Nutritional Requirements for Cats with Chronic Kidney Disease (CKD)

VITAL FUNCTIONS OF KIDNEYS

The kidneys have a variety of important functions. These include:  

• Removing waste products from the blood
• Conserving water in the body
• Producing urine
• Regulating the levels of certain essential minerals such as potassium and sodium
• Initiating the production of red blood cells in the bone marrow

KIDNEY DYSFUNCTION AND CHRONIC KIDNEY DISEASE (CKD)

Clinical signs usually present themselves when two-thirds (67% to 70%) of the kidneys are already dysfunctional. Usually damage to the kidneys occurs over a long period of time – months or years. This long-term or chronic condition results in kidney failure and often progresses to chronic kidney disease (CKD) which is mainly a problem of older cats.

With kidney disease the kidney function declines and toxic waste products like urea and phosphorous begin to build up in the body. This affects body functions and can make the cat feel nauseous and lethargic. Decreased kidney function also leads to dehydration because more water than normal is lost in the urine.

MANAGEMENT AND TREATMENT SLOWS THE PROGRESSION OF CKD

When the kidneys are damaged, they unfortunately seldom recover. However, with proper management and treatment, the condition usually progresses slowly giving your cat a number of years of good quality life.

WHAT ARE NUTRIENTS AND NUTRITION?

Nutrients are substances that provide nourishment for organisms to survive, grow and reproduce.
Nutrition is concerned with how the body uses nutrients and how it connects to diet, health and disease.

Sufficient Nutrients are Essential for Cats with Chronic Kidney Disease (CKD)

To effectively manage CKD in cats, certain issues need to be addressed:

1. Symptoms, caused by waste gathering in the blood, need to be managed
2. The imbalance of fluids and minerals need to be improved
3. Sufficient recommended nutrition needs to be ensured
4. The progression of CKD needs to be delayed

An appropriate diet can address all of these objectives.

Special Kidney Support Diet

Special diets for cats with CKD can be prepared at home or are available ready prepared – consult your veterinarian. 

A kidney support diet contains less protein, sodium, and phosphorus, and increased omega-3 fatty acids. This diet helps lower the level of waste products in the bloodstream.

There is no one-size-fits-all diet for cats with CKD, but an appropriate diet generally contains:

1. Less Protein

   Insufficient protein intake can lead to dangerous weight loss. Less protein doesn’t mean no protein. It means a controlled intake of quality proteins. These are proteins that are easy to digest. Some experts may suggest a natural raw diet.

   To encourage a cat with CKD to eat, try to improve the texture, aroma and taste of food.

2. Less sodium

   Because sodium retention and potential high blood pressure are concerns, it is often recommended that sodium intake be restricted.

3. Less phosphorus

   The body needs phosphorus, but it needs healthy kidneys to control the levels, otherwise kidneys will suffer damage. With CKD, kidneys struggle to regulate phosphorus levels. To control phosphorus intake, ask your veterinarian what foods are the safest options.

   Signs that kidney function may have been compromised include absence of appetite, weakness and uncoordinated or uncontrolled movement. Sometimes medication that reduces the absorption of phosphate is necessary (phosphate binder), but this should be discussed with your veterinarian.

4. More omega-3 fatty acids

   If the diet doesn’t already contain them, omega-3 fatty acids EPA and DHA can help protect the kidneys from the harmful effects of CKD.

5. More potassium

   Deficiency of potassium in the bloodstream (hypokalemia) is common in cats with CKD. This leads to muscle weakness, stiffness, and poor hair quality. Low potassium levels may also contribute to the worsening of the kidney failure. Ask your veterinarian about potassium supplementation.

6. More Antioxidants

   Extra antioxidants, such as vitamins C and B, can reduce renal oxidative stress. When the failing kidneys are unable to concentrate the urine, these water-soluble vitamins are lost and affected cats may need daily supplementation.

IMPORTANT

Cats with CKD can easily become dehydrated. If your cat has CKD, make sure he or she always has easy access to fresh water.

Kidney support diets should provide the following:  

• Moderate amounts of high-quality, easy-to-digest proteins
• Low in phosphorus to limit additional kidney damage
• Added fish oil (omega-3 fatty acids) to protect against inflammation
• Enriched in natural antioxidants such as vitamins C and B

DRUG THERAPY IN CONJUNCTION WITH DIET 

Drugs address the treatment of conditions associated with CKD, such as anemia.  When kidneys are weakened the production of red blood cells in the bone marrow is decreased. Many cats with CKD are anemic due to a lack of stimulation of the bone marrow. Drugs have been developed to help stimulate bone marrow production and may be prescribed by your veterinarian.

