Raw spinach is high in oxalate which can contribute to the formation of kidney stones, particularly calcium oxalate stones.[1][3][4]
– Spinach contains higher concentrations of oxalate than most crops, and consuming a normal portion (50-100g) of raw spinach can result in a significant increase in urinary oxalate excretion.[1][3] This heightened oxalate load increases the risk of calcium oxalate kidney stone formation.
– Food frequency questionnaire studies have identified raw and cooked spinach as a major dietary source of oxalate in kidney stone-forming populations, despite its infrequent consumption.[3] This suggests that even sporadic intake of high-oxalate foods like spinach can contribute to stone risk.
– To reduce kidney stone risk, experts recommend limiting intake of high-oxalate foods like spinach, rhubarb, nuts, and certain berries for those prone to calcium oxalate stones.[4][5]
– Consuming calcium-rich foods like dairy products along with oxalate-rich meals can help bind oxalate in the gut and reduce its absorption.[3][4]
In summary, the high oxalate content of raw spinach is clearly associated with an increased risk of calcium oxalate kidney stone formation, especially with frequent or excessive consumption.[1][3][4][5] Moderation of raw spinach intake is advisable for individuals susceptible to this type of kidney stone.
Citations:
[1] https://enewsletters.k-state.edu/youaskedit/2017/08/15/spinach-and-kidney-stones/
[2] https://www.webmd.com/kidney-stones/kidney-stones-food-causes
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6459305/
[4] https://www.health.harvard.edu/blog/5-steps-for-preventing-kidney-stones-201310046721
[5] https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-minute-what-you-can-eat-to-help-avoid-getting-kidney-stones/