Higher Dietary Acid Load Is Associated With an Increased Risk of Calcium Oxalate Kidney Stones

Fahimeh Haghighatdoost, Reyhaneh Sadeghian, Cain C T Clark, Behnood Abbasi

Research output: Contribution to journalArticlepeer-review


OBJECTIVES: Diet-dependent net acid load may influence the risk of kidney stone formation by affecting calcium and citrate excretion. However, to date, little research has investigated the relationship between dietary acid load and kidney stones. Therefore, this study sought to assess whether a diet high in potential acid load was related to the risk of calcium oxalate stone formation.

METHODS: This case-control study was conducted on 430 participants (including 215 newly diagnosed patients with calcium oxalate stones and 215 controls matched for sex and age). Dietary intake was assessed using a validated food frequency questionnaire over the preceding year. Dietary acid load was estimated based on the potential renal acid load (PRAL) and net endogenous acid production (NEAP). The association between dietary acid load indices and kidney stone was examined using multivariable logistic regression.

RESULTS: Mean PRAL (standard error) was significantly lower in cases versus controls (-5.3 ± 1.3 vs. -1.7 ± 1.3, P = .048). Corresponding values for NEAP were 39.4 ± 0.8 and 41.8 ± 0.8, respectively (P = .032). After adjustment for potential confounders, the odds ratios (95% confidence intervals) of calcium oxalate stones in the top tertile of PRAL and NEAP were 1.45 (0.89-2.38, P = .136) and 1.88 (1.14-3.09, P = .013), respectively. Adjustment for potassium and protein in 2 separate models did not substantially change the results.

CONCLUSIONS: A diet high in potential acid load, measured by NEAP, was associated with higher risk of calcium oxalate stone formation, independent of potassium and protein intake. Prospective longitudinal studies are warranted to confirm the veracity of our results.

Original languageEnglish
Pages (from-to)(In-press)
Number of pages8
JournalJournal of renal nutrition : the official journal of the Council on Renal Nutrition of the National Kidney Foundation
Publication statusE-pub ahead of print - 25 Sep 2020

Bibliographical note

Copyright © 2020 National Kidney Foundation, Inc. All rights reserved.

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics
  • Nephrology

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