what is a kidney diet for cats

Kidney Diets for Cats: What to Look for

By Jennifer Coates, DVM

Kidney disease is extremely common in cats. It can develop quickly, because of something like an infection or exposure to antifreeze, or over many years for no apparent reason. Symptoms and treatment for kidney disease vary depending the specifics of the case, but oftentimes, a diet change can help.

Why Diet Matters

The kidneys have many roles in the body. Two of these major roles include removing waste products from the bloodstream and conserving water. When kidney function declines past a certain point, toxic waste products like urea and phosphorous begin to back up within the body, which can make a cat feel terrible. Poor kidney function also leads to dehydration because more water than normal is lost in the urine.

Both of these problems can be at least partially addressed with diet. Foods that have a high water content can help prevent dehydration, and when cats eat a diet made from moderate amounts of high quality protein, they produce less urea and phosphorous that then needs to be eliminated.

Over-the-Counter Foods

Cats who are in the early stages of kidney disease often thrive when fed an appropriate, over-the-counter food. Canned foods are best because they contain much more water than dry foods, but you still need to make sure the diet is made from high-quality ingredients.

Look for animal-based protein sources (chicken, beef, salmon, etc.) that sound like something you might eat rather than a byproduct of a manufacturing process. If your cat simply will not eat canned food, choose a dry food that is made from high-quality ingredients and do everything you can to encourage your cat to drink a lot of water. If your cat eats dry food, you may need to start giving subcutaneous fluids (fluids injected under the skin) sooner than you would otherwise.

Determining the right protein level for your cats food is tricky. Too much protein will increase the amount of urea and phosphorous the body needs to get rid of. On the other hand, cats with chronic kidney disease often suffer from muscle wasting, and too little protein can make this problem worse. Your veterinarian is the best person to make a recommendation regarding an appropriate dietary protein level for your cat.

Prescription Foods

Cats with more advanced cases of kidney disease can benefit from eating a prescription food. Prescription kidney diets tend to provide a moderate level of protein but are quite low in phosphorous, which helps keep the production of waste products as low as possible. These foods also usually have a reduced sodium content to prevent dehydration, are high in specific amino acids to promote muscle mass and contain other ingredients, like omega-3 fatty acids, that support kidney health.

Prescription kidney diets are available in canned and dry formulations, but once again, canned is usually best because of its high water content. The biggest problem with these foods is that cats will sometimes refuse to eat them. Manufacturers have worked hard to make their products tastier than they used to be, but you may still need to try several before you find one that your cat will relish.

Homemade and Raw Foods

When a cat is not eating enough to maintain a healthy weight, that particular food is failing to meet his or her nutritional needs even if it looks like it should be a good choice. The solution may be as simple as trying a different brand of prescription kidney diet or over-the-counter food, but if youre willing to cook for your cat, a homemade diet might also be a good option. Homemade foods are usually so tasty that they will improve almost any cats appetite.

However, homemade diets can also be dangerous. Studies have shown that the majority of homemade pet diets are nutritionally incomplete, and this is especially true for the kidney disease recipes that you can find online or in books. Raw diets can also be risky for sick cats because their immune systems are not as strong as they once were and uncooked meat in particular can expose cats to potentially dangerous food-borne pathogens.

Before feeding your cat a raw or home cooked diet, talk to your veterinarian and/or a veterinary nutritionist who can put together a safe and nutritious recipe that will meet all of your cats needs.

Your Guide to Renal Food for Cats With Kidney Disease

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 theres 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 theyre suffering from CKD.

What is Chronic Kidney Disease?

Inside your cats 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 Catsand 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 diseases effects.² It does this by:

Whats the Best Food for Cats With Kidney Disease?

Dietary management cant turn back the clock on kidney disease, but it can make the future brighter. Feeding your cat the right food is the best way to slow the diseases progression, minimize symptoms, and give your cat the best life possible.

We recommendRoyal Canin Veterinary Diet Renal Support D Morsels in Gravyas the overall best cat food for kidney disease because its low in phosphorus with controlled sodium, added B vitamins, and anti-inflammatory omega-3s. No diet is perfect, but this product has a strong reputation for helping cats with chronic kidney disease (CKD).