Proper Nutrition is Vital for Cats with CKD

When it comes to taking care of a cat with CKD, it’s all about addressing underlying causes, treating symptoms and managing nutrition because there is no cure. With treatment and careful management, cats with Chronic Kidney Disease (CKD) can have a good quality of life. 

This article is about the nutritional needs of cats with chronic kidney disease (CKD) and a discussion of:

• Foods that can be beneficial to cats with CKD
• Foods that can be aggravating to cats with CKD

One of the essential functions of the kidneys is to filter the body’s waste. The body makes waste that it cannot use and adds it to blood for transport to the kidney. The kidney then filters the waste out of the blood and into urine for excretion. With CKD the system has difficulty eliminating waste which usually results in:

• Nausea
• Loss of appetite
• Weight loss
• Dehydration

MANAGEMENT OF COMMON CKD SYMPTOMS TO MINIMIZE FURTHER KIDNEY DAMAGE

Although every cat is different, cats with CKD generally have a good quality of life, if these common symptoms are managed:

• Nausea: Because waste products build up in the blood of cats with CKD, they may feel nauseous. Reduce blood urea nitrogenand phosphorus in the diet with low protein foods like egg whites, chicken and tuna. Avoid foods like shrimp.
• Decreased Appetite: Most cats don’t want to eat when they feel nauseous. Veterinarian recommended kidney diets smell good to cats and are high in calories, which means appetite may improve.
• Weight Loss: Because of diminished food intake cats with CKD often lose both muscle and fat. High calorie diets help when cats don’t want to eat. Low-phosphorus proteins support muscle mass.
• Dehydration: Diseased kidneys have difficulty concentrating urine and lose a lot of water. Try canned food, which has more water, or adding low-sodium broth or tuna juice to their water bowl.

BENEFICIAL FOODS

Appropriate quantities of the right foods can help reduce symptoms and promote the health of cats with CKD, making them feel better and live longer.

Vet-approved cat foods with the following characteristics are often recommended:

• Omega-3 Fatty Acids: Essential nutrients that can help prevent/manage disease
• More Potassium: A mineral and an electrolyte to help combat potassium deficiency
• More Antioxidants: E.g. vitamin C or E that removes potentially damaging oxidizing agents

Kidney support diets should provide the following:

• Moderate amounts of high-quality, easy-to-digest proteins
• Low in phosphorus to limit additional kidney damage
• Low Sodium helps address sodium retention and/or possible high blood pressure
• Added fish oil (omega-3 fatty acids) to protect against inflammation
• Enriched in natural antioxidants such as vitamins C and E

Getting rid of the waste products of protein metabolism is hard work, especially for kidneys that have lost some of their function. However, cats with CKD still require protein, but less than healthy cats and it’s important that this reduced amount of protein is of a high quality. The body needs some protein to function properly and to maintain a healthy weight. Calories missing from reduced protein need to be made up elsewhere.

Taste, smell and texture provide appeal

It’s very important that cats, especially those with CKD, eat enough. So, to encourage a healthy appetite, you need to choose foods that smell and taste as good as possible. Texture can also play a role in general appeal.

Aggravating Foods

Excessive quantities of the wrong foods can aggravate or increase symptoms of CKD which can be detrimental for health, reducing quality of life and lifespan of cats with CKD.

Foods that are dry can increase dehydration. Canned foods that have a high-water content can help prevent dehydration.

Foods with hard-to-digest poor quality proteins produce more urea and phosphorous that then need to be eliminated causing the diseased kidneys to work even harder. Choose foods made from moderate amounts of high-quality protein.

Vitamins, Fats and pH Levels

Depending on your cat’s condition and test results, your veterinarian may look at other factors, such as vitamin B, calcium and fat intake as well as blood pH levels.

MONITORING AND ADAPTING TO THE DIFFERENT STAGES

There’s no one-size-fits-all diet plan that can be prescribed for all cats with CKD. Age, possible underlying causes, disease progression rate and individual signs and clinical symptoms all need to be considered when establishing a treatment plan. Plus, the condition needs to be monitored to make sure the plan is still right for the different stages of the disease. When the situation changes, the treatment plan needs to be adjusted accordingly.

