My 10 year-old dog was just diagnosed with chronic kidney disease, and I was told she needs to eat special food. What does this mean for her?
Chronic kidney disease (CKD) is the most common kidney-based disease in dogs. Waste products are normally filtered out of the blood by the kidneys and excreted in the urine, but dogs with CKD will end up with an accumulation of these waste products in the bloodstream as the filtering process breaks down. CKD occurs on a spectrum, progressing through four stages with each subsequent stage reflecting a more severe phase of the disease than the last. Your veterinarian can help you understand the various stages of CKD and identify the current stage that applies to your dog.
CKD can occur in dogs of any age, but it is the most common illness in dogs over the age of eight. The most common clinical signs of CKD are increased thirst/drinking and increased urinating. Other clinical signs may include lethargy, lack of appetite, vomiting, weight loss, and bad breath. The clinical signs of CKD become more severe as the disease progresses. Many dogs with CKD also have high blood pressure and their hypertension should be treated appropriately.
"CKD can occur in dogs of any age, but it is the most common illness in
dogs over the age of eight."
What role does nutrition play in managing CKD?
There are four core goals for managing CKD in dogs:
- 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
Nutrition addresses all of these goals. Commercial diets for dogs with CKD are developed to prioritize these key goals. When compared with normal maintenance adult dog food, a kidney support diet contains less protein, sodium and phosphorus and increased omega-3 fatty acids. These diets are formulated to help dogs with CKD avoid metabolic acidosis.
How do nutritional requirements differ for dogs with CKD?
Diseased kidneys are not as effective at excreting waste products from the body through the urine. One consequence of CKD is a decreased ability of the kidneys to concentrate the urine. In order to continue to rid the body of its toxins despite more dilute urine, the body compensates by stimulating greater thirst. This makes it critical for you to provide your dog with an unlimited supply of fresh water. Canned food may help increase your dog’s intake of moisture, but this is not a well-established fact.
Decreased dietary protein appears to slow the progression of CKD by decreasing the workload on the kidneys to excrete protein waste products. Less protein also means less need for the excretion of protein itself through the filtration mechanism of the kidney, which helps preserve kidney function. The recommended range of protein on a dry matter basis for dogs with CKD is 14-20%.
"Decreased dietary protein appears to slow the progression of CKD by decreasing
the workload on the kidneys to excrete
protein waste products."
Limiting dietary phosphorus in dogs with CKD appears to help delay the progression of CKD, although the precise mechanism is unknown. The recommended phosphorus range on a dry matter basis for dogs with CKD is 0.2-0.5%. Since phosphorus content is related to protein content, it is impossible to achieve these lower levels of phosphorus without limiting protein content.
Omega-3 fatty acids:
Dietary omega-3 fatty acids reduce protein “leaking” through the kidneys. They also help reduce the production of inflammatory compounds that create oxidative stress to the tissue of the diseased kidneys, thus contributing to slowed progression of CKD.
How can I make good nutritional choices for my dog with CKD?
A kidney support diet for dogs with CKD will contain the following key components on a dry matter basis:
Protein 14 – 20%
Phosphorus 0.2 – 0.5%
Sodium ≤ 0.3%
Omega-3 fatty acids 0.4 – 2.5%
Your veterinarian will help you choose an appropriate formulation for your dog. It is critical to maintain adequate calorie density in order to support good body condition, so food portion calculations and regular weigh-ins are important. Commercially available kidney support diets tend to be quite palatable because it is so important for these dogs to eat in a way that slows the progression of their CKD. If needed, adding water, tuna juice, or low sodium chicken broth may increase the flavor and acceptance.
As CKD progresses, the protein level of the food may need to be further decreased, and the bioavailability of that protein increased. Your veterinarian is your best resource for determining the best nutritional choice for your dog as CKD progresses.
CKD is frequently diagnosed in aging dogs. Feeding an appropriate nutrient profile to slow the progression of this disease contributes to both life expectancy and quality of life.
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