Chronic kidney disease is a pathology that mainly affects older dogs whose specific origin is unknown but whose clinical manifestations are similar in all conditions.
The prevalence of this disease is around 2% and since the life expectancy of dogs is slowly increasing, it may be that in the future it will be even more frequent.
It is a fatal disease without effective curative treatment, but there are palliative therapeutic options that prolong not only a longer life span but a better quality of life where nutrition plays an elementary role.
What is chronic kidney failure in dogs?
The kidney is an organ with many functions beyond blood filtering and urine production, which would be the best known. It is involved in the production of blood through erythropoietin (or EPO) and is elemental in the metabolism of vitamin D, which requires to be hydroxylated in the liver and kidney to be functional, in addition to many other functions.
The renal failure is a condition in which the kidney is losing its functionality progressively starting the most pronounced symptoms when they have already lost three – quarters of renal function. The first symptom is usually an increase in urinary frequency accompanied by a greater volume of water drunk without achieving optimal hydration.
After this, the symptoms are very varied, but apathy, anorexia, dehydration, anemia and bad mouth odor predominate.
Food for dogs with kidney problems
It is the basis of palliative treatment. It is based on the restriction of certain nutrients and the addition of others to stop the deterioration as much as possible. Both the prognosis of the patient and the effectiveness of treatment depend to a great extent on when it is started, in initial or advanced stages. As may be logical, the results are much better if the disease is stopped in its initial moments.
Regarding nutrition, the points in which food is intervened are:
- Protein: It is not the most important, but the best known. Protein restriction is motivated by uremic syndrome, that is, the number of alterations that come as a result of an increase in serum urea, the most common being gastric ulcers , vomiting, loss of appetite and bad breath . The restriction of this nutrient must be moderate and the quality of the protein must be high both for its digestibility and for its biological value. Currently, in order to consider a kidney prescription dog food, the restriction must be 22% protein, which can be found in physiological feed. Uremic syndrome, despite being present, does not accelerate the deterioration of the kidney directly, but due to anorexia and apathy of the animal, it will drink less water and be more dehydrated.
- Phosphorus: Possibly the most important nutritional restriction in these foods. Unlike the previous one, high levels of phosphorus do damage the kidney, which cannot filter it. Another consequence of phosphorus is secondary hyperparathyroidism, which further aggravates the disease . Phosphorus restriction prevents this pathology, limits kidney damage and prolongs the life of the animal. The levels to which it is restricted are difficult to achieve in physiological feeds since they are around 0.4%.
- Sodium: Although the mechanism is unknown, it has been seen that dogs on a sodium-restricted diet had a longer life expectancy. It has been theorized that it could be hypertensive as in humans, however, it has not been experimentally proven. What has been shown is that sodium restrictions of around 0.2% improve the life span of these animals .
- Vitamin A: It has been shown that high levels of this vitamin cause kidney damage, therefore the diet they follow should be restricted in this vitamin but without being lower than the minimum requirements.
Nutrients for feeding animals with CRI
After having commented on the restrictions, there are also nutrients that help us in a very interesting way in this disease. Some of these are:
- Lipids: Because of their high energy content that leads to obesity, they are tremendously demonized in human food (and consequently in animals). However, this same characteristic is very interesting to us because it allows us to achieve the minimum energy with very little volume (remember that these are patients who tend to anorexia). In addition, it makes the meals more palatable which will help our sick animal to eat.
- Omega 3 fatty acids: They have an anti-inflammatory effect at the tissue level that improves some of the symptoms and also contributes to better renal blood circulation since it dilates the efferent arteriole of the nephrons. They are usually present in greater amounts in fish feed for dogs.
- Vitamin E: Reduces oxidative stress in tissues and helps the animal feel better.
Recommended and not recommended guidelines in feeding for animals with CRI
In this disease, a highly recommended guideline is to give wet food whenever possible as it contributes to better hydration in these patients. This food should ideally be prescribed by the kidneys to ensure that it has the same nutritional characteristics as the dry formulation.
Two brands that have products with these characteristics are the well-known Hill’s and Royal Canin, but there are more. We must ensure that they are prescribed for the kidneys and verify that commercial companies have carried out studies to certify their effectiveness.
On the other hand, there are a series of acts that are not recommended in kidney disease dogs with respect to their nutrition, namely:
- Feeding with non-renal diets : For the reasons explained it is not advisable to give a physiological diet as it will reduce the life expectancy of the animal.
- Non-extruded diets that have not been prescribed by specialist veterinarians : Found online or recommended by acquaintances. These are usually the most common origins of these. They are diets whose composition is unknown and their phosphorus and sodium levels are probably exorbitant, since they are very difficult components to restrict.
- Food or sweets outside the diet : It is ideal to avoid them as much as possible.
- Using bouillon tablets or other products to flavor the water : Although it seems a bit twisted, it is a practice that has happened relatively frequently (enough to warn of the danger of this).
In conclusion, it is necessary to be very demanding with the diet in dogs with kidney problems and prevention plays a key role in the treatment. It is a tough disease for both owners and patients, therefore we must do everything we can to improve the lives of our patients.