Dry food is convenient, affordable, and easy to measure. It is also, for many cats fed exclusively on it, a slow-motion kidney problem waiting to develop.
Chronic kidney disease (CKD) is the leading cause of death in older cats in the UK.1 It is not caused solely by dry food — genetics, age, and other factors play a role. But the relationship between low dietary moisture and feline kidney health is well established in veterinary literature, and it is one of the clearest cases where diet makes a measurable long-term difference.
Why struvite crystals form — and what causes them
Struvite crystals are mineral deposits that form in concentrated urine — the kind produced by cats who are not absorbing enough water.3 They can cause painful urination, blockages, and in male cats especially, life-threatening urinary tract obstructions. Feline Lower Urinary Tract Disease (FLUTD) encompasses several of these conditions and is disproportionately common in cats fed dry-only diets.
A high-protein, low-carbohydrate diet naturally produces less concentrated urine. Wet food, for the same reason, is one of the most consistently recommended dietary changes by vets managing urinary conditions.
What you can do now, practically
- Switch the primary meal to wet food, even if you retain dry as a supplement or treat.
- If your cat prefers dry, try adding warm water or low-sodium broth to increase moisture intake.
- Use a pet water fountain — running water demonstrably increases feline drinking behaviour.4
- Place water bowls in multiple locations, away from the food bowl.
- If your cat is over seven, ask your vet about annual kidney function blood tests. Early detection changes outcomes significantly.