Dietary creatine supplementation does not affect some haematological indices, or indices of muscle damage and hepatic and renal function

Background-The use of creatine (Cr) as a nutritional supplement to aid athl etic performance has gained widespread popularity among athletes. However, concerns have recently been expressed over potentially harmful effects of s hort and long term Cr supplementation on health. Methods-Forty eight young healthy subjects were randomly allocated to three experimental protocols aimed at elucidating any potential health risks ass ociated with five days (20 g/day) to nine weeks (3 g/day) of Cr supplementa tion. Venous Mood samples were collected before and after periods of Cr sup plementation and were analysed for some haematological indices, and for ind ices of hepatic, muscular, and renal dysfunction. Findings-All measured indices were well within their respective normal rang e at all times. Serum creatinine concentration tended to be increased the d ay after Cr supplementation, However, values had returned to baseline six w eeks after the cessation of supplementation, These increases were probably attributable to increased creatinine production rather than renal dysfuncti on. No indication of impairment to the haematological indices measured, hep atic function, or muscle damage was apparent after Cr supplementation. Interpretation-These data protide evidence that there are no obvious advers e effects of acute or more chronic Cr supplementation on the haematological indices measured, nor on hepatic, muscle, and renal function. Therefore th ere is no apparent health risk associated with Cr supplementation to health y people when it is ingested in quantities that have been scientifically pr oven to increase muscle Cr stores.