At a Glance: Best Food To Buy for Cats With Kidney Disease

Overall Best

10.0

Picked by 31 people today!

• Maximized energy density to help keep cats strong and muscular
• Contains omega-3 fatty acids to reduce inflammation
• Low phosphorus levels help your cat to feel better

Runner Up

9.8

Picked by 31 people today!

• Controlled phosphorus levels
• Added omega-3 fatty acids for anti-inflammatory effect
• Calorie-dense to support muscle mass

Best Non-Prescription

9.8

Picked by 18 people today!

• Contains more than 50% protein on a dry matter basis
• Made with lean animal-based protein from chicken and egg white
• Contains up to 50% less phosphorus than AAFCO minimums

Best Budget

9.7

Picked by 18 people today!

• Top three ingredients are animal-based
• Rich in hydrating moisture to support renal function
• Made with a single source of animal protein

Best Prescription Raw Food

9.6

Picked by 21 people today!

• Restricted phosphorus content
• Added omega-3 fatty acids
• Elevated levels of B-complex vitamins

Best Prescription Dry Cat Food

9.5

Picked by 18 people today!

• Omega-3 fatty acids from fish oil help reduce inflammation
• Controlled phosphorus helps your cat feel healthier
• Customers report that the square kibble is easy for their senior cats to eat

Best for Early Stages

9.4

Picked by 31 people today!

• Low in phosphorus, which might help to prevent and ease the symptoms of kidney disease
• Rich in easily-utilized animal protein
• Low carbohydrate content

Best for Advanced Stages

9.4

Picked by 25 people today!

• Low in phosphorus
• Highly palatable
• Calorie dense to support lean body mass

Why Trust Cats.com

Before selecting products for testing, we dug deep into the subject of dietary management of kidney disease in cats. We reviewed scientific studies, vet interviews, and other resources to determine what qualities make a cat food product appropriate for cats with kidney disease. Finally, we consulted our own panel of veterinary experts for advice.

With this expert guidance, we selected a handful of products for in-depth evaluation. We spent hours analyzing labels, reading customer reviews, and communicating with the manufacturer directly to determine each products dry matter phosphorus content. The products featured here were purchased at full retail price and personally tested by members of our team with their own cats at home.

Chronic Kidney Disease in Cats Explained

This article is not a substitute for veterinary advice. Your veterinarian can provide personalized suggestions relevant to your cats unique situation.

What To Look For in Cat Food for Kidney Disease

Years of scientific research and experience have left cat owners, seasoned veterinarians, and scientists with more questions than answers regarding chronic kidney disease (CKD).

This article cant give you all the answers to the feline CKD puzzle, but it will help you understand the complex dynamics between diet and disease. You should walk away from this article feeling less overwhelmed and more confident about your ability to make the right choices for your cat.

Youll find out why food matters, learn what goes into a great diet, and read reviews of the best foods for cats with kidney disease. Lets start with the key principles of feeding a cat with CKD.

Monitoring the progression of your cats kidney disease is essential, even if you make dietary changes. Kidney-Chek, an at-home saliva test, can help you keep tabs on your cats kidney function. Learn more about Kidney-Chek here.

Protein and CKD

When dietary protein breaks down during digestion, it produces waste. One of these waste products is urea. Healthy kidneys filter out this waste and send it on its way into the litter box.

But as your cat loses kidney function, it becomes increasingly difficult to remove these waste products. Instead of passing through your cats body, waste products remain in the bloodstream. This is why blood urea nitrogen (BUN) levels rise in cats with CKD. BUN is a measurement that veterinarians analyze on routine bloodwork to evaluate kidney health.

In an attempt to reduce BUN levels, cats with CKD are often given protein-restricted foods. But in recent years, this practice has becomeincreasingly controversial.

Experts worrythat a protein-restricted diet will lead to severe protein deprivation, decreased muscle mass, and poor physical condition. Instead of cutting back to 20% or fewer calories from protein, you might choose to feed moderate levels of highly digestible, low-waste protein from high-quality animal sources.

