Food oxalate: factors affecting measurement, biological variation, and bioavailability

J Am Diet Assoc. 2007 Jul;107(7):1191-4; quiz 1195-6. doi: 10.1016/j.jada.2007.04.007.


Food and nutrition professionals provide medical nutrition therapy for patients with kidney stones. If the stones contain oxalate or the patient has been diagnosed with hyperoxaluria, reduction of dietary oxalate may be appropriate. Differences in oxalate values for a single food may be due to analytical methods, and/or biological variation from several sources, including cultivar, time of harvest, and growing conditions. Bioavailability of food oxalate and, thus, urine oxalate, will also be affected by salt forms of oxalate, food processing and cooking methods, meal composition, and the presence of Oxalabacter formigenes in the patient's gut. Dietary advice for reducing urinary oxalate should include both reduction of dietary oxalate and simultaneous consumption of calcium-rich food or supplement to reduce oxalate absorption.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Biological Availability
  • Calcium Oxalate / analysis
  • Calcium, Dietary / administration & dosage
  • Calcium, Dietary / pharmacology
  • Cooking / methods
  • Cooking / standards
  • Food Analysis / methods
  • Food Analysis / standards*
  • Humans
  • Intestinal Absorption
  • Kidney Calculi / diet therapy*
  • Kidney Calculi / prevention & control
  • Oxalates* / adverse effects
  • Oxalates* / analysis
  • Oxalates* / pharmacokinetics


  • Calcium, Dietary
  • Oxalates
  • Calcium Oxalate