Tanya's Comprehensive Guide to Feline Chronic Kidney Disease - Which Foods to Feed, and Which to Avoid

Diet can be a useful way of controlling CKD and helping your cat to cope better with the disease. This page discusses which foods to feed. It contains information on prescription kidney diets, including what to do if your cat refuses to eat the prescription diet which your vet recommends.
It also discusses other food options, i.e. non-prescription commercial cat foods and homemade foods, and what to feed if your cat has another health problem with particular dietary requirements.
There is also information on certain foods which are not suitable for cats.
Please also read the Nutritional Requirements for more information on feline nutritional needs generally.

The Best Food for a CKD Cat... Back to Page Index

...is a food that the cat will eat. I'm not trying to be flippant here. You can source the most expensive, organic, wholesome food on the planet, but if your cat would rather starve than eat it, it is of no use whatsoever.

It is not only I who thinks it is more important that a cat eats than that a cat eats certain foods. In Nutritional management of renal disease (2008) Presentation to the World Small Animal Veterinary Association World Congress Dr K Sturgess says "It is vital that the cat eats something, as body protein catabolism will have more serious adverse effect on CRD than almost any diet."

In 11 guidelines for conservatively treating chronic kidney disease (2007) Polzin D, Veterinary Medicine December 2007, Dr Polzin makes the shocking observation that "in many or most dogs and cats with chronic kidney disease, death or euthanasia results directly or indirectly from starvation."

Are you going to let your cat starve to death? I doubt it! So please read below about the best food choices and try to feed them, but if your cat refuses to eat them, alternatives are discussed too. Bottom line, your cat is going to eat!

Food Choices and Controversies Back to Page Index

There is an amazing variety of opinions on what is the best food for healthy cats, and many of those opinions are strongly held. I sometimes get e-mails reproaching me for not advocating feeding x, y or z food. I've been told I'm condemning cats to death for not insisting my readers feed raw. Apparently even looking at a food containing by-products means I am heading for eternal damnation. I get referred to various websites, all of which I'm already familiar with, and none of which, whilst they may have some good points, convinces me that they have discovered the Holy Grail of feline nutrition.

It all reminds me of some kind of fundamentalist religion. My way good, your way bad. Please! We're talking cat food here, not the meaning of life. There are not that many studies into feline nutritional requirements, so many of the claims out there are simply personal opinion and prejudices. People love certain manufacturers. They hate others. Big names are suspect. Small firms are great. This despite the fact that both types of manufacturers may have their food manufactured in the exact same factory, by the exact same methods, using the exact same people and machinery and even in some cases the exact same ingredients, as came to light during the 2007 US food recall scandal.

Remember, if there were one perfect food for healthy cats out there, we'd all be feeding it, and all the manufacturers who didn't make it would go bankrupt. But there is no such food, so we must just do the best we can.

This website focuses on the nutritional needs of CKD cats. You may need to put your preferences for a "good food" aside and accept that quite often with a CKD cat, just getting any food in is good, getting him/her to eat a food appropriate for the CKD is an achievement, and that feeding foods you think are "good" is a bonus.

I've had three CKD cats. I know the stress and guilt of the diagnosis - and no, you didn't cause the CKD by the foods you chose to feed to your cat. I also know the stress and worry of trying to get food into a CKD cat. I'm not going to give you a guilt trip on top of that. If manufacturer A is apparently loathed but makes a food my cat loves, that's good enough for me. My cat doesn't care. She doesn't do marketing and hype. She just eats. And when she eats, I feel very relieved, and very happy.

What to Look For in a Food Back to Page Index

When it comes to food, here is what I recommend for CKD cats:

Feed a food your cat will eat! Even at the best of times, cats eat to live rather than live to eat. If you only provide a food your cat doesn't like, s/he will not eat it, especially if s/he is feeling poorly. Getting food into your cat is more important than letting him/her starve to death for your principles or because your cat is "only supposed to eat the prescription diet".

The need for a low protein food is much debated, at least in the early stages of CKD (IRIS Stage 1 and early Stage 2). You do want to feed a food that is high quality protein (which doesn't actually mean what you probably think it means).
Prescription kidney diets are not only about low protein. I would consider feeding one if my cat would eat it.
What is essential is to feed a food as low in phosphorus as you can. High phosphorus levels will make your cat feel bad and will make the CKD progress faster. Because this is so important, I've created tables of commercial foods in order of phosphorus content for the UK and US markets.

Ideally feed a wet food, because this helps with problems such as dehydration. If your cat is a dry food junkie, you may be able to gradually switch him or her over to wet food. If you can't, don't sweat it. It's more important that your cat eats than that s/he eats a wet food.

I don't like complicated cat foods. I'm not a fan of all those foods containing yummy fruits and vegetables. They are marketed to appeal to you, but your obligate carnivore feline doesn't need them from a nutritional perspective. But if they are the only foods your cat likes, don't stress over it.

I can't get too excited about "bad" ingredients. Who decides what is bad anyway? The Cat Food Police? There are certainly some ingredients I consider complete no-nos, such as onion and garlic, but that is for valid medical reasons (see below). Most of the other stuff, quite frankly, is a matter of personal choice. If I had a choice of feeding my cat a food she loved that contained by-products, for example, or letting her starve to death, the by-products would win every time.

So remember your new mantra: my cat must eat!

