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Quercetin
DESCRIPTION
Quercetin belongs to the class of Bioflavonoids, which consists
of water-soluble plant colouring agents. It is a natural antioxidant
found in red wine. Quercetin protects the cells of the body
from free radical damage. It may help prevent heart disease
and Strokes by preventing free radical damage to blood vessels.
Quercetin is also recommended as a treatment for allergies
and related conditions.
SUGGESTED INTAKE
200 to 400 mg three times
daily.
Quercetin is better absorbed
if taken on an empty stomach.
SUPPLEMENTAL USES
Allergic conditions:
Quercetin is most popularly used as a treatment for allergic
conditions, including Asthma, Hay Fever, Eczema, and Hives.
Animal research has shown that quercetin blocks histamine
release by immune cells (1). However, there is no evidence
available to demonstrate the effectiveness of quercetin supplements
in treating Allergy symptoms.
Heart health:
Preliminary evidence indicates that quercetin may help prevent
heart disease and Strokes (2,3).
SAFETY
Nursing and pregnant women,
young children, and patients with serious liver or kidney
disease should take caution with quercetin, since maximum
safe levels have not yet been established for these groups.
INTERACTIONS AND CONTRA-INDICATIONS
There are no known drug
interactions or contra-indications for quercetin.
FOOD SOURCES
Quercetin is found in red
wine, grapefruit, onions, apples, and black tea. It is also
found in lesser amounts in leafy green vegetables and beans.
However, to obtain therapeutic dosages, one needs to take
supplements.
REFERENCES
1. Ogasawara H and
Middleton E Jr. Effect of selected flavonoids on histamine
release (HR) and hydrogen peroxide generation by human leukocytes.
J Allergy Clin Immunol 75: 184, 1985.
2. Constant J. Alcohol, ischemic heart disease, and the French
paradox. Coron Artery Dis 8: 645-649, 1997.
3. Keli SO, et al. Dietary flavonoids, antioxidant vitamins,
and incidence of Stroke: the Zupthen study. Arch Intern Med
147: 637-642, 1996.
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