Antioxidants have been used to protect against damage secondary to exercise, but research results have been mixed. There has also been some debate that using high doses of antioxidants such as vitamin C and E may counteract the upregulation of endogenous antioxidant defenses that are naturally triggered in response to exercise.
Quercetin, a polyphenol, has been shown to have both strong antioxidant and anti-inflammatory properties. Recent research has demonstrated that quercetin supplementation helps mitigate some of the oxidative stress on red blood cells following exercise. However, no studies have investigated the effect of quercetin in preventing strength loss and electromyographic changes that occur during exercise.
In this study, 12 moderately active men (age 26.1 ± 3.1 years) were randomized to take 1000 mg of quercetin a day (500 mg at breakfast and 500 mg 12 hours later) or placebo and then crossed over to the other treatment after a three-week washout period. A neuromuscular evaluation was performed assessing muscle damage at baseline, after 14 days of treatment, and immediately after the exercise regimen. Subjects were taking no other antioxidant supplements or anti-inflammatory medications.
After 14 days of quercetin supplementation, participants showed a significant increase in maximum voluntary isometric contraction compared to baseline. In addition, biochemical and functional indications of muscle damage were significantly lower compared to placebo. This demonstrated, for the first time, a performance enhancing benefit of quercetin.
The results showed that quercetin supplementation can mitigate the severity of muscle weakness caused by exercise and should be considered for reducing the symptoms of discomfort and strength loss that follow intense training. Other nutrients to consider are astaxanthin and fish oil.
Astaxanthin is a red-orange carotenoid mainly produced by microalgae (haematococcus pluvialis) and accumulated in many marine organisms such as salmon, trout, shrimp, and lobster. Astaxanthin’s unique molecular structure contributes to its distinct properties, such as a higher antioxidant activity than other carotenoids. Previous research suggests astaxanthin protects against exercise-induced fatigue as it decreases oxidative stress and the inflammatory response. Since astaxanthin is incorporated into LDL and HDL and transported through the circulation, its bioavailability is enhanced when taken with dietary fat or fish oil.