Nutritional Management of Chronic Renal Disease

Rajeev Kumar MishraL2015V38M

College of veterinary scienceGADVASU, Ludhiana, Punjab

• Maintain the normal balance of fluid and minerals within the body.

• Any condition which damages the kidneys is referred to as kidney or renal disease.

• In some cases, dogs may show early warning signs of kidney disease. However, signs of serious illness only appear after 75% of the kidneys’ function has already been lost.

• A simple blood test and urinalysis are all that is required to detect kidney disease.

What is kidney disease?

Pathogenesis of Renal Damage

• The concentration of free intracellular calcium is very low. Increased free intracellular calcium damages and kills cells and is the most important reason for cell death. Increased extracellular calcium or phosphorus can increase intracellular free calcium concentration. • Abnormal extracellular calcium and phosphorus concentration also causes calcium and

phosphate crystallization in nephrons. Crystals cause inflammation, scarring and nephron loss.

• Causes of high extracellular calcium include lymphoma and parathyroid gland tumours that secrete excess parathormone or parathormone-like substances. • Excess dietary phosphorus, low dietary calcium to phosphorus ratio, low magnesium

intake, and renal disease resulting in a failure of phosphorus excretion are all causes of renal calcium and phosphate crystallization.

Calcium and Phosphorus

Vitamin D Excess

• Vitamin D is necessary for dietary calcium and phosphorus absorption. Excess vitamin D promotes absorption of excess dietary calcium and phosphorus.

• Excess dietary vitamin D is toxic and has the potential for being the most toxic vitamin. Toxic levels

promote deposition of calcium and phosphate as crystals in the kidneys, heart and major blood vessels.

Hypertension• High blood pressure is relatively uncommon in dogs and cats compared to

humans.• Chronic renal disease is the most common cause for high blood pressure in dogs

and cats. • Hypertension may be the most critical factor causing progression of renal

damage. • Hypertension results from increase renal blood flow needed to sustain increased

work load for remaining nephrons.• One primary renal burden is excretion of waste products resulting from protein

metabolism.• Hypertension and the damage it causes is managed by restricting sodium

intake. Drugs should not replace dietary management to correct hypertension.

Acidosis and Ammonia

• The kidneys play an important role in maintaining acid base homeostasis. Dietary protein is metabolized to acid products that the kidneys must excrete. These acid products result primarily from the metabolism of sulphur-containing amino acids and phosphates. • Renal excretion of acid produces ammonia which is toxic to kidney cells. Renal

ammonia formation can be reduced by feeding a diet that minimizes acid. • Sulphur-containing amino acids and phosphates are highest in animal proteins.

Plant proteins are low in sulphur amino acids and high in salts and minerals such as potassium and magnesium which promote alkaline rather than acid conditions.• The acid effects of a diet can be reduced by giving an alkalinizing agent such as

sodium bicarbonate, potassium citrate, or calcium carbonate.

Lipids

• Abnormal lipid metabolism is found in humans and sometimes in animals with renal disease. • The abnormalities may result from renal disease and some may contribute to its

progression. Abnormal changes include hyperlipidaemia and possibly hypercholesterolemia. • Management can include reducing dietary cholesterol and saturated fats.

Some benefit may be gained by feeding more polyunsaturated fat.

• The food your dog eats plays an important role in his overall health and well-being. If your dog is diagnosed with kidney or renal disease, modifying his food can help manage the disease.

• Recent studies in dogs and cats have shown both a reduction in the complications associated with renal failure, and an increase in life expectancy by feeding die

• Specific recommendations regarding dietary therapy will vary from patient to patient and need to be based on clinical and laboratory findings.

Dietary Protein Selection And Restriction

• Reducing dietary protein also decreases renal excretion of waste products. Reduced protein diets limit

1) proteinuria, 2) glomerular damage, and

3) progressive loss of renal function.• Protein restriction generally reduces phosphorus intake, it causes calcium

phosphate crystallization which damages nephrons.• The optimal value of a restricted protein diet is most importantly determined

by feeding proteins with high biological value.

• Egg protein has the highest biological value (set at 100)

Food Biological Value

milk protein 92

chicken 78

soybean protein (tofu) 73

oat protein 65

rice protein 64

corn protein 45

Biological value for vegetable protein is much lower than that for animal protein, more protein must be consumed and that increases waste for renal excretion.

Affected dogs require 2.0 to 3.5 grams protein per kilogram of body weight per day.

