Supplement Review: Quercetin

This bioflavonoid may stop the itching, sneezing and sniffling of allergy sufferers

What is it?

Quercetin (pronounced ker-see-tin) is a bioflavonoid (plant pigment) with powerful antioxidant properties. It is found in many foods, including apples buckwheat, grapes, red onions, red wine and white grapefruit. It’s also sold in supplement form.

How it works?

People with allergies have immune systems that are over-active. When a benign substance like pollen enter their bodies, their immune system overreact with a massive release of histamine, which causes blood vessels to enlarge, fluids to leak into tissues, and muscles to go into spasm. Itching, sneezing, watery eyes or inflammation can result. Quercetin reduces the intensity of these allergic reactions by preventing the immune cells from releasing histamine, according to naturopathic doctor Bradley Bongiovanni, N. D., who practices in Cambridge, Massachusetts.

Quercetin’s strong antioxidant properties also strengthen cell membranes, making them less reactive to allergens and other irritants.

Evidence

There have been no human studies of quercetin’s effectiveness as treatment for allergies. However, a few animal and laboratory studies have shown positive results. A Japanese study, published in the journal Clinical and Experimental Allergy, tested the effects of quercetin on cells from human mucous membranes. The researchers concluded that this bioflavonoid inhibited the release of histamine and might therefore prevent common allergic symptoms like runny nose.

A well publicized epidemiological study published in Thorax, examined the relationship between lung function, which can be limited in people with allergies, and the quercetin in apples. After evaluating the dietary habits of 2, 512 Welshmen ages 45- 49, researchers found that those ate five or more apples a week had significantly better lung function than men who did not.

Although scientific evidence supporting quercetin’s effectiveness is somewhat limited, many naturopathic physicians frequently treat their patients’ allergies with quercetin and report great success. Paul Saunders, N. D., Ph. D., chair of Materia Medica at the Canadian College of Naturopathic Medicine in Toronto, recommends a combination of quercetin and vitamin C to his patients before and during allergy season. While the quercetin prevents the release of histamine, the vitamin C prevents the production of histamine, he says. In the majority of his patients, the combination of the two supplements has eliminated or significantly reduced allergy symptoms.

How to Take It?

Quercetin is found in many foods but to fend off allergy symptoms, you’ll probably need more quercetin than you can get from diet alone. Take 500 to 1, 000 mg two times per day between meals. If you have seasonal allergies, start taking at least a month before your symptoms usually begin and continue until your allergy season ends. You can also take quercetin with 1, 000 mg of vitamin C two times a day (or swallow the pills with vitamin C – rich orange juice), which experts say enhances the effectiveness of the supplement. Some brand of quercetin is formulated with vitamin C.

Caveats

There are none, as quercetin has no known side effects. More research is needed to determine the effectiveness or quercetin for allergies. But in the meantime, it appears safe to try supplemental quercetin.