Quercetin – For Performance and Immune Enhancement
Many of you who have run marathons or trained intensively for a race may have noticed that you become ill with chest infections or colds during the training or shortly after the race. This is not a coincidence. Marathon racing and the intensive training that it requires increases one’s risk of upper respiratory tract infections (URTI) by temporarily decreasing the function or amounts of the immune cells that would normally provide defense against them. Along with injuries and the risks of over training, infections are a major hindrance to successful training and racing.
Thus it is in the best interest of the ambitious runner to prevent infections, and there has been a great interest among endurance athletes in interventions that might reduce the risk of URTIs. Glutamine, vitamins C and E, bovine colostrum, omega-3 oils and carbohydrates have been studied for their effectiveness in preventing URTIs, but none has been shown to consistently do so. Now it seems that quercetin – a flavenoid found in fruits, berries and tea – may protect runners from illness.
Dietary flavenoids have been of great interest recently due to their anti-oxidative, anti-inflamatory, anti-pathogenic, cardio-protective, and anti-carcinogenic activities. Quercetin is the major bioflavenoid in the human diet and is absorbed well enough from the GI tract to exert wide-ranging physiological effects in humans. Significant food sources include apples, onions, berries, leafy greens, hot peppers, red grapes, and black tea.
For the past few years, the Pentagon’s research arm – DARPA – has been sponsoring studies of quercetin in hopes that it could protect US troops. “During missions, soldiers are running around for two or three days with heavy packs on. They don’t eat or sleep, and infections are as much as a problem if not a more serious issue than injuries,” says David Nieman, who led the research.
He gave 40 male cyclists either 1 gram of quercetin a day – equivalent to eating 100 apples – or a placebo, for three weeks. During that time, the cyclists spent a three day period training at maximum intensity for 3 hours each day. “By the time they were done they were just wasted,” Nieman says. Two weeks later, nine of the cyclists in the placebo group had suffered infections, compared to just one in the quercetin group.
Tests showed that the cyclists had high levels of quercetin in the blood. Previous lab studies showed that quercetin can bind viruses and bacteria and prevent their replication, as well as influencing the immune system to better respond to an attack. This is how Neiman believes that quercetin prevents infection.
Last year Nieman published an article showing that quercetin improved cycling time-trial performance by about 3 per cent, when given in combination with antioxidants, in a small study of elite athletes. He is now looking into whether quercetin can benefit people suffering from high mental stress, who are also at greater risk of infection. He is hoping to establish the minimum amount of quercetin needed to achieve these very desirable effects.
The data thus far is impressive, and the supplement appears to be safe. If you have questions about dosing schedules or the best types and brands I suggest drop me an email or give me a call. Best of luck with your training and racing!
