Onions, Tea May Offer More Quercetin than Wine

Onions, Tea May Offer More Quercetin than Wine

WAGENINGEN, The Netherlands--In a study on the bioavailability of the flavonol quercetin, researchers found that a normal serving of red wine may offer less antioxidant power than the average serving of onions or tea. In the March Journal of Nutrition (131:745-8, 2001), researchers led by Jeanne de Vries from Wageningen University had 12 men consume 750 mL of red wine, 50 g of fried onions or 375 mL of black tea for four days each, with a three-day washout period between each item. The study's authors noted that all three items contained between 14 to 16 mg of quercetin.

In comparing plasma concentrations, onions offered the highest quercetin levels, followed by wine and tea. However, in urine samples, red wine had the highest level of excretedflavonols, followed by onions and tea. Researchers concluded that "because one glass of red wine provides fewer available flavonols than one portion of onions or one glass of tea,red wine appears to be a poorer source of flavonols than these othertwo sources."

For more on this study, visit www.nutrition.org.