Prescription Foods Back to Page Index

Most vets will initially recommend that you feed a prescription food, and there are valid reasons for this. This section discusses the various prescription diets that are available, how they can help your cat, how to introduce these foods, and what to do if your cat won't eat them. It also explains why usually you should not feed prescription renal foods exclusively to other family cats.

Prescription diet choices
- Prescription food brands: USA
- Prescription food brands: UK
The benefits of prescription foods
Introducing prescription foods
When a cat refuses to eat prescription foods
Feeding prescription foods to other family cats

Prescription Diet Choices

Several manufacturers make prescription renal diets, as follows:

US Prescription Diets

There are five brands available in the USA:

Royal Canin Veterinary Diet Feline Renal LP or LP21.
Hill's k/d with chicken. Hill's also makes a g/d diet, designed for early stage CKD when numbers are hardly elevated.
Iams (formerly Eukanuba) Multi-Stage Renal Formula.
Purina NF Feline Formula.
Hi-Tor Neo. This food is available without a prescription, and is relatively high in fat content, which might be helpful in a cat who is getting too thin;

See Obtaining Supplies Cheaply for online suppliers in the USA and Canada at reduced prices.

Ohio State University Nutrition Support Service compares the various prescription diets available in the USA. Click on Search, choose Cat as the species and Reduced Phosphorus/Protein as the food type.

Prescription Diets provides an overview of the prescription diets available for various conditions.

At Pet Food Direct you can check the composition of many cat foods, both prescription and non-prescription.

UK Prescription Diets

There are six brands available in the UK:

Hills k/d. Hill's also makes a g/d diet, designed for early stage CKD when numbers are hardly elevated;
Royal Canin Diet Feline Renal Support or Royal Canin Diet Feline Renal Support S/O;

Purina PVD NF;

Eukanuba Renal Formula;

Specific Kidney Support; and

Animonda's Integra Renal Protect. This food has an extremely high Vitamin A content (a 100g tin contains the complete Vitamin A requirement for one day) so it is difficult to use it if anything else is being fed at the same time.

See Obtaining Supplies Cheaply for online suppliers in the UK at reduced prices.

The Benefits of Prescription Foods

CKD prescription diets are intended to help cats cope better with the CKD and ideally prolong their lives. Everybody knows that these foods are low in protein, but there is more to them than that. These foods differ from other cat foods in that they:

are relatively low in protein but the protein they contain is high quality protein;
are relatively low in phosphorus;
have added potasssium. This is usually in the form of potassium citrate because this can help with metabolic acidosis;
are lower in sodium;
contain higher levels of B vitamins;
contain increased levels of essential fatty acids
usually contain additional fibre.

You can read about all of these dietary components and why they are important to CKD cats on the Nutritional Requirements page.

Staged management of chronic kidney disease in dogs and cats (2009) Polzin D, Presentation to the World Small Animal Veterinary Association World Congress says "A common misconception is that renal diets are simply “low protein diets.” Renal diets encompass a variety of modifications beyond just a limitation of protein content, and, indeed, the principal beneficial effects of these diets may not accrue from their protein content. Thus, simply replacing a renal diet with a standard manufactured diet that is lower in protein content does not meet the guideline of feeding a renal diet. Since inappropriate diets can exacerbate clinical signs of uremia and/or promote progression of CKD, cats and dogs with CKD should be fed a renal diet."

Studies indicate that renal prescription diets do appear to slow the progression of renal disease, reduce the incidence of crises (which usually incorporate vomiting and appetite loss and which in the worst case may manifest themselves as crashing), and even extend life. In The kidney patient: what's for dinner? (2010) A Presentation to the World Small Animal Veterinary Association World Congress, Dr T Francey states "The administration of a renal diet to dogs and cats with CKD stages 2 and 3 markedly prolonged their renal and overall survival, it decreased the rate of decline of renal function, and it delayed the onset of uremic crises. These findings, although they don't answer the central question of the mechanism of protection, clearly show the value and the benefit of early dietary intervention in animals with CKD. In summary, we now know that dogs and cats with CKD stages 2 and 3 benefit from receiving a renal diet, but we do not know: 1) whether earlier intervention would be more beneficial; 2) whether all renal diets are equal in efficacy; and 3) what in the renal diet is truly beneficial."

The study to which many other researchers are referring when they recommend the feeding of a renal prescription diet is Clinical evaluation of dietary modification for treatment of spontaneous chronic kidney disease in cats (2006) Ross SJ, Osborne CA, Kirk CA, Lowry SR, Koehler LA, Polzin DJ Journal of the American Veterinary Medical Association 229(6) pp949-57. This study found that feeding a prescription kidney diet helped to keep BUN levels lower and appeared to help prevent metabolic acidosis in cats with more advanced CKD. The study concluded "The renal diet evaluated in this study [Hill's k/d] was superior to an adult maintenance diet in minimizing uremic episodes and renal-related deaths in cats with spontaneous stage 2 or 3 CKD." By Stages 2 and 3, they are referring to cats with creatinine between 2.1 and 4.5 mg/dl. In this two year study, 22% (five) of the cats eating a normal food died, but none died in the group eating a prescription kidney diet. The prescription foods used had 28% protein and 0.5% phosphorus on a DMA basis, while the non-prescription foods contained 46% protein and 0.9-1.0% phosphorus on a DMA basis. However, interestingly, there was no difference in parathyroid hormone levels between the two groups of cats. Also, this study did not include the use of phosphorus binders in either group of cats, which might well have made a difference, particularly to the cats eating the non-prescription diet.

