Increasing water intake by 2 liters reduces crystallization risk indexes in healthy subjects

Arch Ital Urol Androl. 2011 Mar;83(1):43-50.


Objective: The objective of the present study was to evaluate the effects of drinking 2 additional litres of water/day on several urinary risk factors for lithiasis in healthy subjects, through measurement of crystallization risk indices (Tiselius CRI).

Materials and methods: 48 healthy subjects, aged 25 to 50 were studied for urinary parameters including CRI in the laboratory ward, for 24 hours. After this first period, they were randomized either to a 2L/d additional water intake (treated group) or usual fluid consumption (control group) for a 6 days period, which ended by a second measurement period in the laboratory ward for 24 hours.

Results: Total additional water intake was actually 1.3L/d on average in treated subjects, because subjects decreased other usual sources of fluid intake. In 24 hour urine, Tiselius CRI varied differently among treated subjects and controls between the 2 periods; male controls subjects experienced much higher values (above 2 in average in first morning urine sample) in the second period (p = 0.05). Of interest, in a transversal analysis, we observed a positive relation between BMI or waist circumference on the one hand, and with 24 hour urea excretion or osmotic load on the other hand.

Conclusion: These results show a beneficial effect of a final 1.3L additional water intake on Tiselius CRI in healthy subjects.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Crystallization
  • Drinking*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Risk Factors
  • Urolithiasis / prevention & control*