Does long-term creatine supplementation impair kidney function in resistance-trained individuals consuming a high-protein diet?

摘要

Background The aim of this study was to determine the effects of creatine supplementation on kidney function in resistance-trained individuals ingesting a high-protein diet. Methods A randomized, double-blind, placebo-controlled trial was performed. The participants were randomly allocated to receive either creatine (20 g/d for 5 d followed by 5 g/d throughout the trial) or placebo for 12 weeks. All of the participants were engaged in resistance training and consumed a high-protein diet (i.e., ≥ 1.2 g/Kg/d). Subjects were assessed at baseline (Pre) and after 12 weeks (Post). Glomerular filtration rate was measured by 51Cr-EDTA clearance. Additionally, blood samples and a 24-h urine collection were obtained for other kidney function assessments. Results No significant differences were observed for 51Cr-EDTA clearance throughout the trial (Creatine: Pre 101.42?±?13.11, Post 108.78?±?14.41 mL/min/1.73m2; Placebo: Pre 103.29?±?17.64, Post 106.68?±?16.05 mL/min/1.73m2; group x time interaction: F?=?0.21, p?=?0.64). Creatinine clearance, serum and urinary urea, electrolytes, proteinuria, and albuminuria remained virtually unchanged. Conclusions A 12-week creatine supplementation protocol did not affect kidney function in resistance-trained healthy individuals consuming a high-protein diet; thus reinforcing the safety of this dietary supplement. Trial registration ClinicalTrials.gov NCT01817673