So, my cat recently underwent surgery for urinary stones. Luckily, the veterinarian caught it early and he is now doing well. I am wondering if this can be caused by diet, or lifestyle, etc. Also, what is the difference between digestive and urinary food? My cat has digestive issues, and I am wondering if urinary food will decrease his chance of getting urinary stones again and be good for digestion. Thanks!

1 Answer 1


Urinary stones in cats form due to a combination of two main factors: urine pH and urine concentration. Crystals and stones form is urine that contains high concentrations of crystallogenic substances such as magnesium, phosphate, and calcium. Common crystals are struvite (magnesium ammonium phosphate) and calcium oxalate. These common crystals and stones of concern in cats will form in alkaline urine (high pH).

As pet owners one can affect their cats urine pH and concentration with:

  • Diet: prescription urinary diets such as Hill's c/d or Royal Canin SO contain lower amounts of magnesium, phosphate, and calcium, and help keep the urine pH low. Hill's c/d also contains potassium citrate to prevent formation of calcium oxalate stones, and for this reason is usually my first choice when putting a patient on a prescription urinary diet. Gastrointestinal diets are not formulated to prevent urinary stones and are not ideal in your cat's case.
  • Water: Making sure there are plenty of water sources is important, including water fountains. Wet foods help increase water intake. More water intake means less concentrated urine, meaning less risk of crystals and stones.

There are medications that your vet may recommend to further reduce the urine pH, such as methionine (Methigel).

Often urinary stones and crystals are found in combination with urinary tract infections, because bacteria thrive in alkaline urine. Therefore, antibiotics are important in initial management of urinary calculi.

Cats who are prone to cystitis and urinary obstructions benefit from low-stress environements, using tools such as Feliway (natural cat pheremones) to manage their stress. This does not, however, directly affect whether urinary stones form.

The major concern with urinary stones is that they will pass into the urethra and cause a urinary obstruction – a life threatening emergency. It is therefore essential that cats who have a history of stones are put on an appropriate prescription urinary diet. In my opinion, diet is the number one thing you can do to prevent stones from forming again.

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