The bottom line is that you want your cat to feel better, not worse. Although a protein-restricted diet helps some cats feel better, it might also lead to muscle wasting and weakness. Talk to your veterinarian about the costs and benefits of a low-protein diet for your cat.

Phosphorus Content Less Than 0.5%

As kidney function declines, phosphorus is one of the things that doesnt get filtered out. As phosphorus builds up in the bloodstream, your cat will start to feel ill and kidney function declines even more quickly.

The best way to counteract this effect is to reduce the amount of phosphorus in your cats diet. The ideal diet for a cat with CKD contains less than 0.5% phosphorus on a dry matter basis.

Relatively Low Sodium Content

Because excessive sodium consumption can increase blood pressure and worsen kidney damage, most renal (kidney) diets are low in sodium. Youll also want to avoid any high-sodium treats like lunch meat and salty cheese.

Anti-Inflammatory Omega-3 Fatty Acids

Many cats with kidney disease develop nephritis, which is inflammation of the kidneys. Along with other anti-inflammatory supplements, consider omega-3 fatty acids like EPA and DHA. These fatty acids have a well-documented ability to reduce inflammation, helping your cat to feel better.

Although humans and other animals can benefit from omega-3 fatty acids derived from plant sources like flaxseed oil, cats can only utilize those found in animal fat. Good sources include various types of fish oillike salmon oil, menhaden fish oil, and sardine oilas well as krill oil. You can also consider green-lipped mussels. In addition to being a good source of other omega-3s, theyre the oceans most concentrated source of the fatty acid EPA.

Although many foods contain sources of these beneficial fatty acids, you might also want to supplement your cats diet with agood omega-3 supplement.

Supplementation With B Vitamins

Because cats with kidney disease urinate so much, they often lose crucial B vitamins in the litter box. Deficiency in B vitamins is associated with loss of appetite and overall poor health.

Prescription or therapeutic diets for kidney disease are usually fortified with additional B-complex vitamins. Your veterinarian might also recommend B12 shots to give your cat a boost.

In addition to vitamins in your cats diet and subcutaneous injections, consider giving your cat a multivitamin supplement likeVetoquinol Renal K+. Formulated for cats and dogs with kidney disease, this gel contains B-complex vitamins and potassium. Both substances support muscle function and your cats nervous system health.

High Moisture Content

Kidney disease causes cats to urinate excessively and lose their appetites, so dehydration is common among cats with the condition. Many cats rely on subcutaneous fluid injections (injections under the skin) to stay hydrated, but theres more than one way to increase your cats water intake.

Wet food is 70% water or more, making it an effortless source of the hydration your cat needs. If youre currently feeding a dry diet, switching to wet food might give your cat an additional four ounces of water each day. Thats as much or more than theyd get in a typical fluid injection.

Your cat might still need additional subcutaneous fluids, but feeding a juicy diet will significantly reduce your cats risk of severe dehydration.

Should You Feed Your Cat Prescription Food for Kidney Disease?

Currently, prescription or therapeutic diets are the only foods that check all the boxes from the previous section.

Frustratingly, those diets often have other not-so-great qualities like high carbohydrate content, added sugar, and potentially low-quality animal by-products.

You can hold your nose over the ugly parts of a therapeutic or prescription diet. You can opt for non-prescription food that meets one or two of the above criteria. Or you can make CKD-appropriate food at home.

By doing it yourself, you can provide the nutrition your CKD cat needs while being able to choose the types of ingredients you prefer. But youre also taking a riskhomemade food takes time to prepare, and it can be hard to get everything right. If youre going to make homemade cat food for kidney disease, always work with a veterinary nutritionist or your veterinarian to ensure the recipe is appropriate.

For more information, check out ourguide to creating a raw diet for your cat with kidney disease.

The 8 Best Foods for Cats With Kidney Disease

Prescription or therapeutic diets earn the top spots on our list of recommendations because they offer a combination of renal disease-appropriate qualities that you wont find in any other commercial food.

If prescription food isnt within your budgetor if your cat is in the early stages of kidney diseasea non-prescription product might suit your needs. Youll find several options on this list.