If your cat is prepared to eat a prescription diet, I would feed it. Your cat is no longer healthy and has special needs which can be met by these foods. I know these diets are not considered to be "premium" or "quality" foods by many people, but the cat food manufacturers invest large amounts of money into formulating these prescription diets, and they do meet their goals (see below).

I know some people are concerned about the relatively low protein content of these foods but these foods have other attributes other than low protein. See Nutritional Requirements for an overview of the protein issue, and if you are concerned about weight and muscle loss, see Persuading Your Cat to Eat for ways to get additional nourishment into your cat.

It is better to get your cat used to prescription foods while his/her appetite is still relatively healthy, rather than trying to effect a switch at a time when your cat feels under the weather. If your cat is diagnosed following a crisis and is still under the weather, do not rush to introduce any new food - the cat may associate feeling sick with the food and refuse to eat it, ever; whereas if you had waited until the cat felt a little better, you might have been more successful. In 11 guidelines for conservatively treating chronic kidney disease (2007) Polzin D, Veterinary Medicine December 2007, Dr Polzin says "Force-feeding new diets, exposing patients to new diets while hospitalized, or administering medications or other unpleasant events during and around feeding times should all be avoided. A renal diet should be introduced to patients gradually."

With any new food, prescription or otherwise, it is also better not to introduce it too quickly because doing so may cause tummy upsets, see below.

If your cat refuses to eat a prescription food, consider trying another brand - there are a number available, as explained above.

Cornell University College of Veterinary Medicine has a short video with information on the composition of prescription diets.

Diet considerations in pets with kidney disease (2008) is a video presentation by Dr CL Langston.

Introducing Prescription Food

These foods can be rather dry (even the canned food varieties), so it is best not to try to introduce them into your cat's diet in one fell swoop. In fact, it is better for cats not to introduce any food too quickly, firstly because they are creatures of habit when it comes to food - see Diagnostic and Therapeutic Approach to the Anorectic Cat (2001), Stanley Marks, World Small Animal Veterinary Association World Congress 2001 - and secondly, because doing so may cause diarrhoea.

Mix a little of the new food with your cat's favourite food to start with, and gradually increase the proportion of the new food, over a period of several days or even weeks. There is no need to rush the introduction of any new food, prescription or otherwise, go at your cat's pace. Diet considerations in pets with kidney disease (2008) is a video presentation by Dr CL Langston which says you can take as long as 4-6 weeks to introduce a prescription food if necessary. It may also help to start with to put a little tuna water (the water in which tuna is packed) on the food to moisten it and make it taste a little better. You could also try warming the food. Some people have found puréeing the tinned food makes it more attractive to their cats.

Many cats refuse to eat prescription renal diets. If you are lucky enough to have a cat who will eat one, don't buy too much at first. It is a truth universally ackowledged that as soon as you buy 24 cans of a food, your cat will refuse to eat it.

Hill's has ten tips on introducing renal diets.

When a Cat Refuses Prescription Food

Despite your best efforts, you may fail to persuade your cat to eat these foods. It can be particularly scary if your vet returns your cat to you after a session on intravenous fluids and informs you that if you cannot persuade your cat to eat the veterinary diet, you are effectively killing him or her. Well, I didn't succeed with Tanya and Thomas, so I'm a failure too. But I know more about it now, so here are some tips.

Firstly, don't try to introduce such a food when your cat is sick - see above for more about this. Secondly, take as long as you need - as long as 4-8 weeks if necessary.

Also try a different prescription food - some cats love one brand, but hate the others. You can find lists above of the various UK prescription diets and US prescription diets. Many vets can give or sell you one can of various varieties, so you can try to find one your cat likes.

Another solution is to mix the prescription food with the lowest phosphorus food your cat will eat, or to add a topping of something tempting (see Persuading Your Cat to Eat).

If you cannot persuade your cat to eat any of these foods, please do not feel too despondent. As discussed above and on the Nutritional Requirements page, many experts consider that a low protein diet is not essential in the early stages of CKD. In fact, feeding a low protein diet early in CKD may be counter-productive, leading to weight and muscle loss. Cats Exclusive Veterinary Center states that it is better not to feed prescription diets to thin cats or cats with poor appetites. The Merck Veterinary Manual states "Animals in this stage [IRIS Stages 1 and 2] should be fed standard, commercially available maintenance diets, unless they are markedly proteinuric."

Remember, starvation is far more life-threatening. Cats eat to live rather than live to eat, and if they do not like what is offered, they may simply refuse point blank to eat. This lack of food intake is particularly worrying with cats, because cats who do not eat may develop a condition called hepatic lipidosis (fatty liver disease) where the liver starts to function abnormally. Feline hepatic lipidosis: therapeutic considerations (2011) is a presentation by Dr PJArmstrong to the 36th World Small Animal Veterinary Association World Congress which mentions that hepatic lipidosis can develop after only 2-7 days of not eating; and it can be life-threatening. Even if the cat does not develop hepatic lipidosis, not eating can be a risk. In Nutritional management of renal disease (2008) Presentation to the World Small Animal Veterinary Association World Congress Dr K Sturgess says "It is vital that the cat eats something, as body protein catabolism will have more serious adverse effect on CRD than almost any diet."

