Does the food differ for struvite versus oxalate crystals?

Yes, radically. Struvite dissolves with an acidifying, diluting diet that restricts magnesium and phosphorus. Calcium oxalate does not dissolve and calls for less acidic, dilute urine to prevent recurrence. Acidifying an oxalate-prone cat can harm it. Hence the need to identify the crystal before choosing the food (Merck Veterinary Manual). Expert deep dive ### How do the two strategies oppose each other? Struvite needs acidic urine to dissolve and stop reforming, with restriction of the magnesium and phosphorus that make it up. Oxalate forms in acidic urine: its prevention aims instead for less acidic, more neutral, dilute urine. The two pH goals are therefore opposite (Today's Veterinary Practice). A single universal "anti-crystal" diet does not exist: pH targeting is specific to the mineral. ### Why is mistargeting risky? Crucial, counter-intuitive fact: acidifying the urine to treat struvite favours oxalate formation in a predisposed animal. A mistargeted regimen can therefore convert a struvite problem into an oxalate problem, harder to manage because it is not dissolvable. That is exactly why crystal analysis precedes any dietary choice (Merck Veterinary Manual; Today's Veterinary Practice). Diluting the urine, by contrast, helps in both cases and forms the common foundation. Comparison table | Parameter | Struvite | Calcium oxalate | |---|---|---| | Target urine pH | acidic | less acidic, more neutral | | Restricted minerals | magnesium, phosphorus | moderate dietary calcium and oxalate | | Dietary dissolution | possible | impossible | | Risk of mistargeting | favour oxalate | favour struvite | Petipedia's take Petipedia warns against the idea of one universal urinary food, stressing that struvite and oxalate demand opposite pH strategies validated by the vet.