CORVALLIS, Ore. Flavonoids, a group of compounds found in fruits and vegetables that had been thought to be nutritionally important for their antioxidant activity, actually have little or no value in that role, according to an analysis by scientists in the Linus Pauling Institute at Oregon State University.

However, these same compounds may indeed benefit human health, but for reasons that are quite different the body sees them as foreign compounds, researchers say, and through different mechanisms, they could play a role in preventing cancer or heart disease.

Based on this new view of how flavonoids work, a relatively modest intake of them the amount you might find in a healthy diet with five to nine servings of fruits and vegetables is sufficient. Large doses taken via dietary supplements might do no additional good; an apple a day may still be the best bet.

A research survey, and updated analysis of how flavonoids work and function in the human body, were recently published in Free Radical Biology and Medicine, a professional journal.

"What we now know is that flavonoids are highly metabolized, which alters their chemical structure and diminishes their ability to function as an antioxidant," said Balz Frei, professor and director of the Linus Pauling Institute. "The body sees them as foreign compounds and modifies them for rapid excretion in the urine and bile."

Flavonoids are polyphenolic compounds with some common characteristics that are widely found in fruits and vegetables and often give them their color they make lemons yellow and certain apples red. They are also found in some other foods, such as coffee, tea, wine, beer and chocolate, and studies in recent years had indicated that they had strong antioxidant activity and because of that, they might be important to biological function and health.

"If you measure the activity of flavonoids in a test tube, they are indeed strong antioxidant
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Contact: Balz Frei
balz.frei@oregonstate.edu
541-737-5078
Oregon State University
5-Mar-2007