Brazilian researchers report that daily supplements of creatine monohydrate in combination with a resistance exercise program led to a “significant increase in muscular strength”, but there were also suggestions that over-consumption could deplete some of the body’s antioxidant reserves.
“These results suggest that creatine supplementation, despite promoting acute muscle strength improvement, may be harmful as it induces oxidative stress and decreases total antioxidant status,” wrote the researchers in the Journal of the International Society of Sports Nutrition (JISSN).
“Nevertheless, further research is needed in this field to fully attest these results.”
‘Myriad of benefits’
Creatine is one of, if not the, most popular sports supplements in the world. Over 40% of athletes in the National Collegiate Athletic Association (NCAA) are reported to use creatine, according to survey data.
In addition, regular creatine supplements use in aging adults can greatly reduce muscle loss due to sarcopenia.
The new study was described as “interesting” by Jose Antonio, PhD, CEO of ISSN and Editor-in-Chief of the JISSN.
“Because of the myriad of benefits provided by creatine supplementation (including rodent data showing increased longevity), I don't know the importance of the findings in this study in a practical sense,” Dr Antonio told NutraIngrediets-USA.
“Unless someone can demonstrate that having greater oxidative stress with creatine supplementation in turn causes something of clinical significance, then in my opinion, this study will be a mere footnote in the annals of sports supplement research."
Study details
The Brazilian researchers performed a small randomized, double-blind, placebo-controlled trial with 26 elite male handball players. The men underwent a resistance training program, but were divided into three groups, and assigned to consume daily creatine monohydrate supplements (20 grams per day for four days, and then 5 grams per day for 27 days), placebo, or no intervention at all.
At the end of the study, results indicated that only men in the creatine group had an increase in muscle strength. However, they also displayed a decrease in total antioxidant status.
However, no changes between before and after values were observed for TBARS (a measure of oxidative stress), urea, creatinine, body weight and height, body fat percentage, or upper muscular area, they said.
Commenting on the TBARS data, they said: “These data suggest no involvement of oxidative stress, but one must bear in mind that a possible lack of specificity in this method and technical artifacts may overcame the differences among groups.”
“We conclude that Cr supplementation associated to a specific resistance program promotes a significant increase in muscular strength without changes in body composition,” they wrote.
“However, the significant increase in uric acid and the decrease in total antioxidant status displayed for GC subjects, suggest that Cr supplementation promotes free radical generation, and therefore, an over consumption of antioxidant reserves in order to defend themselves.”
Source: Journal of the International Society of Sports Nutrition
9:56, doi:10.1186/1550-2783-9-56
Effects of creatine supplementation on oxidative stress profile of athletes
Authors: S. Percário, S.P. de Tarso Domingues, LF. Milano Teixeira, et al.