Quercetin
Quercetin forms an essential part of the Integrative Medical Practitioner’s armamentarium and is currently being investigated worldwide for a whole range of potential health benefits, including anti-allergy activity, anti-viral activity, strong anti-inflammatory effects, unique cardiovascular protection, and cataract prevention. It also shows some anti-cancer activity and has anti-ulcer effects.
The reason for its importance is that quercetin forms part of a range of powerhouse antioxidants called polyphenols of the flavanol group. Polyphenols are those abundant micronutrients in our daily diet, and evidence for their role in the prevention of degenerative diseases such as cancer and cardiovascular diseases is emerging worldwide.
“Over the past 10 years, researchers and food manufacturers have become increasingly interested in polyphenols. The chief reason for this interest is the recognition of the antioxidant properties of polyphenols, their great abundance in our diet, and their probable role in the prevention of various diseases associated with oxidative stress, such as cancer and cardiovascular and neurodegenerative diseases…” (Scalbert A, Manach C, Morand C, Rémésy C, Jiménez L. Crit Rev Food Sci Nutr, in press)
The richest natural source of quercetin remains onions - 1gr/kg fresh wt. - making supplementation ever favourable! You may look to add leeks and broccoli as well as blueberries to your whole food program. Red wine and tea contain close to 50 mg flavonols/L, while you can shop around for other flavonoid-rich extracts including grape seed (pycnogenol), bilberry, Ginkgo biloba, and green tea (EGCG).
From in vitro studies, quercetin has demonstrated significant anti-inflammatory activity by inhibiting both the manufacture and release of histamine (a compound released mainly by damaged mast cells in allergic reactions) and other allergic/inflammatory promoters.
In addition, it exerts potent antioxidant activity and shows vitamin C-sparing action making it an automatic supplement combination. It is known to recycle glutathione, thus protecting the liver against the damaging effects of toxic breakdown products and free radicals.
Quercetin is known to alleviate the symptoms of sinusitis, hay fever and asthma, and is also used with great success as combination treatment for gout (by inhibiting xanthine oxidase) and rheumatoid arthritis sufferers, due to its potent anti-inflammatory properties.
Its in vitro inhibition of lipid peroxidation suggests that it may lower total and LDL cholesterol (bad fraction cholesterol) levels in the body. Ongoing research is being done in this field of preventive medicine.
Quercetin supplements are available in pill or capsule form. They are often packaged with bromelain (an enzyme found in pineapple) because both are powerful anti-inflammatories.
Recommended dosage: 500-1500mg daily.
