Creatine Intake Is Not Associated With Elevated Circulating Cystatin C Levels in Individuals With and Without Kidney Dysfunction in the General Population.

Objective: The potential adverse effects of dietary creatine on kidney health are rarely addressed at the population level, particularly in individuals with preexisting kidney disease. This study aimed to evaluate the association between dietary creatine intake and serum cystatin C levels in participants with and without kidney failure, utilizing data from the 1999-2001 National Health and Nutrition Examination Survey (NHANES) round.

Method: A total of 4969 individuals (50.0% female; mean age 51.2 ± 23.9 years) who provided information on dietary creatine intake and had serum cystatin C levels measured were included in the final analysis.

Results: Linear regression across the entire sample revealed a significant inverse association between daily creatine intake and cystatin C concentrations (unstandardized B = -0.003; ß = -0.067; p < 0.001), indicating that for each additional milligram of creatine intake, the expected reduction in cystatin C levels was 0.003 mg/dL. In a subsample of respondents with kidney dysfunction, a significant negative association was found between creatine intake and cystatin C levels (unstandardized B = -0.024; ß = -0.165; p = 0.046).

Conclusions: Findings suggest that food-derived creatine does not pose a risk of kidney stress, even for individuals with kidney failure, and might be considered a renoprotective nutrient.