Nutrition for kidney failure in dogs
Nutrition can be used to improve kidney failure in dogs by acting at three levels:
- Improving the clinical signs
- Controlling macro- and micronutrition
- Delaying the progression of the disease
Water consumption in kidney failure in dogs
It is essential to increase the patient’s water consumption to prevent dehydration. This is not always easy, so you can use tricks such as spraying water on dry foods or giving the dog a moist diet.
Importance of palatability
Dogs with kidney failure may suffer from nausea, vomiting, anorexia, stomach ulcers, and altered smell and taste. This leads to decreased appetite and sometimes malnutrition.
Malnutrition reduces healing capacity, increases the risk of infection and diminishes the animal’s overall strength. The dog should be gradually switched to a renal diet over 2–4 weeks.
Fats are an ally in kidney failure in dogs
The main benefits of supplementing the diet with omega-3 fatty acids are that they provide twice as much energy as carbohydrates, they are very palatable and they are a source of fat-soluble vitamins.
Studies have shown that a high fish oil content decreases the number of structural kidney lesions, controls hypertension and reduces proteinuria (Brown, 1996).
Amino acids and proteins
An adequate diet for kidney failure in dogs requires a very closely controlled protein intake. Reducing protein catabolites improves the signs of azotaemia. Furthermore, because of their high phosphorus content, proteins cause metabolic acidification that worsens renal function.
Despite these restrictions the diet must meet the dog’s nutritional requirements, so that endogenous proteins are not mobilised. The quality of the protein must also be taken into account, as it must meet essential amino acid requirements while simultaneously minimising the amount of nitrogenous waste products.
The role of phosphorus
Kidney failure in dogs often causes secondary hyperparathyroidism. Phosphorus intake must be restricted from the outset. A study by Finco in 1992 showed that diets with a high phosphorus content were associated with a more marked reduction in glomerular filtration rate and lower survival.
Sodium
Both excesses and deficiencies are bad. An excess can lead to hypertension and oedema while too little can aggravate extracellular dehydration and acidosis.
Supplementation with B vitamins
Dogs with kidney failure need to consume more B vitamins to compensate for their loss due to increased urine output.
Fibre
Soluble fibres improve digestive health (Simpson, 1998) and stimulate the growth of the intestinal microbiota (Younes, 2004; Verbrugghe, 2010).
The intestinal microbiota consumes plasma urea and produces propionate, which is amino acid sparing.
Antioxidants
Kidney failure in dogs causes an increase in oxidative stress. This aggravates interstitial fibrosis, glomerulosclerosis and glomerular hypertension. The remaining healthy kidney tissue is forced to hyperfunction, which generates a lot of free radicals that need quenching.