MEDICAL MANAGEMENT

You can’t only rely on nutritional changes. Luckily there are effective medications for cats with CKD. The sooner treatment starts, the better. Chronic kidney disease (CKD) requires lifelong treatment and can be challenging for both the cat and its human family. Management of nutrition, hydration, lifestyle, and medical interventions can:

• Slow the progression of the disease
• Increase lifespan and improve quality of life

Role of Nutrition for Cats with CKD

CHRONIC KIDNEY DISEASE (CKD)

Chronic kidney disease (CKD) is the most common kidney disease in cats. With chronic kidney disease the kidneys are progressively and irreversibly deteriorating. In a healthy cat, waste products are filtered out of the blood by the kidneys and excreted in the urine. However, cats with kidney disease will have an accumulation of these waste products in the bloodstream as the filtering process breaks down. This condition is a leading cause of death in domestic cats and is very common in older cats and certain breeds including the Maine coon, Abyssinian, Persian, Siamese, Russian blue, and Burmese.

Unfortunately, CKD is an incurable condition; however, treatment and management of symptoms can improve and prolong the lives of cats with this disease.

TREATMENT AND MANAGEMENT GOALS FOR FELINE CKD

• Control the clinical signs associated with accumulating waste products in the blood
• Minimize problems with fluid and mineral balance
• Sustain adequate nutrition
• Modify/slow the progression of CKD

DIETARY MANAGEMENT IMPROVES QUALITY OF LIFE

Several studies have shown that dietary management plays a key role in cats with CKD.

Nutrition can help to improve quality of life as well as life expectancy which are the two main treatment goals. With the right nutritional adjustments, some symptoms can be managed to bring relief.

Important: Nutritional therapy does not replace medical management. For long-term successful treatment of cats with CKD, medical needs have to be met as well to improve quality of life.

NUTRITIONAL INTERVENTIONS

There’s no one-size-fits-all when it comes to nutritional therapy and various factors need attention to help cats with CKD live more comfortable lives. The physical diet needs attention, of course, but making sure that the affected cat eats enough is also essential. Once a vet-approved plan is in place, you need to monitor the reaction and adjust the diet accordingly, throughout treatment.

HOW TO MANAGE THE NUTRITION PART OF CKD

Treatment outcome can be improved with early nutritional therapy. To help manage CKD in cats, these are some of the nutrition objectives that need to be met after diagnosis:

1. Make sure the affected cat has enough energy to support its body.
2. Address fluid, electrolyte and hormone imbalances as well as metabolic abnormalities.
3. Slow down the progression of CKD.

THREE MAIN ASPECTS OF KIDNEY SUPPORT DIET

In general, a kidney support diet contains less protein, sodium and phosphorus and increased omega-3 fatty acids. There are three main aspects to dietary management:

Water Intake

Dehydration is a major sign of CKD because of the reduced ability of the kidneys to conserve water. It’s crucial for a cat with CKD to maintain a good water intake that may help to slow progression of the disease. Since foods also contain water, feed cats tinned (or sachet) foods because of their high-water content instead of dry foods.

Restricted Protein

Restricted protein content in foods is important for cats with CKD. When protein breaks down in the blood, toxins accumulate; therefore, feeding a reduced protein diet will decrease this process and improve quality of life. This protein restriction should be done with care because too little protein can also be harmful.

Phosphate Restriction

Phosphate restriction can be very beneficial in protecting the kidneys from further damage. Restricting phosphates thus appears to prolong the life of cats with CKD.

OTHER MEASURES

 Intake of the following may need intervention:

• Vitamins: B and C Vitamins lost through increased urination
• Lipid concentrations (lipids are fatty acids or their derivatives)
• Minerals: Phosphorus, calcium, sodium and potassium need to be managed
• Acid-base Balance: Try to keep blood pH within the normal range
• Protein: Restriction can relieve clinical signs, such as vomiting, lethargy, anorexia and bad breath
• Fat: Fat can enhance taste and provide energy to compensate for the missing protein, but not all cats with CKD are able to tolerate higher fat concentrations

REMEMBER: Combine nutritional management with medical management for long-term, successful treatment of CKD in cats.

Consult your veterinarian for effective medications for cats with CKD.