What Should a Dog With Kidney Failure Eat?

Chronic kidney disease is a condition affecting mainly older dogs, whose specific cause is unknown but whose clinical manifestations are similar across all cases.

The prevalence of this disease sits at around 2% and, given that dogs' life expectancy is slowly rising, it may well become more frequent still in future.

It is a fatal disease with no effective curative treatment, but there are palliative options that prolong not only a longer life but a better quality of life, and nutrition plays a fundamental part in them.

What Is Chronic Kidney Failure in Dogs?

The kidney is an organ with a great many functions beyond filtering the blood and producing urine, which would be the best known. It is involved in producing blood through erythropoietin (or EPO) and is fundamental in the metabolism of vitamin D, which needs to be hydroxylated in the liver and the kidney to become functional, as well as many other functions.

Kidney failure is a state in which the kidney progressively loses its function, with the most marked symptoms beginning once three quarters of kidney function has been lost. The first symptom is normally an increase in urinary frequency accompanied by a greater volume of water drunk without reaching optimal hydration.

After that the symptoms are very varied, but apathy, loss of appetite, dehydration, anaemia and bad breath predominate.

Feeding Dogs With Kidney Problems

This is the foundation of palliative treatment. It is based on restricting certain nutrients and adding others to slow the decline as far as possible. Both the patient's prognosis and the effectiveness of treatment depend to a large extent on when it is started, in the early or advanced stages. As is only logical, results are far better if the disease is tackled in its early stages.

In nutritional terms, the points at which the food is adjusted are:

• Protein: Not the most important, but the best known. Restricting protein is prompted by uraemic syndrome, that is, the range of disturbances that follow a rise in serum urea, the most recognisable and most common being gastric ulcers, vomiting, loss of appetite and bad breath. Restricting this nutrient should be moderate, and the quality of the protein should be high, both in digestibility and in biological value. Currently, for a dog food to be considered a renal prescription diet, the restriction should be to 22% protein, a level that can be found in ordinary kibbles. Uraemic syndrome, although present, does not directly accelerate the kidney's decline, but through the animal's loss of appetite and apathy they will drink less water and be more dehydrated.
• Phosphorus: Possibly the most important nutritional restriction in these foods. Unlike the previous one, high phosphorus levels do damage the kidney, which cannot filter it. Another consequence of phosphorus is secondary hyperparathyroidism, which aggravates the disease further still. Restricting phosphorus prevents this condition, limits kidney damage and prolongs the animal's life. The levels it is restricted to are hard to reach in ordinary kibbles, since they are around 0.4%.
• Sodium: Although the mechanism is unknown, dogs on a sodium-restricted diet have been seen to have a longer life expectancy. It has been theorised that it might raise blood pressure as it does in humans; experimentally, however, this has not been demonstrated. What has been demonstrated is that sodium restrictions of around 0.2% improve survival time in these animals.

• Vitamin A: High levels of this vitamin have been shown to cause kidney damage, so the diet they follow should be restricted in this vitamin without falling below minimum requirements.

Nutrients for Feeding Animals With CKD

Having covered the restrictions, there are also nutrients that help us in very useful ways with this disease. Some of these are:

1. Lipids: Because of their high energy content, which leads to obesity, these are tremendously demonised in human nutrition (and by extension in animal nutrition). That same characteristic is very useful to us here, though, because it allows the minimum energy to be reached in very little volume (remember these are patients who tend towards loss of appetite). It also makes meals more appealing, which will help our sick animal to eat.
2. Omega-3 fatty acids: They have an anti-inflammatory effect at tissue level that improves some of the symptoms and also contributes to better renal blood flow, since they dilate the efferent arteriole of the nephrons. They are usually present in greater amounts in fish-based kibbles for dogs.

3. Vitamin E: It reduces oxidative stress in the tissues and helps the animal feel better.

Recommended and Not Recommended Practices in Feeding Animals With CKD

In this disease, a highly advisable practice is to give wet food whenever possible, since it contributes to better hydration in these patients. Ideally this food should be a renal prescription diet, to make sure it has the same nutritional characteristics as the dry formulation.

Two brands with products of these characteristics are the very well known Hill's and Royal Canin, but there are more. We should check that they are renal prescription diets and confirm that the manufacturers have carried out studies to certify their effectiveness.

On another note, there are a number of practices that are not advisable in dogs with kidney disease as regards their nutrition, namely:

• Feeding diets that are not renal: For the reasons explained, giving an ordinary diet is not advisable since it will shorten the animal's life expectancy.
• Non-extruded diets that have not been prescribed by specialist vets: Found online or recommended by acquaintances. These tend to be their most common origins. They are diets whose composition is unknown and whose phosphorus and sodium levels are probably wildly high, since these are very difficult components to restrict.
• Foods or treats outside the diet: Ideally these should be avoided as far as possible.
• Using stock cubes or other products to flavour the water: Convoluted as it may seem, this is a practice that has happened with relative frequency (enough to warrant warning of its danger).

In conclusion, we have to be very demanding about food in dogs with kidney problems, and prevention plays a key part in treatment. It is a hard disease for owners and patients alike, so we should do everything possible to improve our patients' lives.

Kibble Suitable for Dogs With Kidney Failure

Special Care by NFNatcane is a range aimed at dogs with various conditions who need high-quality food that is moderate in protein and fat, such as dogs with kidney failure.

It is made with chicken, tuna and duck, hydrolysed to improve nutrient absorption and reduce intolerances. Remember that it should always be your vet who sets the feeding guidance, such as the number of portions, the amount and whether the range is suitable for your dog.