Nutritional Management of Chronic Kidney Disease in Dogs and Cats

Chronic kidney disease is a relatively common issue, especially in our aging canine and feline populations with nutritional management of the condition being a mainstay of treatment. Understanding how kidney diseases progresses and why nutrition nutritional management is so important may not only help guide owners in choosing the right diet but also help guide companies wishing to create diets to help manage this condition.

How kidney disease progresses

The kidneys are responsible for filtering and reabsorbing various proteins and electrolytes such as sodium, chloride, calcium, phosphorus, and potassium. In certain instances the kidney allows these substances to enter the urine for excretion from the body and in other instances, these substances are reabsorbed so the body can further utilize them.

When there is a loss of 75% of the kidney’s functional components, we begin to see changes in the blood work including increased blood urea nitrogen (BUN) and creatinine with a decrease in the kidney’s ability to concentrate the urine. With decreased kidney function, the kidneys are no longer able to process the protein that is normally filtered. Instead, these proteins induce further inflammation in the kidney, which leads to the increased protein being excreted in the urine.

Changes in blood pressure affect the functional component of the kidney. High blood pressure can lead to further kidney damage and kidney damage can lead to high blood pressure.

When the kidney retains phosphorus, parathyroid hormone release is stimulated. Typically, this hormone signals the kidney to get rid of more phosphorus in the urine. However, since the kidney is unable to get rid of the phosphorus effectively more and more parathyroid hormone is released. Hyperparathyroidism is the result of this cycle and also results in increased calcium release from bone resulting in increased kidney mineralization and further inflammation in the kidney.

Why nutritional management of chronic kidney disease is important

A few studies have been performed examining the impact of commercial therapeutic diets on the management of chronic kidney disease. In one study of 50 cats, the median survival time was 633 days in the cats on the kidney diet and 264 days for the cats eating a maintenance diet.

Another study of 38 dogs with stable chronic kidney disease evaluated a diet formulated to be similar to grocery store brand foods compared with a therapeutic diet. In this study, the median survival time was 594 days in dogs on the therapeutic diet and 188 days in the dogs on the maintenance diet. Dogs on the therapeutic diet had an increased time of uremic crisis.

In another study, 45 cats with stable chronic kidney disease were evaluated after transitioning onto a therapeutic diet or a maintenance diet. 91% of these cats accepted the diet they were placed on throughout the study. None of the cats on the therapeutic diet went into a uremic crisis, while 22% of those eating the maintenance diet passed away.

Main dietary goals

The main dietary goals for dogs and cats with kidney disease are:

• Decreased protein: While the protein content should be decreased, the protein quality should be of good quality with all amino acid requirements exceeded. Having a diet that is also high in energy density can help to preserve lean body mass from being utilized and support the pet during periods of decreased intake.
• Decreased phosphorus: Decreasing the phosphorus content of the diet will help to decrease excess parathyroid hormone secretion, which is correlated with the progression of chronic kidney disease.
• Decreased sodium and chloride: Reduced sodium intake helps to reduce the chances of increased blood pressure and progression of chronic kidney disease.
• Increased Omega-3 fatty acids: Omega-3 fatty acids decrease inflammation and are considered protective in chronic kidney disease. They may also help to maintain body weight.
• Decreased acid load: Pets with chronic kidney disease have increased acid load, feeding foods that promote a less acidic urine and blood may help them compensate.

Why an over-the-counter diet designed for growth or maintenance should not be used

Over-the-counter diets are designed to benefit the majority of the pet population. They are typically high in protein, sodium, and chloride than is appropriate for the management of chronic kidney disease. In addition, prescription therapeutic diets are restricted in phosphorus below recommended daily amounts and therefore are for supplemental feeding only and are often sold as prescription diets so that they don’t end up being fed to a pet that shouldn’t receive a restricted phosphorus diet. Therapeutic diets are formulated to match those that have proven to help increase survival time in patients with the disease or have undergone studies showing them to help increase survival time in patients with kidney disease.

 

Follow us on LinkedIn for the latest updates on all things happening here at BSM Partners.

About the Author

Renee Streeter is a Doctor of Veterinary Medicine and a Diplomate of the American College of Veterinary Internal Medicine (Nutrition). She obtained her Bachelor's degree in Animal Science from Cornell University and served as a farm animal nutritionist for a major feed company before attending veterinary school at Ross University. Her clinical rotations were done at Cornell University’s college of veterinary medicine, where she stayed on to do her Clinical Nutrition residency. While working in a large general practice and doing clinical nutrition consultation, Dr. Streeter also founded her own veterinary nutrition consulting company and currently helps industry clients through her position as the Nutrition Practice Principal at BSM Partners.