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  • Renal Diets For Cats – What You Need To Know

    Renal Diets For Cats – What You Need To Know

    Chronic kidney disease (CKD) is frequently diagnosed in cats. It is defined as being a progressive disease, slowly disabling the functions of the kidneys over an extended period, usually three months or longer. Although it is not a disease that can be cured, veterinary treatment and changes in your cat’s lifestyle can slow down the progression and allow your cat to have a good quality of life, with some cats living for several years after their diagnosis!

    Which Diet Is Right?

    Feeding cats with chronic kidney disease (CKD) can be difficult, as the current advice is to provide a diet limited in protein and phosphorus. Some brands of commercial cat food offer specialist veterinary diets that claim to fulfil the specific needs of cats diagnosed with CKD. Although these diets have proven to be beneficial, some contain ingredients that are known allergens, such as cereals, and are not always particularly digestible or palatable for cats. When deciding on the best diet for a cat that has been diagnosed as suffering from CKD, it is important to assess your cat’s willingness to eat the food, as cats suffering from CKD can easily become anorexic. Keeping your cat eating should remain a higher priority than feeding a specialist diet, however, we always recommend working closely with your vet to ensure you are doing what is right for your cat.

    How Important Is Protein?

    Cats with CKD may well benefit from lower levels of protein compared to healthy cats. The need to lower the protein content of the food, is not, however, believed to be as important as the need to ensure the food is low in phosphorous.

    When protein is metabolised, uremic toxins are created in the body. Healthy kidneys will filter toxins out of the blood, excreting them from the body. However, if the kidneys are damaged and unable to work as efficiently, these toxins can build up in the body causing a condition called azotaemia. Symptoms of azotaemia include weight loss, appetite loss, vomiting, and lethargy.

    Regardless of the level of protein used in your cat’s food, it is best to ensure that the protein source is highly digestible, and free of meat and animal derivatives, animal by-products, and meat meal. High-quality protein that is easy to digest puts less stress on your cat’s kidneys. If your cat’s blood tests show that they have high phosphorus levels, it is essential that you restrict the phosphorus in your cat’s food to help decrease the stress on their kidneys.

    The Importance Of Low Phosphorus

    Cats on a high phosphorous diet have been observed to have more severe levels of kidney inflammation and deterioration. The kidneys filter phosphorus from the blood, so when the kidneys are damaged, the levels of phosphorus in the blood can rise to dangerous levels, eventually combining with the calcium in the blood. These elements combining can damage the kidneys even further by forming mineral deposits in the soft tissue surrounding the organs, a process known as mineralisation.

    Certain meats are naturally high in phosphorus so are best avoided. Organ meats such as chicken liver, sardines, lentils, brewer’s yeast, and cereals are all high in phosphorus, so pet foods containing these ingredients should not be fed to a cat with CKD.

    Don’t Forget About Hydration!

    It is also vital that cats diagnosed with CKD are well hydrated. Due to the excess urine produced as a result of the lack of kidney function, cats with CKD will require higher levels of hydration. Dehydration in cats with CKD can also lead to acute kidney failure, therefore, feeding primarily a high-quality wet food diet is recommended due to its high moisture content. Wet foods containing jelly, gravy, or sauces are best avoided, as these foods may have a higher salt or sugar content. Wet foods where the meats are cooked in their juices are likely to be a healthier alternative.

    Although not all cats will drink water from a bowl, fresh drinking water should be available at all times.

    The Potential Of Using Fish Oils

    The use of omega oils as a supplement for cats with CKD has promising results. Eicosapentaenoic Acid (EPA) is a beneficial omega oil found in marine sources such as fish and is a proven anti-inflammatory. This anti-inflammatory response is believed to aid kidney health and may be beneficial to cats diagnosed with CKD.

    Liquid fish oil supplements may also be used to add palatability to food, especially if your cat is not accepting a new diet. Plant-based omega oils should not be used, as the omega oil Alpha-Linoleic Acid (ALA) can cause an inflammatory response that could be detrimental to your cat. This is especially important if their kidneys are already inflamed. Ingredients such as flaxseed oil and linseed oil contain high levels of ALA, and your cat’s body is unable to convert this omega oil into the beneficial EPA. Therefore, we would not recommend foods with these ingredients if your cat has CKD.


    Providing a suitable diet for a cat diagnosed with CKD can be difficult. A veterinary or prescription diet may not necessarily be suitable for your cat, however, there are alternatives available. Being aware of the nutritional content of your cat’s food is important, as well as taking into account the quality of the protein and any other important information that is listed on the pet food label. If you suspect your cat may have CKD, always consult your vet before changing your cat’s diet. Your vet will be aware of the specific results relevant to your cat’s kidneys and any other complicating factors, which might influence what foods should be fed to your cat.

    If your cat is already diagnosed with CKD and you would like to discuss further options in regards to nutrition and diet, contact our team at The Thoughtful Pet Food Store and we will be happy to assist!