Acute Creatine Supplementation Increases Anaerobic Power And Plasma Urate Antioxidant Capacity Of Male Cyclists
Medicine & Science in Sports & Exercise: May 2011 - Volume 43 - Issue 5 - pp 844-845 Souza, Tacito P. Junior
Dietary creatine (Cre) has been largely used as an ergogenic aid to improve lean body mass, strength and muscle endurance of athletes. Long-term Cre supplementation, however, has been implicated in kidney dysfunctions, body dehydration, and impaired thermoregulation during exercise. In order to minimize long-term disadvantages and concomitantly increase the antioxidant capacity of exercising muscles, acute Cre supplementation has been prescribed.
PURPOSE:To examine the effects of acute Cre supplementation on plasma antioxidant capacity, iron content and lipid peroxidation.
METHODS:Five trained male cyclists performed a Wingate test two days after obtaining their reference redox indices, and then were submitted to a 7-day supplementation program with 20 g.day-1 of creatine monohydrate, followed by another Wingate test and blood sampling at day 8.
RESULTS:Creatine supplementation resulted in an improved anaerobic performance (869.6 ± 76.0 vs 950.4 ± 80.2, for PRE and POST, respectively, P<0.05), accompanied by an increase in pro-oxidant plasma "free" iron (0.31 ± 0.14 vs 1.63 ± 0.47, for PRE and POST, respectively, P<0.05). However, a possible iron-driven oxidative insult was adequately counterbalanced by parallel increases in antioxidant ferric reducing activity in plasma (FRAP; R = 0.972), leading to a 30% lower lipid peroxidation levels.
CONCLUSIONS:Our data suggest that acute Cre supplementation improved the anaerobic performance of athletes and limited short-term oxidative insults, since Cre-induced iron overload was efficiently opposed by an increase in FRAP capacity. This increase can be attributed to an overproduction of uric acid (an end-product of purine metabolism and a powerful iron chelating agent) from energy-depleted muscles; and inherent antioxidant activity of Cre.
