A randomized trial of low-animal-protein or high-fiber diets for secondary prevention of calcium nephrolithiasis

Nephron Clin Pract. 2008;110(3):c185-94. doi: 10.1159/000167271. Epub 2008 Oct 29.


Background: The purpose of this trial was to evaluate the efficacy of a low-animal-protein diet (LAPD) or a high-fiber diet (HFD) for the prevention of calcium nephrolithiasis recurrence.

Methods: We conducted a 4-year randomized trial comparing the effect of 2 diets in 175 idiopathic calcium stone formers. Fifty-five were assigned to a LAPD (<13% of total energy derived from protein), 60 were assigned to a HFD (>25 g/day fiber) and 60 were placed on a normal diet (control group). The primary outcome measure was the time to the first recurrence of calcium nephrolithiasis. Daily urine compositions were analyzed at baseline, at month 4 (M4), M12, M24, M36 and M48.

Results: Seventy-three patients completed the trial (23 in the LAPD group, 27 in the HFD group and 23 in the control group). Recurrence was 48% (11/23) in the LAPD group, 63% (17/27) in the HFD group and 48% (11/23) in the control group (p = not significant). During follow-up, urinary calcium levels and other urine parameters did not change significantly in the 3 groups, except for a significant decrease in 24-hour urinary sulfate in the LAPD group.

Conclusions: In idiopathic calcium stone formers, neither a LAPD nor a HFD appeared to provide protection against recurrence.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Dietary Fiber / therapeutic use*
  • Dietary Proteins / therapeutic use*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Nephrocalcinosis / diagnosis
  • Nephrocalcinosis / diet therapy*
  • Nephrocalcinosis / prevention & control*
  • Nephrolithiasis / diagnosis*
  • Nephrolithiasis / diet therapy
  • Nephrolithiasis / prevention & control*
  • Secondary Prevention
  • Treatment Outcome


  • Dietary Fiber
  • Dietary Proteins