Sandy C. asks: I have 4 indoor cats, 1 male and 3 females ranging in age from 2 to 10. My male cat had an episode of stones in his bladder a few years ago, so since that time I have had all 4 on urinary tract related commercial foods. All 4 are growing tired of the limited flavors.

 

 

 

Sandy, those are great questions. A raw diet may be a good choice for all of your cats, with some possible tweaking for the cat with kidney problems. You might want to take a look at a recent blog that addressed a related question about crystals in urine and how a raw diet can be beneficial in addressing urinary tract issues.

 

If the urinary tract diet you were feeding your male cat was an acidified diet, it would be a good idea to keep it away from the cat with kidney problems. Acidified diets often cause excess potassium levels. This can worsen kidney function and cause other serious side effects.¹

 

The most important issue with a urinary or kidney problem is water. The best and most natural way to do that is in their food — but it needs to food they will want to eat. This is where prescription canned diets run into trouble. Cats frequently don't want to eat them. A raw diet is highly palatable and provides plenty of variety. Once transitioned, cats love raw food and eat it eagerly.

 

Consider feeding no dry food at all. A cat with a urinary or kidney disorder will have difficulty with dry food of any sort, including a prescription dry food. Cats have a low thirst drive compared to humans. They evolved in an arid environment, getting almost all water from prey. A mouse, for example, is about 65% water. Cats eating dry food run the risk of being chronically dehydrated, causing long-term stress on their urinary tract and kidneys.

 

A modified raw diet is appropriate for a cat with kidney trouble and can be a great benefit to your cat's overall health. Depending on how you and your vet decide to proceed, her diet may end up being different than that of the others. You may need to feed her separately. Her diet would be the same food as that for all of the cats, with small additions to her portion.

 

Ask your veterinarian about the food he or she recommended for your cat. Most foods formulated for kidney problems have reduced protein. This idea came from work with dogs over the past five decades.² Dogs with CRF fed a protein-restricted diet seemed to do better than on a high protein diet. This became the standard diet therapy for both cats and dogs. In more recent times its value has been questioned, particularly for cats.³ Cats have a greater dietary requirement for protein and depend upon it for their energy needs. Further, reducing protein makes the food much less palatable. A sick cat that does not eat certainly will not thrive.

 

Dietary phosphorus reduction has been shown to be beneficial for cats with CRF.⁴ Meat is high in phosphorus. When protein intake is reduced, it also lowers phosphorus intake. But, reducing essential protein to achieve phosphorus reduction is nutritionally unsound. Your vet can prescribe phosphorus binders that can be added to her food.⁴ This allows you to feed a highly palatable, high moisture and high protein raw diet.

 

Another approach is to add chopped, cooked egg white to her food. Egg whites contain no phosphorus but are high in protein, and thus dilute the phosphorus content overall. Your vet can test to see if your cat has elevated blood phosphorus levels and determine if phosphorus binders or cooked egg white should be added to her food.

 

Cats with CRF frequently develop secondary hyperparathyroidism. This happens when the kidneys become unable to balance the levels of phosphorus and calcium in the blood.  As the kidneys begin to fail, they lose the ability to activate vitamin D and to excrete excess phosphorus. As vitamin D levels decline, blood calcium also drops and blood phosphate levels rise. The parathyroid glands start releasing parathyroid hormone to activate vitamin D in an effort to keep blood calcium levels in balance with rising blood phosphorus levels. Unfortunately, failing kidneys may be unable to respond. Excess phosphorus in the blood combines with calcium to form crystals that are deposited in soft tissues such as the kidneys, which further impairs function. This removal of calcium from the blood then triggers calcium to be released from the bones, making them soft. It's a vicious cycle. Monitoring and controlling phosphorus levels are critical to stop this cycle which otherwise may cause your cat to deteriorate further.

 

Cats with secondary hyperparathyroidism but normal phosphorus levels may also benefit from small doses of calcitriol, the active form of vitamin D. This may stop or slow the overproduction of PHT. Your cat would need to be monitored closely to watch for excessive calcium in the blood.

 

Recently, ACE inhibitors developed for humans have been shown to help to stabilize cats with CRF where hypertension is common. Ace inhibitors, such as benazepril, help increase blood flow to the kidneys and reduce blood pressure. Sometimes benazepril is combined with amlodipine, a calcium channel blocker, if blood pressure is not controlled by ACE inhibitors alone. Your cat should be tested for phosphorus levels in order to know how to proceed in treatment.

 

Keep in mind that many veterinarians are not well educated about a carnivore's dietary requirements; they may be reluctant to embrace a dietary change to raw feeding because of a lack of knowledge and experience. Ask your vet to work with you on the monitoring necessary to accomplish this transition. Consider consulting a more raw-savvy vet if you have any concerns about the course of treatment your current vet suggests.

 

Please let us know how things go. A multi-cat household is always a more demanding environment when illness is present.

 

 

¹ Steven W. Dow, Martin J. Fettman, Katharine R. Smith, Dwayne W. Hamar, Larry A. Nagode, Kent R. Refsal, W. Lee Wilke, "Effects of Dietary Acidification and Potassium Depletion on Acid-Base Balance, Mineral Metabolism and Renal Function in Adult Cats," The Journal of Nutrition, January 1990

² Kenneth C. Bovée, DVM, MMedSc, "Mythology of Protein Restriction for Dogs with Reduced Renal Function," Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, 1998

³ Finco DR, Brown SA, Brown CA, Crowell WA, Sunvold G, Cooper TL, "Protein and Calorie Effects on Progression of Induced Chronic Renal Failure in Cats," American Journal of Veterinary Research, May 1998, Vol. 59, pp. 575-82

⁴ Peter Markwell, "Recent Advances in the Dietary Management of Chronic Renal Failure in Cats," World Small Animal Veterinary World Conference, 2001