As responsible pet parents, we all wish to improve and extend the quality of our pets’ lives and feeding plays a very important role in controlling many disease progressions (kidney diseases, obesity, skeletal abnormalities, dental pathologies, and gastric disorders etc.)
Correct nutrition is an important tool in disease prevention and a legitimate aid of therapeutic nutrition. The veterinary therapeutic nutrition deals with the knowledge of interaction between nutritional components and patho-physilogical processes of various systems in animals which provide a way to develop new strategies of intervention and control the clinical management of the patient.
Kidney disease: a threat
Kidney disease is one of the life threatening ailments in companion animal and it is second to cancer in causing deaths. Although medicines can cure the disease but prevention is always better than cure. The nutritional modification is one of the strategies to provide health and longevity to patients with kidney disease. Renal Diet – a diet prescribed in kidney disease and designed to control intake of protein, potassium, sodium, phosphorus, and fluids, depending on individual conditions – is an alternative to medicines for prevention and control of renal diseases.
Role of kidney in the body homeostasis
Kidneys keep our pet’s body free of wastes that accumulate during metabolism. They are continually scrubbing the blood free of excess salts, water and metabolites. The kidneys are paired bean-shaped located below the rib cage near the middle of the back. They play a crucial role in regulating the amount of water and electrolytes in the body such as sodium, potassium and phosphorous. Elimination of complex organic compounds, both endogenous and exogenous, maintain a relatively stable blood flow, ionic reabsorption and excretion, control of blood pressure. It also releases three regulatory chemicals viz. erythropoietin, renin, and calcitriol that affect other functions in the body. Erythropoietin stimulates the bone marrow to produce new red blood cells. Renin helps regulate blood pressure, and calcitriol (1-25-dihydroxycholecalciferol) is an active form of vitamin D and is important in maintaining bones and the level of calcium in the body.
In people, hearts are often our weakest organ. In dogs, it is often the kidneys that wear out first.
There is a slow but steady loss of kidney function in all of our pets as they age – so much so, that next to arthritis, renal (kidney) failure is the leading cause of illness in older dogs. Any damage which leads to destruction of the normal kidney function is known as Kidney disease, also known as renal disease, which leads to kidney failure, a situation in which the kidneys fail to function adequately. There are many ailments of kidney of which the important one is divided into two categories depending on the severity and time of kidney failure. The Acute renal failure (ARF) is the sudden loss of the ability of the kidneys to remove waste and concentrate urine without losing electrolytes. While, Chronic renal failure (CRF) is a slowly worsening loss of ability of the kidneys to remove wastes, concentrate urine, and conserve electrolytes. In ARF, there is a rapid progressive loss of renal function, generally characterized by oliguria (decreased urine production), body water and body fluid disturbances; and electrolyte derangement but usually does not cause permanent damage to the kidneys, however CRF is characterized by symptoms such as polydipsia (increased water consumption), polyuria (frequent urination), dilute urine, depression, anorexia, discoloration of teeth, chemical odour to the breath, nausea and vomiting, muscle weakness and exercise intolerance, weight loss, pale mucous membranes because of anaemia, oral (mouth) ulcers, shivering, muscle wasting and diarrhoea.
Prevention and treatment
The objective of dietary management in renal failure is to lessen the metabolic demands on the kidneys and to diminish metabolic end-products that cannot be readily excreted. The successful management of canine kidney disease requires careful food choices, which balances pet’s appetite. It has been known for many decades that once chronic renal disease is established, renal failure often progresses inexorably, even if the underlying cause of the renal disease is eradicated. Typical nutritional interventions include restriction of protein and phosphorus, modification in electrolyte balance, dietary supplementation of polyunsaturated fatty acids (PUFAs) such as omega -3 etc. Nutritional therapy, however, does not simply mean changing the diet; consideration must also be given to ensuring adequate caloric intake and to the method of feeding. Therapeutic measures include initial restoration and maintenance of body fluid balance, supportive symptomatic therapy that aims to minimize disruptions in fluid, acid-base, electrolyte and nutritional status. The Renal food (RF) specifically prepared for dogs suffering with renal diseases helps delay in development of uremia and reduction in the rate of progression of renal failure.
Dietary restriction of protein and phosphorus
High dietary protein with view of weight management and lean maintenance may put animal at risk for diseases related to excessive nitrogen metabolism. Intake of high dietary protein and phosphorus leads to increased risk for kidney diseases. Dietary restriction of protein helps to reduce the renal disorders and is also beneficial in slowing the progression of chronic renal disease. The predominant effect of the low protein diet is to minimize production of uremic toxins so that the patient feels better. Dietary protein restriction may limit the genesis of nitrogen wastes and thus lessen the extent of uremic complications of chronic renal failure such as vomiting and lethargy.
Role of polyunsaturated fatty acids (PUFAs)
Dietary supplementation with polyunsaturated fatty acids (PUFAs) has been considered as a potential therapeutic manoeuvre in chronic renal insufficiency. It helps by altering renal hemodynamics and retards the progression of renal injury in dogs with chronic renal failure.
Modification of electrolytes
High level of serum sodium with systemic hypertension is more frequent in patients with renal disease which may lead to high arterial pressure predisposing progression of renal injury. Hence, dietary sodium restriction may be one of the alternatives to control systemic hypertension in patients with renal disease.
Fermentable or soluble fibre, when added to a dog’s diet, also helps remove toxins from his body. Because of this, it is often an ingredient in commercial diets sold to manage kidney failure in pets. In these diets, the source is sugar beet pulp. Also nowadays prebiotics are gaining movement as fermentable fibre sources in dog’s diets.
In conclusion, there are various nutritional approaches for prevention and treatment of kidney diseases few of which includes restriction of protein and phosphorus, supplementation with omega 3 fatty acids, modification of electrolyte balance. Along with these, there should be proper feeding management and monitoring the proper functioning of the kidney is important. Suggestions are made for water and fat-soluble vitamins, trace minerals and other non-nutrient feed additives based on their activities as free-radical scavengers, immune modulators, anti-emetics, and erythrocyte production stimulators. In future, new avenues in nutritional science like phytonutrients, antioxidants, designer foods and of course nutrigenomic (role of nutrient in modulation gene function) may help solve the puzzle between nutrition and kidney disease.