It has been suggested that a high animal protein intake can be associated to a risk of stone formation, due to a potential increase in urinary calcium, uric acid, oxalate and a decrease in citrate.
Creatine monohydrate is a high protein oral supplement that serves as an energy reserve in muscle cells, commonly used to enhance exercise performance.
The aim of present study was to evaluate the
effect of creatine supplementation on urinary parameters involved in stone formation in an experimental model in rats.
Seven (7) adult male Wistar rats were fed a standard chow (25g/day) supplemented with creatine (2g/kg of food) during 10 weeks. The rats were submitted to a collection of 24hr urine samples,
both at baseline and at the end of experiment for oxalate, calcium, citrate and magnesium measurements.
There was a significantly decrease in urinary citrate (8.11 1.81 vs. 11.65 2.69 mg/24h) and magnesium excretion (0.29 0.21 vs. 2.17 0.4 mg/24h).
There was a slight but not significant increase in urinary excretion of oxalate (0.47 0.19 vs. 0.40 0.11 mg/24h) and calcium (0.54 0.36 vs. 0.43 0.09 mg/24h).
These data suggest that in this experimental model, oral creatine supplementation may reduce urinary excretion of crystallization inhibitors of stone formation such as citrate and magnesium, due to its high protein content, predisposing to a higher risk of urine crystallization.
