Do Quercetin Supplements Work For Ultradistance Athletes?

Aerobic exercise causes oxidative stress, which is a natural occurrence that results from by-products produced from oxidative processes necessary for aerobic metabolism. These by-products, which are referred to as free radicals or reactive oxygen species (ROS) are also created from the inflammatory responses to muscle injury caused by prolonged, repetitive muscle activity. It is most evident among long-distance runners whose muscles are activated eccentrically.

What Quercetin Can Do To Our Body

The problem with ROS is that they are believed to instigate muscle injury and reduce immune function, which makes some athletes more susceptible to infection. In fact, increased incidence of upper respiratory tract infection occurs among athletes during rigorous training and competition. Those athletes who engage in prolonged intense exercise will experience a significant amount of oxidative stress, which can lead to muscle injury, increased fatigue and increased susceptibility to infection.

This is where the antioxidants come in. Antioxidants are natural chemicals in the body that fight the ROS quite effectively. There are many types of antioxidants, but one type, in particular, is a group known as flavonols. Flavonols are thought to be antioxidative, anticarcinogenic, cardioprotective and anti-inflammatory. One flavanol that is getting more attention in endurance exercise is quercetin, which is naturally found in foods like berries, onions, broccoli, red wine, tea, and apples. It is getting more attention as a food supplement, usually sold in a blend containing niacin and vitamin C. It is believed that quercetin supplementation can increase the antioxidant power of the body and possibly reduce the negative effects of ROS. In fact, a group of investigators observed reduced upper respiratory tract infection among athletes consuming the supplement.

Effects of Quercetin In The Body

To test the effects of quercetin on blood oxidative capacity in response to ultramarathon competition, a group of researchers tested several athletes competing in a 160-kilometer endurance race. Sixty-three male and female athletes were recruited and placed into either a quercetin group or a placebo group. The study was randomized and double-blinded. For three weeks, athletes in the treatment group consumed 100 milligrams of quercetin, 1000 milligrams of vitamin C and 80 milligrams of niacin every day. Blood was then drawn before the race and during the first half hour following the race. The investigators tested the athletes for plasma antioxidant capacity, the first indication that quercetin is decreasing exercise-induced oxidative stress.

What they found was that flavonoid quercetin levels were 6.6-fold higher in the quercetin group compared to the placebo group, and they significantly decreased during the race in both groups. They also found that quercetin supplementation did not affect plasma antioxidant capacity, and did not later oxidative damage. With these results, the study did not find a protective effect from quercetin supplementation during ultramarathon running. Still, it might be worth the money to buy the supplements, as some studies have noted positive effects.

Get Your Quercetin Fix From Fruits

Instead of supplements, consider getting your quercetin fix from fruits and vegetables. A well-balanced diet that contains several daily servings of quercetin-rich foods like fruits, vegetables and even dark chocolate for athletes will be more likely to give you all the antioxidant power you require as an endurance athlete.