By David Blyweiss, M.D.

Judging from the number of sneezing and congested folks streaming into my office lately, it’s shaping up to be quite a year for allergies.

If you’re among the suffering, you don’t need to stock up on antihistamines or other allergy drugs. There’s a simple remedy that helps soothe your symptoms.  Plus, it will help boost your immune system too.

Quercetin is a natural compound found in red wine, tea, onions and apples.  It works just like those over-the-counter antihistamines. Luckily, it doesn’t come with the dry mouth, drowsiness and other side effects usually associated with hay fever relievers made in a lab.

This natural flavanol calms immune cells, preventing or reducing their release of histamines. Histamines are the substances causing your allergy symptoms.

Study after study shows quercetin helps alleviate your runny nose, blocked sinuses, itchy eyes, coughs and wheezes.¹ It’s also useful for treating asthma. It strengthens the mast cells throughout the respiratory tract.

But beyond its antihistamine activity, quercetin also has strong antioxidant and anti-inflammatory properties. Here’s a quick look at this nutrient’s far-reaching health benefits:

• Boosts endurance. Researchers at the University of South Carolina tested quercetin on 12 college students who weren’t particularly active. Compared to a placebo, 500 mg of quercetin taken twice daily for seven days increased their endurance by 13.2%. It also increased oxygen utilization (a measure of cardiovascular fitness) by 3.9%.² Taking a daily dose of quercetin could be a boon for anyone suffering from fatigue—whether it’s because they are out of shape or recovering from an illness.
• Protects against heart disease. Quercetin helps keep arteries dilated. This means it reduces blood pressure and decreases plaque build-up. There’s also some evidence it can help lower LDL (bad) cholesterol levels.
• Relieves interstitial cystitis. Interstitial cystitis is bladder pain and inflammation. It’s often accompanied by an urgent need to urinate. Research at UCLA suggests that 500 mg of quercetin taken twice a day for 4 weeks can significantly reduce symptoms.³
• Eases prostatitis. Any man who has ever suffered with prostatitis—an infection of the prostate causing pain and swelling—knows it’s no picnic. But, clinical research shows that taking quercetin reduces pain and improves quality of life for men with the condition.⁴
• May reduce diabetes complications. There’s some evidence quercetin may reduce sorbitol levels. Sorbitol is a sugar that accumulates in cells and damages the nerves, kidneys and eyes of people with diabetes. Other studies suggest foods rich in quercetin can help prevent insulin resistence, better known as “pre-diabetes.”⁵
• May reduce the risk of cancer. Research published in the journal Cancer found quercetin reduces the risk of lung cancer among smokers. It also has general anticancer properties. And, in a study published in the British Journal of Nutrition, researchers also found quercetin can significantly reduce the risk for colon cancer.⁶

So how much quercetin should you take? That depends on what you’re trying to fix or prevent. Here’s a guide for the most well-established uses for this multi-talented nutrient:

For other conditions, it’s best to work with a doctor familiar with supplements. While quercetin is extremely safe, don’t take more than 1,000 mg daily since high doses may cause kidney damage.

It’s also important to talk with your doctor before taking this flavonoid if you are also on blood thinners like warfarin, corticosteroids or immune suppressing drugs.

References:

1. Chirumbolo S. The role of quercetin, flavonols and flavones in modulating inflammatory cell function. Inflammation & Allergy Drug Targets. 2010;9:263-285.
2. Davis JM. The dietary flavonoid quercetin increases VO(2max) and endurance capacity. International Journal of Sports Nutrition and Exercise Metabolism. 2010;20:56-62.
3. Katske F. Treatment of interstitial cystitis with a quercetin supplement. Techiques in Urology. 2001;7:44-46.
4. Shoskes DA. Quercetin in men with category III chronic prostatitis: A preliminary prospective, double-blind, placebo-controlled trial. Urolology. 1999;54:960-3.
5. Jung JY. Onion peel extracts ameliorate hyperglycemia and insulin resistance in high fat diet/streptozotocin-induced diabetic rats.
6. Pierini R. Flavonoids and intestinal cancers. British Journal of Nutrition. 2008;99: ES53 – ES59