Above All, Cats With Chronic Kidney Disease Need To Eat

From Dr. David J. Polzin, DVM, Ph.D., DACVIMs 11 Guidelines for Conservatively Treating Chronic Kidney Disease:In many or most dogs and cats with chronic kidney disease, death or euthanasia results directly or indirectly from starvation.

The dietary recommendations above apply only to cats that are still eating. But if the disease has progressed to a point where your cat is no longer interested in food, nutritional rules go out of the window. If your cat is refusing to eat, dont worry about feeding a therapeutic diet. Any food theyre willing to eat is good food.

Consider Giving Your Cat High-Calorie Supplements

In addition to traditional food, talk to your veterinarian about giving your cat high-calorie supplements. High-calorie gels and treats help to curb weight loss and keep your cat feeling as well as possible. Consider nutritional gels likeTomlyn Nutri-CaandVetoquinol Nutri-Cal.

Food toppers, broths, and treats can also help. Some cats, especially those with poor dental health, might be willing to eat baby food.

You Might Also Consider Supplementing Your Cats Diet With a Probiotic

When bacteria and endotoxins enter the gut, probiotics might help to perform enteric dialysis, taking on some of the detoxifying function that the kidneys have lost.

Azodylis a synergized prebiotic and probiotic supplement designed for cats with kidney disease. The supplement contains patented strains of Enterococcus thermophilus, Bifidobacterium longum, and Lactobacillus acidophilus. The three probiotics are synergized with psyllium husk, a source of prebiotic fiber.

While its not clear that Azodyl will help, it does show some promise. If youre not willing to spend more than $70 a bottle for the putative benefits of Azodyl, consider supplementing with another probiotic.

Talk to your veterinarian before giving your cat any supplements, including probiotics. Your vet can help you determine which supplements could help your cat and instruct you on how to give them.

Read Our Guide To The Best Probiotics On The Market

Here Are a Few Additional Resources To Help You Out

These resources might help you learn more about feline kidney disease and decide which foods are right for your cat.

Also known as Tanyas Comprehensive Guide to Feline Chronic Kidney Disease, this site is an extraordinary free resource for pet owners. Though not written by a veterinarian, the sites informative content has been endorsed by vets and veterinary specialists. The massive site contains more than 1,000 pages of information and covers almost everything you need to know about this disease and its treatment.

If you prefer, you can alsobuy the paperbackversion of the site. The 630-page book is available on Amazon at around $39.99.

Cat Food Database

As your cats kidney disease progresses, youll probably have to pry out their appetite with a variety of foods. The following databases might help you to evaluate your options based on CKD-relevant metrics.

Click here to browse FelineCRF.orgs food databases of dry and canned products sold in the US and UK.

An Interview with Dr. Lisa Pierson

In this 34-minute interview, well-known veterinarians Dr. Karen Becker and Dr. Lisa Pierson explore the causes and treatment of kidney disease in cats. Piersons common-sense approach is a calm in the storm of confusion that is CKD.

Frequently Asked Questions

What foods are good for cats with kidney disease?

Cats with chronic kidney disease (CKD) benefit from foods that have controlled levels of protein, and are low in phosphorus and sodium. B-complex vitamins can help to break down nutrients to help your cat feel better, and omega-3 fatty acids have an anti-inflammatory effect, which can help cats with kidney disease. A high-moisture food (a wet food) is best to provide hydration cats with kidney disease need.

How can I slow down my cats kidney failure?

Dietary modificationfeeding a diet thats helpful for cats with chronic kidney diseasecan help slow disease progression. Cats with kidney disease also need support resolving or preventing dehydration, often via subcutaneous fluid administration. Your veterinarian might also recommend certain supplements or medications to support your cats individual health needs.

What not to feed a cat with kidney disease?

Cats with kidney disease should not eat foods that are high in phosphorous or sodium. High-protein diets are also not good for cats with kidney disease. Protein should be controlled so that it is not too low and not too high. A canned wet diet is preferably to a dry diet to help keep your cat hydrated. Talk to your veterinarian about the most appropriate diet to feed your cat with kidney disease.

What makes kidney disease worse in cats?

Inappropriate diet, excessive levels of salt or phosphates, dehydration, low potassium levels, hypertension, and anemia can make kidney disease worse.