Feeding a diet containing a high quality protein such as casein maintains an adult dog at a protein level of 6.5 percent of the diet's dry matter. In general, feeding high quality protein diets containing eight to 10 percent protein maintains adult dogs.

The amount of protein to feed cats with kidney disease is 24 percent crude protein (minimum requirement for an adult cat; 3.5 grams per kilogram of body weight).

The diet must provide a proper balance between the amounts of crude protein and calories. For maintenance of healthy adult cats the ratio of grams of protein to mega calories of energy should be at least 65.

In cats with chronic kidney disease reduce this ratio to 55 during the early stages of disease and to about 45 as the severity of kidney failure progresses.

Dietary Phosphate Restriction• Dietary phosphorus is reduced in proportion to renal impairment. These changes are not usually evident until

renal functional capacity is reduced to 25 percent or less.• Based on this, dietary phosphorus intake should decrease to 25 percent of normal.• The National Research Council (NRC) recommends that normal dogs receive 89 milligrams phosphorus per

kilogram body weight per day. There is little information from studies on cats to show how much phosphorus a normal adult should receive. The level of phosphorus is about 1.3 percent in commercial pet foods.

• Nutritionists recommend a low dietary level of phosphorus, about 0.35 percent for both dogs and cats with chronic renal disease. The dietary ratio of calcium to phosphorus should be greater than 1.0; an even higher ratio may be beneficial. Calcium can be supplemented except when blood calcium is increased.

• Blood phosphorus levels can be reduced by phosphorus binders given orally. Calcium carbonate binds phosphorus and can be used unless blood calcium is high. Other binders include phytin, antacid salts of magnesium or aluminium.

• Magnesium can help correct a low magnesium to phosphorus ratio but it can also result in hypomagnesemia, which must be avoided. Phosphorus is low enough in the following diets that binding agents are unnecessary.

• In summary, to restrict phosphorus feed a diet that is low in phosphorus and has the proper ratio with calcium. If more severe restriction requires some of the other measures, renal disease is so severe that it is not likely to respond well.

• Protein restriction relieves hypertension because renal blood flow lessens. This hypertension can be managed by two other means, both being dietary. Reduction of dietary sodium is essential for normalizing blood pressure.

• Commercial dog foods are high salt diets. Manufacturers include up to one percent sodium chloride in dry dog foods, which provides approximately 95 milligrams sodium and 147 milligrams chloride per kilogram of body weight per day. With kidney disease sodium is restricted to 15-50 milligrams sodium per kilogram of body weight daily. If necessary, sodium intake is restricted to the NRC recommended minimum daily requirement of 11 milligrams sodium per kilogram of body weight.

• Cats tolerate diets containing one percent salt but that level is excessive. A level of 0.24 percent salt may be necessary for managing cats with chronic renal disease.

• Reduction of hypertension is also possible with weight reduction in obese dogs. A relationship has been established between obesity and hypertension in dogs.

• Medications can be used to manage hypertension. They may be necessary with severe renal disease; until then hypertension is managed dietary.

Dietary Salt Restriction — Controlling Hypertension

Dietary Potassium Restriction or Supplementation

• Chronic renal disease greatly increases urine production in some dogs. Such animals can lose large amounts of potassium and become deficient. Commercial dry dog foods contain from 0.70 to 0.85 percent potassium. The NRC recommends a dietary level of 0.44 percent potassium. Hypokalaemia animals should be given one to 6 mEq (about 40 to 235 mg) potassium per kilogram body weight per day.• Cats are more likely to develop hypokalaemia than dogs. Cats require supplementation with

potassium to a dietary level at least 0.5 to 0.6 percent. (The minimum dietary recommendation by the NRC is 0.4 percent.) Because sodium reduces potassium levels, the dietary ratio of potassium to sodium is maintained at 2 to 1 or greater. Acidosis complicating chronic renal disease can worsen hypokalaemia. Drugs for acidifying urine can also cause acidosis.• Hyperkalaemia is serious and life-threatening; potassium intake must be reduced. Specific

treatment for hyperkalaemia involves intravenous glucose (with or without insulin) or bicarbonate solutions.