In The kidney patient: what's for dinner? (2010) A Presentation to the World Small Animal Veterinary Association World Congress, Dr T Francey states "By individual coaching most dogs and cats can be switched to renal diets and it is important to realize that this change should be made slowly over weeks to months if necessary. In advanced CKD, dietary changes are certainly more difficult and affected animals are less likely to accept diets to which they have not been used. Feeding these animals necessitates either a compromise with more palatable (and less optimal) diets or the use of assisted feeding strategies including feeding tubes."

So you see, it is more important that your cat eats something than that he/she eats the prescription foods. When Thomas was seriously ill after initial diagnosis, we fed him whatever he would eat (ham), and then tried to provide a more suitable diet once he was stable. If your cat won't eat the prescription diet, you may be able to add some of the other elements of a prescription diet, such as additional B vitamins, separately. Naturally, you should aim to feed a food as low in phosphorus as possible. You can also consider a feeding tube if you wish.

So do try to get your cat on a prescription diet, over a period several weeks if necessary, but if you simply cannot persuade your cat to eat these foods, then do not lose too much sleep over it. You have to consider your cat's quality of life: would you want to spend the rest of your life eating a food you detest? See below for possible alternatives.

Feeding Prescription Food to Other Family Cats

It seems that many vets suggest that it is acceptable to feed a CKD prescription diet to other family cats. I do not understand this. If the food is so potent that it is available by prescription only, how would it miraculously have no effect on other, healthy cats? The answer is that it will have an effect: non-CKD cats fed a CKD prescription diet for any lengthy of time run the risk of malnutrition, particularly young cats and kittens, because of the low protein content of such foods.

Even for an older cat, it may not be wise to feed a lower protein diet if the cat is basically healthy. In Feeding the older cat to optimize health and longevity (2003) A Presentation to the Waltham Feline Medicine Symposium 2003, Dr LM Freeman states "some nutritionists actually recommend that older cats eat a higher protein level than younger cats. The jury is still out but for older cats without significant kidney disease, it is wise to avoid low protein diets unless there is a specific indication such as severe renal or hepatic disease."

I know it can be tricky feeding a multiple cat household, so you may have to compromise e.g. perhaps leave out prescription food for all the cats when you are out of the house, but feed the cats separately when you are home. But do always supplement a non-CKD cat with normal, non-CKD prescription cat food. Apart from anything else, this will save you money - prescription foods are expensive.

Other Commercial Foods Back to Page Index

Choosing a Commercial Non-Prescription Food
- Low Phosphorus
- High Quality Protein
"Natural" or "Premium" Foods
Fancy Feast
UK Choices
US Choices

Choosing a Commercial Non-Prescription Food

If you are unable to persuade your cat to eat the prescription diets, you will have to look into feeding other foods instead. Although prescription diets are the ideal (see above), keeping weight on and your cat eating regularly are usually more important than feeding prescription foods.

The main options are other commercial cat foods or a homemade diet. Many senior foods are relatively low in phosphorus and protein, so they may be a possible alternative. However, they may also be lower in fat, which is not ideal for cats who are already on the thin side.

As far as possible you want to replicate the benefits of a prescription CKD food, which has reduced phosphorus, protein and sodium levels, added potasssium, higher levels of B vitamins and essential fatty acids, and sometimes increased fibre. Unfortunately it is not known exactly what is in the prescription diets that makes them effective. You can try adding B vitamins and essential fatty acids to your cat's food separately if necessary. Not all CKD cats need additional potassium but if yours does, your vet can recommend a potassium supplement. This leaves the levels of protein, phosphorus and sodium to be considered.

Do not introduce any new food suddenly, follow the guidelines for introducing prescription foods.

The US Food and Drug Administration has some information on interpreting cat food labels which may help you to choose a good quality food.

Pet Education explains more about the guidelines of AAFPO (Association of American Feed Control Officials). Note that the amounts given here are minimums.

What is a Low Phosphorus Level?

Phosphorus is in virtually every food. Healthy kidneys excrete excess phosphorus from the body, but CKD kidneys cannot do this effectively, so eventually most CKD cats develop high phosphorus levels (this will show in their blood tests). This can make them feel ill and make the CKD progress faster. Controlling phosphorus levels in food i.e. reducing your cat's phosphorus intake so there is less excess phosphorus for the kidneys to excrete, is an important way to help keep your cat doing well, or to get him/her on the road to recovery.

What is a low phosphorus level in food? Ideally, as mentioned by Dr Scott Brown in Management of feline chronic renal failure (1998) Waltham Focus 8 (3), you want your cat to eat food with less than 0.5% on a dry matter analysis (DMA) basis.

Of course, you also need your cat to eat. Therefore you may need to have a less ambitious goal initially of feeding a food containing less than 1% phosphorus. And if your cat's phosphorus levels (as shown in blood tests) are not too high, you have a bit more room for manoeuvre. But the ultimate aim is to feed your cat a food containing as little phosphorus as possible (most prescription foods have a phosphorus level of around 0.4%-0.7%).

If you think you have found a food which is low in phosphorus, please be sure that you are looking at it on a dry matter analysis (DMA) basis. The labels on tins usually do not provide information on a DMA basis, so that apparently low level of phosphorus is unfortunately unlikely to be accurate. For this reason I have created tables of many UK and US foods showing their phosphorus levels. You can find these tables via the dry matter analysis link earlier in this paragraph or from the sidebar on the left.

What is a High Quality Protein?

