Oxalate

Oxalate (oxalic acid) is a dietary compound (spinach, rhubarb, nuts, chocolate) and endogenous metabolic end-product that forms insoluble calcium oxalate crystals — the primary component of ~80% of kidney stones. The gut microbiome is the primary route of oxalate degradation via Oxalobacter formigenes and other oxalate-degrading bacteria (oxalobacter).

Microbiome Connection

  • Oxalobacter formigenes uses oxalate as its sole carbon source, directly reducing enteric oxalate absorption and urinary oxalate excretion. Loss of O. formigenes (e.g., from antibiotic exposure) increases kidney stone risk.
  • In CKD, altered gut microbiota composition affects oxalate handling [1] [2] [3].
  • Dietary fiber modulates oxalate-degrading bacteria abundance.

Cross-References

References (3)

  1. Jean A. Hall, Matthew I. Jackson, Dennis E. Jewell et al. (2020). Hall et al. 2020 — CKD in Cats Alters Response of the Plasma Metabolome and Fecal Microbiome to Dietary Fiber. PLOS ONE. doi:10.1371/journal.pone.0235480
  2. Elisabetta Margiotta, Francesco Miragoli, Maria Luisa Callegari et al. (2020). Gut Microbiota Composition and Frailty in Elderly Patients with Chronic Kidney Disease. PLOS ONE. doi:10.1371/journal.pone.0228530
  3. Wang, Li, Zhang et al. (2023). Wang 2023 — Perturbed Gut Microbiome and Metabolomes Across CKD Severity. Microbiome. doi:10.1186/s40168-022-01443-4

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