N-ACETYL CYSTEINE SUPPLEMENTATION ENHANCES ANTIOXIDANT CAPACITY AND PERFORMANCE
By Jeff Volek - Chat with Doug on the
ProSource Fitness Forum
Oct 7, 2011
Intense exercise causes oxygen consumption to increase and results in the production of highly reactive oxygen species (ROS).
The ROS generated from exercise attacks lipids and other components of cells leading to muscle damage. The body has various antioxidant defense systems that counteract ROS, but these protective defense systems can be overwhelmed with exercise. Therefore boosting antioxidant status can reduce the level of fatigue and speed recovery. One of the most important antioxidant defenses is glutathione (GSH). Cysteine and thiol groups are rate-limiting for synthesis of GSH. Increased GSH translates into better anti-oxidant capacity, reduced oxidative stress and increased exercise performance. Adequate cysteine and GSH are also linked with protein metabolism either through better maintenance of protein synthesis or reduced protein catabolism. N-acetyl-cysteine (NAC) is a form of cysteine that is more efficiently absorbed and used by the body. In order to explore if short-term supplementation with NAC had any impact on exercise-induced fatigue and antioxidant capacity researchers studied 29 healthy subjects. Sixteen were randomized to receive 600 mg NAC two times per day for one week and 13 subjects received a placebo during that time. Before and after supplementation, an intense exercise test was conducted including blood draws to assess the stress response. NAC supplementation resulted in less fatigue during multiple knee extension repetitions and improved aerobic capacity. NAC supplementation also resulted in better maintenance of total antioxidant capacity in blood and resulted in less accumulation of lactate post-exercise. These results suggest that short-term NAC supplementation may be an effective in combating exercise-induced free radicals and improving performance.
Leelarungrayub D, Khansuwan R, Pothongsunun P, Klaphajone J. N-Acetylcysteine Supplementation Controls Total Antioxidant Capacity, Creatine Kinase, Lactate, and Tumor Necrotic Factor-Alpha against Oxidative Stress Induced by Graded Exercise in Sedentary Men. Oxid Med Cell Longev. 2011;2011:329643. Epub 2011 Aug 23
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