Does long-term creatine supplementation impair kidney function in resistance-trained individuals consuming a high-protein diet?
Level 2 - randomized trial
Individual randomized, double-blind, placebo-controlled trial
PubMed 23680457 · doi:10.1186/1550-2783-10-26
What was done
In a randomized, double-blind, placebo-controlled trial, resistance-trained individuals consuming a high-protein diet (≥ 1.2 g/kg/day) were assigned to receive either creatine (20 g/day for 5 days, followed by 5 g/day for 12 weeks) or a placebo. Glomerular filtration rate (GFR) was evaluated at baseline and after 12 weeks using 51Cr-EDTA clearance. Blood samples and 24-hour urine collections were also analyzed for creatinine clearance, serum and urinary urea, electrolytes, proteinuria, and albuminuria.
What was found
No significant differences were observed for 51Cr-EDTA clearance across 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.
Why it matters
This study provides direct physiological evidence using isotopic GFR clearance that standard creatine loading and maintenance dosing do not impair renal function in resistance-trained individuals consuming high dietary protein.
Limits
The abstract does not report the total sample size (n). The intervention lasted 12 weeks, which cannot establish multi-year safety, and the findings apply only to healthy resistance-trained adults rather than populations with pre-existing renal disease.
Cited by
- supports Multiple long randomized controlled trials show that creatine supplementation does not adversely impact kidney function.