Protein is a molecular structure made up of a number of amino acids which are essential for the body to repair and maintain itself.

Cats have a higher need for protein than most other species because, unlike dogs or humans, they cannot manufacture certain amino acids (e.g taurine) within their bodies but instead have to obtain them from their food. These missing amino acids are only found in meat, and therefore cats must eat meat in order to obtain these amino acids. This is why cats are known as obligate carnivores.

During the breakdown of dietary protein in the digestive process, waste substances are created which are filtered out of the blood by the kidneys and excreted via urination. This is sometimes referred to as removal of nitrogenous wastes. Unfortunately damaged kidneys find it harder to do this, which is why BUN levels rise in CKD. Therefore the goal is to feed a protein with the correct balance of amino acids to provide the cat with the ability to maintain and repair bodily tissues but in a form which needs as little breaking down as possible. That is what we mean in this context by "high quality protein."

Some people criticise the quality of the protein in prescription diets. These foods may not have the type of protein that you would consider high quality for yourself (e.g. organic chicken breast) but the manufacturers do spend a lot of money trying to create foods that are low in protein but which contain high quality protein from the CKD perspective.

If you feed a commercial food, you can compare the phosphorus levels to those in prescription foods quite easily, but it is harder to compare the protein levels for this reason. The prescription diets have a protein content of around 30% on a DMA basis, so when choosing a commercial food, I would advise at least trying to find one with protein around this level and with meat rather than grain proteins if possible.

I know some people dislike feeding food with grains, and try to avoid ingredients such as corn. One grain where I have fewer concerns is corn gluten meal. Corn gluten meal is actually the protein part of corn. As obligate carnivores, cats require a particular mix of amino acids, and corn gluten meal contains all of the ones that cats need. Evaluation of meat meal, chicken meal, and corn gluten meal as dietary sources of protein in dry cat food (2005) Funaka M, Oka Y, Kobayashi S, Kaneko M & Yamamoto H, Namikawa K, Iriki T, Hatano Y & Abe M The Canadian Journal of Veterinary Research 69 pp299-304 found that corn gluten meal is almost as bioavailable as chicken meal. I would not choose a food that had corn gluten meal as its first ingredient but if it is further down the ingredient list, it would not be a concern to me.

Choosing a Food: Food Tables in Order of Phosphorus Content

In order to make it easier for you to choose an appropriate food, with the help of a few members of Tanya's Support Group I have compiled food data tables showing the phosphorus, protein, sodium and fat levels in many cat foods available in the UK and the USA, including the prescription diets, so you can make comparisons. Many of the UK foods are available in other parts of Europe, whilst most of the US foods are available in Canada. People in Australia should check the tables for both countries.

"Natural" and/or "Premium" Foods

People often assume that I feed so-called "premium" foods. However, I myself am not a fan of most premium foods: they contain fruits and vegetables including cranberries, inappropriate for CKD cats, and in my opinion are unnecessarily complicated foods. Many of these foods seem to me to be designed to appeal to the humans buying them, not to the cat. The Association of American Feed Controls Officials itself admits "Because cats and dogs do not select their own foods, and their human owners do, it is not rare at all that labeling and marketing information is designed to appeal to the latest trend in marketing human products."

Cats have very little need for fruits and vegetables - normally they would only eat the small amounts contained in a mouse's stomach, and even those would be pre-digested by the mouse - so I do not see the attraction of all those carrots, sweet potatoes and blueberries for my cats. Some of these foods, such as Wellness, are also acidified - many commercial foods are, unfortunately, but again this is not suitable for a CKD cat.

If you do decide to feed this type of food (and I know some cats do enjoy them), check the food tables to find those with the lowest phosphorus levels.

Fancy Feast

Fancy Feast often seems to be considered to be a "bad" food. I've never quite worked out why this is, but I get the impression Fancy Feast is considered to be akin to "junk food" that is full of by-products. That's what many humans seem to think anyway. Most cats, however, love Fancy Feast, to such an extent that in some circles (my house) it is known as "kitty crack."

Many Fancy Feast flavours are not particularly complicated foods. Not only that, but, because many flavours do not contain added gluten, Fancy Feast was not affected by the 2007 petfood recalls, unlike many so-called premium brands. And from a CKD perspective, some of the tinned flavours are not excessively high in phosphorus for a non-prescription diet.

In fact, until mid 2010, the Fancy Feast flavours with the lowest phosphorus levels had phosphorus levels of under 0.5%, similar to those of the lowest phosphorus CKD prescription food. Unfortunately Purina decided to change their formulations and sadly no Fancy Feast flavour now has a phosphorus level below 1%. This is higher than you ideally want, but may be worth considering if your cat simply won't eat anything else. The pâté-style foods (labelled Classic) tend to have higher levels of phosphorus (1-2%). The marinated and grilled flavours tend to have high sodium levels, so would not be a good choice for cats with high blood pressure. The Appetizers are not complete foods, so should not be fed exclusively. You can check the food tables for more information on the levels of phosphorus and sodium in the different Fancy Feast varieties.

I'm not claiming that Fancy Feast is perfect. Some flavours contain a preservative called sodium nitrate (or nitrite). Nitrite poisoning in cats and dogs fed a commercial pet food (1997) Worth AJ, Ainsworth SJ, Brocklehurst PJ & Collett MG New Zealand Veterinary Journal 45(5) pp193-195 reports on the effects of this preservative on some cats (note: there is no evidence that the food used in this study was Fancy Feast).