Dietary Lipid Selection and Restriction• Reducing dietary saturated fat and cholesterol may benefit dogs with

chronic renal disease. In addition, polyunsaturated fatty acid-rich foods such as fish or vegetable oil are fed to supply unsaturated fatty acid and caloric needs. • Some experimental studies suggest that polyunsaturated fatty acids may

adversely affect renal function in chronic renal disease. • Low-fat diets are unpalatable and anorexic cats with chronic renal disease

are unlikely to eat any low-fat diet. • The dietary fat content on a dry basis should be at least 13 to 15 percent.

Vegetable and fish oils are selected unless others such as chicken fat, offering better palatability, are available.

Vitamin and Trace Mineral Supplementation

• Chronic renal disease is associated with reduced intestinal absorption and increased urinary losses of some trace minerals. Iron and zinc deficiencies are possible and supplements of these elements should be given. • Vitamin deficiencies are also likely because of reduced intestinal

absorption and increased urinary losses. Diets are supplemented with B complex vitamins, vitamin C and vitamin K.

.

Diets for Management of Chronic Renal Disease in Dogs

Eggs and Potato Low Protein, Low phosphorus, High Potassium, Normal Sodium

• 1 cooked whole chicken egg,3 cups potatoes boiled in skin (369 grams)1 tablespoon chicken fat (14 grams)1 1/2 calcium carbonate tablets (600 mg calcium)1/2 multiple vitamin-mineral tablet

• provides 600 k calories, 15.1 g protein, 18.5 g fat supports caloric needs of 18 pound dogprovides phosphorus 53%, potassium 322%, sodium 114% of a dog's daily needs.

• To feed this diet with a normal amount of phosphorus substitute 2.5 grams bone meal powder for the 1 1/2 calcium carbonate tablets

Chicken and Potato Low Protein, Low phosphorus, High Potassium, Low Sodium

• 1/4 cup cooked chicken breast (72 grams)3 cups potatoes boiled in skin (369 grams)2 tablespoons chicken fat (28 grams)1 1/2 calcium carbonate tablets (600 mg calcium)1/2 multiple vitamin mineral tablet

• provides 689 k calories, 18.9 g protein, 26.8 g fat supports caloric needs of 21 to 22 pound dog provides phosphorus 45%, potassium 301%, sodium 54% of a dog's daily needs.

• To feed this diet with a normal amount of phosphorus substitute 3 grams bone meal powder for the 1 1/2 calcium carbonate tablets

Eggs and Rice Low Protein, Low phosphorus, Low Potassium, Normal Sodium

• 1 cooked whole chicken egg, 2 cups cooked rice, white polished, long-grain (320grams)1 tablespoon chicken fat (14 grams)1 1/2 calcium carbonate tablets (600 mg calcium)1/2 multiple vitamin-mineral tablet

• provides 721 k calories, 15.2 g protein, 31.4 g fat supports caloric needs of 23 pound dog provides phosphorus 40%, potassium 30%, sodium 90% of a dog's daily needs.

• To feed this diet with a normal amount of phosphorus substitute 3 grams bone meal powder for the 1 1/2 calcium carbonate tablets

Egg White and Rice Low Protein, Low phosphorus, Low Potassium, Normal Sodium

• 3 whites from whole chicken eggs, cooked2 cups cooked rice, white polished, long-grain (320 grams)2 tablespoons chicken fat (28 grams)1 1/2 calcium carbonate tablets (600 mg calcium)1/2 multiple vitamin-mineral tablet

• provides 693 k calories, 18.8 g protein, 26.8 g fat supports caloric needs of 21 to 22 pound dog provides phosphorus 27%, potassium 43%, sodium 208% of a dog's daily needs.

• To feed this diet with a normal amount of phosphorus substitute 4 grams bone meal powder for the 1 1/2 calcium carbonate tablets

Diets for Management of Chronic Renal Disease in Cats Chicken and Rice Low Protein, Low phosphorus, Normal Potassium, Normal Sodium Diet Providing 55 Grams Protein/1000 K calorie Diet• 1/4 cup cooked chicken breast (72 grams)

1/2 ounce clams, canned, chopped in juice (14 grams)1/2 cups cooked rice, white polished, long-grain (80 grams)1 tablespoons chicken fat (14grams)1/8 teaspoon salt substitute-potassium chloride1 calcium carbonate tablets (400 mg calcium)1/4 multiple vitamin-mineral tablet1/10 tablet B complex vitamin-trace mineral

• provides 297 k calories, 16.3 g protein, 14.5 g fatSee table for caloric needs of cats provides phosphorus 48%, potassium 215%, sodium 169% of a cat's daily needs

