefiting retinal cells (Frontiers in Molecular Neuroscience, Sep. 7, 2017).
Oddly, I found that it helps with allergies too! I would be verging on breakthrough sneezing and found the symptoms settle down within 20 minutes of taking quercetin. You are supposed to take twice a day. Imagine my surprise when I checked the reviews and read that others also reported relief from allergy symptoms.
What Is Quercetin?
A. Thank you so much for alerting us to this approach to managing allergy symptoms. Quercetin is a flavonoid compound that is found in many different plants. Onions, kale and apples are particularly good sources of quercetin in the diet. Capers, berries, Brassica vegetables like broccoli or cabbage, grapes and tomatoes are other foods that contain quercetin (Nutrients, March 15, 2016). Even tea has a small amount.
When we checked the medical literature, we were quite surprised to find research showing that quercetin is more effective than cromolyn (the active ingredient in NasalCrom) in blocking the inflammatory compounds released by mast cells (PLOS One, March 28, 2017). These studies were conducted in tissue cultures, and this compound might not be as effective when it is taken as a dietary supplement. However, research in rats suggests that it may ease allergic rhinitis, aka hay fever (European Archives of Oto-Rhino-Laryngology, Aug. 2017).
We’d love to see a clinical trial in humans, but they are expensive. Quercetin, as a natural compound, cannot be patented and therefore it is unlikely such a study will be conducted.