But basically, most cats do seem to love Fancy Feast, and even those who are not feeling too good may eat Fancy Feast. Some cats on Tanya's Feline CRF Support Group have eaten nothing but Fancy Feast for years, and have done well on it, with the addition of phosphorus binders when needed (i.e. if their blood tests show phosphorus levels that are too high).

The pâté-style foods (labelled Classic), whilst too high in phosphorus to use as a regular diet in most cases, are often easier for cats with poor teeth to eat than the other types (grilled, marinated etc.), and can also be mixed with water until smooth and used for syringe feeding or as a base for mixing medications.

Therefore if you live in the USA, I would recommend at the very least keeping a few cans in the cupboard in case of need. It was the only thing Indie would eat when she was sick once.

The nearest UK version of Fancy Feast, judging by the tins, seems to be Purina Gourmet Gold. Unfortunately it does not appear to have the same "kitty crack" appeal of Fancy Feast, plus it seems to have much higher levels of phosphorus. However, it may be useful to try this in times of crisis. I am still working on trying to find a really good, tasty, low phosphorus non-prescription food for UK CKD cats.

Foods for Cats with Other Conditions (Diabetes, Food Allergies or IBD) Back to Page Index

For cats with diabetes and CKD, please see the Diabetes page regarding diet for both conditions.

Generally speaking, you need to control IBD over CKD, because it's academic what food you feed if your cat can't keep it down. If your cat has IBD or food allergies and has been on a limited ingredient diet, you may be able to continue with this diet because some of these foods are pretty low in phosphorus. For example, Hill's z/d has only 0.67% phosphorus on a dry matter analysis basis in the dry version and 0.64% in the tinned. Hill's d/d Duck and Pea dry food is 0.72%. Unfortunately, the Royal Canin IVD limited ingredient diets, which my cats found very palatable, have changed since I used them and now have very high levels of phosphorus (Rabbit and Green Pea is 1.42%) so are unsuitable for CKD cats.

I know some cats do better on grain-free foods, plus grain is a poor source of protein for cats. I am planning to add whether a food is grain-free to my food data tables in due course.

Homemade Foods Back to Page Index

Some people feed their cat a homemade diet, either raw or cooked. Since cats have very complex nutritional needs, this is not something which should be undertaken lightly, you need to do a lot of research in order to ensure that you are providing correct levels of essential nutrients. Pet Diets claims that "one survey found that 90% of the homemade diets prescribed by over 100 US veterinarians were not nutritionally adequate for adult dogs or cats". They also state that few recipes in books or on the internet have been properly tested to ensure they are nutritionally complete.

It is particularly important to get the ratio of phosphorus to calcium correct, and to ensure that you are providing enough taurine - taurine deficiency can cause blindness and heart failure. You also need to be particularly careful with raw diets since these may increase the risk of salmonella poisoning.

If you want to look into the option of a homemade diet further, here are some sites with information on homemade diets, though please note, I would be very careful about using a diet with a high amount of carbohydrates as some of these sites recommend since cats have no nutritional requirement for large amounts of carbohydrates. Please check with your vet before using any of these diets.

Home Prepared Dog and Cat Diets (2010) Dr P Schenck has recipes from a vet. Scroll down to Cat Recipe Nutritional Breakdowns Renal, and click on http next to Cat Recipe Nutritional Breakdowns Renal. An excel file will download with five different recipes for CRF cats. Please note the comment about working with your vet.

USDA National Nutrient Database is a database where you can search for any food ingredient and get a nutritional breakdown, including phosphorus and protein levels.

Kingstown Cat Clinic provides a recipe for Hill's homemade CKD food. This recipe was apparently originally provided by Hill's to vets to offer to people whose cats would not eat a commercial diet, so I presume that is where this vet practice got it from.

Feline Future - an introduction to the cat's nutritional needs and how to prepare a homemade diet; it includes a diet for CKD cats.

Petdiets - in the USA has veterinary nutritionists who can design a personalised diet for your cat if required.

University of California Davis - in the USA can devise a diet to suit your cat if your vet contacts them and provides current bloodwork. The personalised diet costs around US$65 (2002).

Balance IT is a site run by veterinary nutritionists who can provide you with customised recipes for you to make homemade (cooked) food for your cat, although they do not appear to offer recipes specifically for CKD cats. Supplements are also available.

The American College of Veterinary Nutritionists can help you find a veterinary nutritionist in the USA.

Food Cautions Back to Page Index

The following are not recommended for your CKD cat:

Onion and garlic
Foods "for urinary tract health"
Raw food diets
Fish, particularly tuna

Onion and Garlic

Please do NOT feed anything containing onions to your cat, EVER: onions contain an alkaloid disulfide compound which causes a cat to form something called Heinz antibodies - these antibodies trigger a serious form of anaemia which can kill. Particularly susceptible cats may only need to eat a tiny amount of onion for this to happen. Some people believe the same caution applies to garlic, which is a member of the onion family.

Pet Education has information on both onion and garlic.

ASPCA has detailed information on onion and also mentions garlic.

Allium species poisoning in dogs and cats (2011) Salgado BS, Monteiro LN & Rocha NS Journal of Venomous Animals and Toxins including Tropical Diseases 17(1) pp4-11 found that all allium species can be toxic to cats and dogs but that cats are 2-3 more times susceptible to damage than other species. It states that poisoning can occur if a 10lb cat eats 10oz (250g) of onion and that it can still be dangerous even if the cat eats smaller amounts over several days.

