Milk binds up the flavonoids, causing them to pass through the intestinal tract without apparent antioxidant benefit. Even better, numerous studies have shown that flavonoids work synergistically with vitamin C and E to inhibit free radial damage to our cells and tissue. Polyphenols are rapidly absorbed into the blood stream, approximately 30 minutes after ingestion. This is great for athletes, because they can eat or drink fluids high in flavonoids immediately before or even during exercise. This assures a high blood concentration of these important antioxidants while exercising.
Several vegetables have high concentrations of polyphenols including spinach, broccoli and onions.
Sesame seeds, oats, buckwheat and soybeans also have high quantities of flavonoids. The freezing process seems to preserve the polyphenol antioxicants. Oranges, grapefruit, prunes and raisens are great snacks for an athlete because they're convenient, easily stored and have a long shelf life. Ingesting flavonoids in a supplement is safe and effective.