Crafting a Kidney-Friendly Diet for Cats with Chronic Kidney Disease

Kidneys play a vital role in maintaining the body functions. Two of these major roles include removing waste from the blood and conserving the water. When kidney fails to function normally, waste products like urea and phosphorous begin to remain within the body causing toxicity and sometimes, may also result in dehydration because more water is lost through urine than normal.

Chronic kidney disease (CKD) is characterized by the irreversible and progressive loss of kidney function, leading to various metabolic imbalances and complications. CKD can be caused by various factors like – aging, congenital abnormalities, infections, toxins, and certain diseases such as diabetes or high blood pressure.

The early stages of CKD may not show noticeable symptoms, but as the disease progresses cats may experience –

Diagnosis of CKD involves blood and urine tests to evaluate kidney function, as well as imaging techniques like ultrasound. Nutritional management plays a crucial role in the overall treatment of cats with CKD, helping to slow disease progression, maintain quality of life and improve survival rates. Cats with (CKD) have a poor ability to maintain body weight. As CKD advances, loss of body weight contributes to morbidity and mortality.

The dietary strategies include management of key nutrients like protein, phosphorus, fat, salt, fibre and energy content of the food.

Protein restriction is a key component of the nutritional management of cats with CKD. When the kidneys are unable to work properly due to tissue damage, they may have difficulty in processing and eliminating nitrogenous waste products generated from protein metabolism. By reducing the amount of protein in the diet, the workload on the kidneys is decreased, helping to slow down the progression of the disease and minimize symptoms. When a general reduction in protein intake is necessary, it’s crucial to provide high-quality protein sources like egg, beef, fish, chicken which are easily digestible and contain essential amino acids. Protein is essential for maintaining muscle mass, immune function, and overall health. Therefore, the focus should be on providing a controlled amount of quality protein rather than completely eliminating protein from the diet.

Kidneys play a vital role in maintaining a balance of phosphorus in the blood. However, in CKD, the kidneys lose their ability to regulate phosphorus levels effectively. As a result, phosphorus accumulates in the blood and leading to various complications. So, feeding a diet low in phosphorus is a fundamental strategy in managing CKD which is done by providing food with less phosphorus content like rice, egg white, chicken thigh and avoiding dairy foods, processed meat and processed cheese which have high phosphorus content. Also, some Commercial pet foods are available with reduced phosphorus content. In some cases, it may be challenging to maintain adequate phosphorus levels. In such situations use phosphorus binders like aluminum hydroxide, calcium lactate and chitosan. These binders prevent P absorption in GI tract and reduce phosphorus levels in the blood.

We have to limit the intake of foods high in saturated fats (e.g., fatty cuts of meat, full-fat dairy products) and trans fats (e.g., fried and processed foods). It is important to include healthy fats like unsaturated fats, particularly polyunsaturated fatty acids (Omega-3 fatty acids). They have anti-inflammatory properties and may help to reduce proteinuria (excess protein in the urine) and slow the progression of kidney disease. Good sources of omega-3 fatty acids include fatty fish (e.g., salmon, sardines), flaxseeds, chia seeds, walnuts and fish oil. Diet supplemented with omega -3 fatty acid with antioxidants such as vitamin E and vitamin C are better effective together.

Salt intake is just one aspect of the overall dietary management of CKD because in CKD, the kidneys may not function optimally, leading to fluid retention. Excessive salt intake can worsen fluid retention and leads to oedema and increased blood pressure. Sodium is the main component of salt, and reducing sodium intake is a key strategy in managing CKD. The daily sodium intake for pets with CKD may vary depending on the stage of the disease and other factors. Generally, a low-sodium diet should be provided that includes foods and treats <1 mg sodium per/kcal. Avoid high salt treats like cheese, bread and commercial cat treats containing high salt treats.

The addition of fermentable fibers in the diet of cats with CKD help to decrease the excretion of nitrogenous waste through kidney by increasing metabolic fecal nitrogen due to increase in microbial flora in colon due to fermentable fibers. So, diet of cats with CKD should be supplemented with fermentable fibers such as beet pulp, fructooligosaccharides, gum arabic.

In CKD, patients may have specific energy needs based on their stage of kidney disease, overall health, and activity level. The daily energy requirement of cats with CKD is 1.1-1.4 times the patient’s resting energy for maintenance. So, you have to provide adequate calories to prevent protein catabolism in the body and increase non-protein energy sources like fat, carbohydrate in diet.

Homemade diet can be prepared for pets with chronic kidney disease (CKD) but, requires careful consideration of above dietary strategies. Following ingredients can be chosen to prepare homemade diet – egg, fish and chicken (as source of protein), salmon or sardine fish, flaxseed cake, flaxseed oil, chia seeds, walnuts and fish oil (as a source of fat), rice (as a source of carbohydrate) and beet pulps (as a fibre source) with addition of very less quantity of salt to make food palatable.

The primary goals of the nutritional management of cats with CKD are to reduce the workload on the kidneys, maintain a proper nutritional balance and control complications such as electrolyte imbalances, acid-base disturbances and hypertension. It can be achieved through nutritional intervention such as lower dietary phosphorus, lower dietary sodium, and lower dietary protein while being rich in high-quality protein, providing essential fatty acids, antioxidants and B-complex vitamins. Also make sure you are providing high moisture diet to your pet.

(Dr. H. S. Madhusudhan – MVSc, PhD – Assistant Professor, Department of Animal Nutrition, Veterinary College, Hebbal, Bengaluru)