Allium species poisoning in dogs and cats (2005) Cope RB Veterinary Medicine 100 (8) pp562-566 mentions that onions, garlic, leeks and chives are potentially toxic to dogs and cats, and that problems may occur after consumption of a single large quantity or repeated consumption of small amounts, even of dietary supplements rather than garlic or onion themselves.

The National Research Council in the USA provides a summary of the findings from the Committee on Examining the Safety of Dietary Supplements for Horses, Dogs and Cats (2008) and states that the committee was unable to determine a presumed safe intake level of garlic for cats.

Pet Diets is a site owned by Dr Rebecca Remillard, a veterinary nutritionist, which states "the possibility of developing a Heinz body hemolytic anemia appears to be variable between pets, and it is not possible to predict which animals may or may not have such a reaction to onion or garlic."

Feline Advisory Bureau reports on sixteen cases of allium poisoning in cats dealt with by The Veterinary Poisons Information Service (VPIS) in the UK, which is part of the Medical Toxicology Unit at Guy's and St Thomas' Hospital in London. Follow up details were only available for four of these cats. One died, two recovered. As for the fourth, "anaemia and jaundice were ongoing problems at the time of follow up after a cat had eaten garlic cloves."

San Francisco Chronicle has an article by a vet which mentions both onion and garlic.

Heinz body anaemia in cats is a paper by J Tarigo-Martinie and P Krimer of the University of Georgia College of Veterinary Medicine.

Haematologic changes associated with the appearance of eccentrocytes after intragastric administration of garlic abstract to dogs (2000) Lee KW, Yamato O, Tajima M, Kuraoka M, Omae S, Maede Y American Journal of Veterinary Research 61(11) pp1446-50 found that HCT levels reduced in dogs fed garlic extract, and Heinz bodies were detected. The conclusion was that "foods containing garlic should not be fed to dogs". Cats are even more sensitive to Heinz body anaemia than dogs, so this advice applies even more so to cats.

Foods for Urinary Tract Health

People often assume that foods which state that they are designed to "support urinary tract health", or "magnesium-controlled", or words to that effect are intended for CKD cats, but this is not the case.

This type of food is acidified because it is actually designed to treat a different kind of problem to CKD called FLUTD (Feline Lower Urinary Tract Disease). These foods are not intended for CKD cats at all, because CKD cats tend to have quite high acid levels anyway. They may also have the effect of increasing the amounts of potassium lost in the urine, which is bad for most CKD cats.

You should also avoid foods that contain cranberries or additional Vitamin C for similar reasons. These foods are also unsuitable for cats with calcium oxalate stones EXPAND

Raw Food

I sometimes hear from people who think a raw food diet will solve all their CKD cat's problems. I wish it were that simple! I'm not opposed to raw diets per se, I considered feeding one myself during the 2007 pet food recall scandal. But feeding raw is not a magic cure for CKD, and there are possible problems:

It can be hard to know the protein and phosphorus content of the food you are feeding (the USDA Nutrient Database may help with this - link below).
CKD cats are immune compromised, so are more at risk of infection from raw foods. A recent study (Septicemic Salmonellosis in Two Cats Fed a Raw-Meat Diet (2003) Stiver SL, Frazier KS, MauelMJ & Styer EL Journal of the American Animal Hospital Association 39 pp538-542), found that raw foods may carry a greater risk of salmonella poisoning. The incidence of salmonella in cats generally is very low, but it is a very nasty disease, and immune-compromised CKD cats may be at greater risk.
Survival of Salmonella Copenhagen in food bowls following contamination with experimentally inoculated raw meat: effects of time, cleaning and disinfection (2006) Scott Weese J & Rousseau J Canadian Veterinary Journal 47(9) pp887–889 J Scott Weese and J. Rousseau found that salmonella could persist in bowls used to hold raw meat despite thorough cleaning. The study states that this was surprising, "particularly their survival following soaking in bleach and washing in a dishwasher at 85°C. Bleach is typically a highly effective disinfectant that would be expected to kill Salmonella spp. However, bleach is less effective in the presence of organic debris, so possibly the small amount of food residue in the bowl was enough to permit survival of the Salmonella sp. in some cases. This likely accounts for the finding that only scrubbing followed by soaking in bleach was effective at reducing the Salmonella sp. contamination. However, even this method of disinfection did not completely eliminate Salmonella bacteria in all bowls."
Salmonella is not the only risk: Raw meat diets spark concern (2005) is a news report by the Journal of the American Veterinary Medical Association which found that 99% of raw meat samples intended for dogs were contaminated with a variety of bacteria. Some people believe that freezing the food before feeding kills pathogens but The New Zealand Food Safety Authority explains that this is not the case.

If you already feed a raw diet which your cat enjoys and with which you have had no problems, I would not insist that you stop, though please do discuss it with your vet. If you have not previously fed raw, I would not recommend starting it because of the possible risks of infection and because it can be quite a change for an already sick cat. There are a few commercially available raw foods which are pasteurised.

If you nevertheless do decide to try raw, please switch your cat over gradually, as you should do with any new food. And please ensure you are feeding a balanced diet. It's not just a case of plonking a piece of raw chicken on a plate and thinking you're cracked it. You need the correct balance of nutrients, and it isn't easy. Please see homemade foods for more information.

