The Effect of Creatine Supplementation on Upper Body Strength and Immune Function in Men: 3603 Board #50 June 3 9

PURPOSE: The purpose of this study was to examine the effect of creatine (CR) loading on upper body strength and immune system function in men. METHODS: Using a double-blind design, physically active males (X age ± SD =22 ± 3 yr) were randomly assigned to a CR (n=22) or placebo (PL; n=22) group and were instructed to consume their respective treatments (20 g[BULLET OPERATOR]d-1; CR monohydrate or maltodextrin in powder form) dissolved in water over four equal time periods for 5 d. At baseline (BL) and after the 5 d loading phase, body weight (BW) and one-repetition maximum bench press (1 RM BP) were assessed. At BL and 5 d, a 50 ml blood draw was also extracted in five EDTA tubes and one serum separation tube to obtain lymphocytes and serum. Immunomodulatory effects of CR were determined using RT-PCR to analyze the mRNA expression of pro-inflammatory cytokine tumor necrosis factor-α (TNF-α), while a creatinine assay was used to measure the amount of creatinine present in the sera. Data were analyzed using 2 x 2 (group x time) repeated measures ANOVA and statistical significance for all tests was p < 0.05. RESULTS: There were no significant interactions or treatment effects for BW or 1 RM BP, however, there was a significant main effect for time with both groups demonstrating an increase in BW (PL = 0.13 kg; CR = 0.46 kg) and 1 RM BP (PL = 1.76 kg; CR = 2.06 kg). There was a significant interaction for serum creatinine, and a significant treatment effect for TNF-α mRNA levels. Post-hoc tests revealed that the CR group demonstrated a significant increase in serum creatinine levels, and significantly lower TNF-α mRNA levels after the 5 d loading phase compared to PL. CONCLUSIONS: The changes in BW and serum creatinine observed in the CR group following a 5 d loading phase are consistent with previous research. However, this is one of the first studies using human subjects to show that CR significantly reduced TNF-α mRNA expression, which suggests that it may have an anti-inflammatory effect. Future studies are warranted to further define CR as an immunomodulator and should focus on determining the expression of other pro-inflammatory mediators and markers. Acknowledgements: Supported by LB692 and MusclePharm® (CR supplement).