J. Veronika Kiklevich, DVM
Q. What do you advise on urine acidifying diets? I read that they can cause formation of calcium oxalate bladder stones. My 17-year-old male cat is on a urine-acidifying diet, and I also have a 2-year-old cat and a new kitten. My vet has told me that it is OK to feed this food to all of the cats. Is this a safe recommendation?
A. While it is true that diets that acidify the urine can promote the formation of calcium oxalate kidney and bladder stone, most of the major brand name acidifying diets actually keep the pH of the urine in a very narrow (optimal) range that does not favor the formation of either struvite or calcium oxalate. To keep the urine in this very narrow range, it is highly recommended not to feed your cat any other food or treats along with the diet. In a sensitive cat, even the occasional treat can disrupt the urine pH to the point where stones can form.
Keeping the urine dilute is also important, so using canned food and encouraging water consumption is vital in diminishing stone formation. To be certain that your cats' urine pH is in an appropriate range, have them tested after keeping them on a strict diet for two weeks.