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 hall 2020 ckd cats dietary fiber metabolome microbiome margiotta 2020 gut microbiota frailty elderly ckd wang 2023 perturbed microbiome metabolomes ckd severity.
- Dietary fiber modulates oxalate-degrading bacteria abundance.
Cross-References
- oxalobacter — primary oxalate-degrading organism
- chronic kidney disease — oxalate handling impairment
- calcium — calcium oxalate crystal formation