A flavonoid antioxidant found in plants may help reduce illness and maintain mental performance in physically stressed subjects, say researchers at Appalachian State University. They gave trained cyclists 1,000 mg per day of quercetin (plus niacin and vitamin C) for five weeks, while another group of 20 cyclists were given a placebo. After three weeks, all subjects rode a bicycle three hours per day for three days to the point of exhaustion. After the intense exercise period, about 45% of the placebo cyclists became ill, while only 5% of the quercetin group suffered any illness. The quercetin group also better maintained their ability to react after exhaustion.
Source: Vitamin Research Product News, April 2007