Your Guide to Renal Food for Cats With Kidney Disease

Cat sitting in front of red bowl
A renal diet may be beneficial to cats with chronic kidney disease as it can slow the progression of the disease and enhance their quality of life.

Chronic kidney disease (CKD) is a persistent health issue that is thought to affect between 30-40% of cats over the age of ten.1 Although there’s no cure for CKD, in some cases tailored nutrition can help support cats by restricting and supplementing certain nutrients to help promote renal health.

In this article, we look at key nutrients that are important when managing CKD, how they work and what you can do to encourage your cat to eat if they’re suffering from CKD.

What is Chronic Kidney Disease?

Inside your cat’s kidneys are thousands of tiny filters called nephrons that work to remove toxins from the bloodstream and recycle beneficial substances like amino acids and minerals. 

CKD is triggered by a loss of nephron function, possibly due to a disease, an injury, or an inherited condition. Without sufficient nephron function, important substances are lost and toxins and wastes that are normally eliminated begin to accumulate in the bloodstream, which can damage kidney tissue, cause clinical signs and create progressive injury to the kidney. 

How Can I Spot the Signs of Kidney Disease?

Signs of kidney disease can include weight loss, increased thirst and urinating more frequently. 

Unfortunately, these signs are usually not clearly visible until a significant amount of kidney function has been lost. 

The early signs of CKD are subtle and the best way to monitor for the disease is to maintain regular veterinary check-ups. Some veterinarians can screen for the condition using a new predictive tool called RenalTech(TM).

 You can find out more in our two articles: Chronic Kidney Disease in Cats and The Signs of Chronic Kidney Disease in Cats.

Why Are There Specific Diets for Cats With Kidney Disease?

Nutritional management has long been a therapy of choice for cats affected with CKD. A tailored renal diet not only helps to slow the progression of the condition but can also lessen some of the disease’s effects.2 It does this by:

 

Illustration of phosphorus

Limiting phosphorus

As we explain below, phosphorus plays a major role in the speed of CKD progression and limiting a cat’s intake can prolong survival.3

Illustration of energy

Maximizing energy density

Cats with CKD will often eat less. Providing an increase in calories in smaller portions helps to maintain their weight and may help decrease weakness and lethargy. 

Illustration of muscle

Maintain body condition

Providing nutrition tailored for cats with CKD can help reduce weight loss, maintain ideal body condition and help minimize the loss of muscle mass. 

Illustration of a set of scales

Balance protein levels

Too much protein can increase the level of toxins in the bloodstream of a cat with CKD, but too little can cause a reduction in muscle mass. Your veterinarian will recommend a diet with a balance of protein which may help improve your cat's quality of life.

Illustration of intestines

Digestive Support

Gastrointestinal upset is common in cats with CKD, but providing a balance of small amounts of fiber can offer some support.

Which Nutrients Are Important for a Cat With Kidney Disease?

There are several key nutrients that are especially important for cats with CKD:

Illustration of protein

Protein

Healthy cats require a lot of protein in their diet. Unfortunately, many of the toxins that build up within the bloodstream during CKD are caused by the body breaking down protein. Veterinarians can recommend specific diets that have restricted amounts of protein, which can help reduce the accumulation of harmful waste products. Renal diets are very carefully balanced and use high-quality sources of protein, as too little protein can result in muscle wasting and other complications. 

Illustration of phosphorus

Phosphorus

This essential mineral is found in many foods and is a component of bones and teeth. Normally a cat will excrete excess phosphorus in urine, but cats with CKD are unable to do so, which results in a gradual increase in phosphorus and calcium levels. Restricting phosphorus may be beneficial to the life expectancy of cats with CKD.3

Illustration of potassium

Potassium

This electrolyte is vital to the function of muscles and nerves. As kidney function is lost, a cat may experience a loss of potassium (hypokalemia) which causes muscle weakness. Renal diets typically contain higher levels of potassium for this reason, although supplements may still be recommended by your veterinarian if levels drop too low. 

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B Vitamins

Cats with CKD lose the ability to concentrate their urine and so they drink and urinate more frequently. This can lead to a loss of water-soluble vitamins, including various B vitamins. Renal diets will typically help to compensate for this. 

Illustration of omega 3

Omega-3 fatty acids

Some studies have shown that EPA and DHA found in fish oils may help to reduce inflammation and decrease the amount of protein in the urine of cats with CKD. 

 

When Should I Start Feeding My Cat a Renal Diet?

A veterinarian will typically recommend a renal diet as soon as your cat has been diagnosed with CKD. 

However, the renal diet they suggest will depend upon the stage of CKD, which progresses from IRIS Stage 1 to 4 based on the amount of kidney function that has been lost.

What Types of Renal Diet are There?

If your cat is diagnosed with IRIS Stage 2 CKD onwards, phosphorus will need to be restricted and a lower protein diet with a high energy density such as Royal Canin Renal Support is often recommended. 

At this point, the accumulated toxins inside the cat’s bloodstream may begin to affect appetite. Renal diets are designed to be very palatable and some, like Royal Canin’s, can be mixed as dry and wet food to combine aromas, shapes, sizes and textures that encourage eating. 

Gentle warming of wet diets and adding warm water to dry diets can also help cats stay interested in their food. A cat with CKD will need access to lots of fresh water. Water bowls should be placed in a separate area to where they’re fed. 

Some cats with CKD may also have food sensitivities and may benefit from a renal diet that includes highly digestible hydrolyzed protein

In the final stages of CKD, a veterinarian may use a liquid diet if specific types of feeding tubes are placed.

A tailored veterinary diet may help improve the quality of life of cats with CKD. If you have any questions or concerns about nutrition and CKD, speak to your veterinarian.

References:


1 Polzin DJ. Chronic kidney disease. In Bartges J, Polzin DJ, editors. Nephrology and urology of small animals. Ames (IA): Wiley- Blackwell, 2011: 433-471.

2 Polzin DJ. Evidence-based step-wise approach to managing chronic kidney disease in dogs and cats. J Vet Emerg Crit Care 2013;23(2):205-215.

3 King JN, Tasker S, Gunn-Moore DA, et al. Prognostic factors in cats with chronic kidney disease. J Vet Intern Med 2007;21:906-916

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