USDA National Nutrient Database is a database where you can search for any food ingredient and get a nutritional breakdown, including phosphorus and protein levels.

Fish, Particularly Tuna

Fish is not an ideal food for cats for a number of reasons:

If you feed a cat any fish diet exclusively, the cat can develop a condition called steatitis (yellow fat disease), which is caused by a Vitamin E deficiency resulting from the imbalanced diet. Firstly the cat becomes very nervous, and then becomes hypersensitive in all the nerve endings of its skin, so it is very painful for the cat to be touched. Pet Place has some information about this condition (no need to register, just click on Close at the bottom of the pop-up). The treatment is massive doses of vitamin E under a vet's supervision, and discontinuing any food containing vegetable oil or mineral oil because this will deplete the body's stores of vitamin E even more. Armed Forces Institute of Pathology discusses a case of steatitis in a cat (click on Case Study III) - this cat was put to sleep.

Fish lacks taurine, an amino acid which cats need to obtain from their food. A lack of taurine in a cat's diet can cause heart and eye problems. Baton Rouge Abyssinians has some information about taurine requirements in cats.

One study, Evaluation of dietary and environmental risk factors for hyperthyroidism in cats (2000) Martin KM, Rossing MA, Ryland LM, DiGiacomo RF, Freitag WA Journal of the American Veterinary Medical Association 217(6) pp853-856, found that "cats that preferred fish or liver and giblets flavors of canned cat food had an increased risk" of developing hyperthyroidism.

Tuna can be a problem for other reasons:

Firstly, it can be a very addictive food for some cats, to the extent that they will refuse to eat anything else.

The US Food and Drug Administration has guidelines on the amount of tuna that pregnant women can safely eat. However, the US Environmental Working Group, which worked on the studies with the FDA, believes that human-grade tuna has unusually high levels of the toxic metal methylmercury. They recommend that pregnant women should not eat tuna at all, and that children should eat tuna no more often than once a week. Human-grade tuna tends to consist of the white "meat", while animal-grade tuna tends to consist of the lower grade red "meat", so, at least in theory, animal-grade tuna could contain more pollutants. A 2003 study in The Lancet indicates that eating tuna may not be a problem for pregnant women and children after all (Web MD has a report on this), but I think it might be wiser to err on the side of caution with a sick CKD cat. A tuna fish diet influences cat behavior (1988) Houpt KA, Essick LA, Shaw EB, Alo DK, Gilmartin JE, Gutenmann WH, Littman CB, Lisk DJ Journal of Toxicolology & Environmental Health 24(2) pp161-72 found that "Cats fed the tuna had elevated tissue levels of mercury and selenium."
You might decide to feed human grade tuna instead, but that does not avoid another problem associated with tuna, namely vitamin B1 (thiamine) deficiency. Cats who eat tuna regularly can develop this problem - symptoms are often neurological and include dilation of the pupils, loss of balance, seizures and death if left untreated. Pet Place has some information about this (no need to register, just click on Close at the bottom of the pop-up), as does Healthy Pet. Provet UK has information on this and on the dangers of feeding fish to cats generally.

As you can see, feeding fish regularly has some serious health implications for cats. A little fish occasionally is unlikely to be cause for concern, and feeding it for a few days during a time of crisis should not be a problem (in fact, if you're in the UK, I find feeding a bit of fish from the chippy - batter removed - can help with poor appetite in many cats), but I would not recommend feeding it for any length of time or too often, especially tuna.

Commercial Fish-Based Foods

Please also read the section immediately above about fish and tuna.

I tend to divide fish-based commercial foods into two camps:

the "old school type", which are often mixed with other ingredients (e.g. Chicken & Tuna) and which look like, well, catfood; and
the newer type foods which often contain fish only. These are often advertised as "natural ingredients" and "high quality" and tend to look like something that would be served to humans in a fancy restaurant.

These newer style foods are becoming increasingly popular with manufacturers, but in most cases they are actually manufactured in Thailand, which seems to be doing an amazing job marketing these foods. Brand names include Weruva, Soulistic, Best Feline Friend and Tiki Cat in the USA, and Schesir, Almo Nature and Cosma in Europe. Many manufacturers are introducing some of this style of food as part of their general range e.g. some of the Fancy Feast Elegant Medley foods.

Most commercial cat foods based on fish are usually complete because they do not only contain fish, and are formulated with additional ingredients such as taurine and Vitamin E to prevent problems. The Merck Veterinary Manual has more information on this (scroll down to thiamine). However, you do need to check the can closely because some commercial fish-based foods are not complete foods e.g. Applaws in the UK.

Unfortunately, the newer type foods which only contain fish tend to be extremely low in both fat and calories, so you may find that your cat either needs to eat several cans a day (very expensive) or loses weight on such a food.

Personally speaking, I don't think I would choose to feed commercial fish-based foods exclusively. I also would not feed tuna-based ones longer-term exclusively - The Merck Veterinary Manual states that "there are reports of commercial cat food causing severe neurologic disturbances in cats fed an exclusive tuna diet for 7-11 months." However, most cats do seem to love the newer style fish-based foods in particular, so they may be helpful at times when your cat's appetite is poor.

One possible compromise is to add the water in which tuna is packed to your cat's prescription or other diet in order to make it more palatable. See tuna water for more information.

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This page last updated: 31 December 2011

Links on this page last checked: 16 December 2010