Quercetin: Second Opinion

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http://www.berkeleywellness.com/html/ds/dsQuercetin.php

 

 

Claims, Benefits: Works like an antihistamine, treats allergies, prevents heart

disease and cancer.

 

Bottom Line: Despite some promising preliminary studies, it’s too early to

recommend quercetin as a supplement. You have no idea what’s in the bottle you

buy; there could be little or no quercetin, or excessive amounts. Quercetin

absorption can vary, depending on its source. And no one knows what dose should

be taken.

 

Full Article, Wellness Letter, January 2003:

 

Quercetin: An Apple a Day

 

 

Of the 80-plus supplements included in the Wellness Guide to Dietary

Supplements, quercetin consistently ranks as one of the most visited pages. That

surprised us, so we decided to see why people are so interested. For many years

now this compound—found in apples, tea, red wine, and other foods—has been

studied for possible health benefits. Research has been accumulating, and though

it is still in its early stages, many people are jumping on the quercetin

bandwagon.

Quercetin is an important member of a large group of plant compounds called

flavonoids, once thought to be vitamins. Here are some of its potential

benefits:

 

 

• This plant pigment is an antioxidant, and thus may help fight cell-damaging

free radicals. (But like other antioxidants, it may also act as a

pro-oxidant—that is, have the opposite effects and actually become a free

radical—under some circumstances.)

 

 

• Lab studies suggest that it may have anti-cancer effects, help prevent heart

disease by reducing the oxidation of LDL ( " bad " ) cholesterol, and act as an

antihistamine.

 

 

• Specifically, it may help treat or even prevent prostate cancer by blocking

male hormones that encourage the growth of prostate cancer cells, according to

preliminary laboratory research at the Mayo Clinic. In another study, men with

an inflamed prostate (prostatitis) reported reduced urinary symptoms when they

took quercetin.

 

 

• Population studies have found that people with high intakes of foods

containing quercetin and other flavonoids tend to have lower rates of heart

disease and lung cancer.

 

 

• Several studies have linked a high intake of apples (rich in quercetin and

other flavonoids) with improved lung function and a lower risk of certain

respiratory diseases, such as asthma, bronchitis, and emphysema.

 

 

Second thoughts

 

 

That’s all promising, but it’s too early to recommend quercetin as a supplement.

First of all, you have no idea what’s in the bottle you buy. There could be

little or no quercetin, or excessive amounts. Quercetin absorption can vary,

depending on its source. And no one knows what dose should be taken. There have

been reports of supplements causing headaches and tingling in arms and legs.

Most important, no one knows what long-term adverse effects high doses may have,

or how they may interact with medication.

 

 

We do think you should get as much quercetin as you can—from foods. Apples,

onions, raspberries, black and green tea, red wine, red grapes, citrus fruit,

cherries, broccoli, and leafy greens are the way to go. And they offer lots more

than just quercetin.

 

UC Berkeley Wellness Letter, January 2003