“Quercetin” is one of those words that pop up in medical journals and health publications from time to time. Quercetin is a bioflavonoid that is found in food and drink. One of the best sources of quercetin is red wine. Medical researchers have often wondered how the rate of heart disease in France can remain so low when much of the French diet is rich in fat and cholesterol. The researchers found an answer to this paradox in red wine and its ability to protect crucial arteries.
Quercetin is a natural antioxidant, which means that it is great for preventing free radical damage. This is the sort of damage that can cause heart disease and high cholesterol, among many other things. In this way, quercetin is thought to protect you against strokes and heart attacks.
Along with its heart-protective effects, researches have also discovered that the antioxidant may be able to stop your immune cells from releasing histamine. Histamine is the culprit that triggers your body’s defense mechanisms against an allergen, which in turn causes the symptoms of sneezing, itching and swelling. The theory is in its early stages, but results are so far hopeful. In clinical trials, quercetin is used most often to combat hay fever.
Just recently, researchers have investigated quercetin’s ability to fight respiratory infections. A randomized, double-blind placebo-controlled trial was performed to measure the influence of two quercetin doses (500 and 1,000 milligrams/day) compared to placebo on upper respiratory tract infection (URTI) rates. A large community group was recruited for the trial. Participants took quercetin supplements for 12 weeks and logged URTI symptoms on a daily basis.
While no significant group differences were measured for URTI outcomes for all subjects combined, when analyzed separately by fitness level, results told a different story. A separate analysis of participants 40 years of age and older rating themselves in the top half of the entire group for fitness level showed a 36% reduction in URTI severity and a 31% reduction in URTI total sick days in the quercetin group compared to placebo. The research team concluded that a reduction in URTI total sick days and severity was noted in middle-aged and older subjects ingesting 1,000 milligrams of quercetin/day for 12 weeks who rated themselves as physically fit.
Quercetin carries no real recommended dietary intake, because quercetin is not an essential nutrient. Therapeutically, you can take between 200 milligrams and 400 milligrams of quercetin, three times daily, but check first with your healthcare provider. Look for a form called “chalcone,” and try taking it on an empty stomach.
If taking a supplement is not the ideal way to go for you, remember that you can add foods high in quercetin to your diet. It is found in red wine, black and green tea, and these fruits and vegetables: apples, raspberries, red grapes, citrus fruit, cherries, onions, leafy salad greens, and broccoli.