• To feed this diet with a normal amount of phosphorus substitute 2 grams bone meal powder for the 1 calcium carbonate tablet

Egg White and Rice Low Protein, Low phosphorus, Normal Potassium, Normal SodiumDiet Providing 53 Grams Protein/1000 K calorie Diet

• 3 whites from whole chicken cooked eggs, 2 ounce clams, canned, chopped in juice (57 grams)1 cups cooked rice, white polished, long-grain (160 grams)1 tablespoons chicken fat (14 grams)1/8 teaspoon salt substitute-potassium chloride1 ½ calcium carbonate tablet (600 mg calcium)1/4 multiple vitamin-mineral tablet1/10 tablet B complex vitamin-trace mineral

• provides 312 k calories, 19.7 g protein, 13.8 g fatSee table for caloric needs of cats provides phosphorus 41%, potassium 341%, sodium 603% of a cat's daily needs.

• To feed this diet with a normal amount of phosphorus substitute 2 grams bone meal powder for the 1 1/2 calcium carbonate tablets

Eggs and Rice Low Protein, Low phosphorus, Normal Potassium, Normal SodiumDiet Providing 45.7 Grams Protein/1000 K calorie Diet

• 2 cooked whole chicken eggs,• 1/2 ounce clams canned, chopped in juice (14

grams)1/2 cups cooked rice, white polished, long-grain (80 grams)1 tablespoon chicken fat (14 grams)1/8 teaspoon salt substitute-potassium chloride1 calcium carbonate tablet (400 mg calcium)1/4 multiple vitamin-mineral tablet1/10 tablet B complex vitamin-trace mineral

• provides 411 k calories, 18.8 g protein, 25.2 g fatSee table for caloric needs of catsprovides phosphorus 69%, potassium 189%, sodium 440% of a cat's daily needs. To feed this diet with a normal amount of phosphorus substitute 1 grams bone meal powder added to 1/2 calcium carbonate tablet

Chicken and Potato Low Protein, Low phosphorus, Normal Potassium, Normal SodiumDiet Providing 57.4 Grams Protein/1000 K calorie Diet

• 1/2 cup cooked chicken breast (142 grams)1/2 ounce clams canned, chopped in juice (14 grams)1/2 cup potatoes boiled in skin (62 grams)2 tablespoons chicken fat (28 grams)1 1/2 calcium carbonate tablets (600 mg calcium)1/4 multiple vitamin-mineral tablet1/10 tablet B complex vitamin-trace mineral

• provides 453 k calories, 26 g protein, 30.6 g fatSee table for caloric needs of catsprovides phosphorus 52%, potassium 198%, sodium 201% of a cat's daily needs. To feed this diet with a normal amount of phosphorus substitute 2 grams bone meal powder for the 1 1/2 calcium carbonate tablets

Commercially available renal diet for dogNutrient

Dry Matter1

%

Protein 15.9

Fat 26.4

Carbohydrate (NFE) 49.5

Crude Fiber 3.6

Calcium 0.91

Phosphorus 0.3

Sodium 0.18

Potassium 0.86

Magnesium 0.073

Vitamin C 155 mg/kg

Vitamin E 632 IU/kg

Omega-3 Fatty Acids Total 1.59

Crude Protein (min) 2.5% Crude Protein (max) 5.5% Crude Fat (min) 4.5% Crude Fiber (max) 1.5% Moisture (max) 82.5% Phosphorus (max) 0.13%

Morsels in GravyThis diet contains 913 kilocalories of metabolizable energy (ME) per kilogram (calculated).One 13.5oz can contains 352 kilocalories of ME on an as fed basis.

Eukanuba Veterinary Diets Renal for dogs

Reduced phosphorus level (0.4%) – soya protein isolate (contains reduced phosphorus) helps nutritionally manage high blood phosphorus.

Moderate levels (18.8%) of high quality animal-based protein – helps to maintain the kidneys’ filtration function.

Omega-3 fatty acids – helps to support the kidneys’ filtration function. Added potassium citrate – helps to manage the acidity-alkalinity balance of

the body.

NUTRITIONAL PROFILE

Nitrogen Trap Fibre System (beet pulp, FOS, Gum Arabic) – helps to increase excretion of nitrogenous waste via the faeces and reducing urinary nitrogen excretion.

ADDITIONAL BENEFITS

Commercially available renal diet for catNutrient

Dry Matter1

%

Protein 29.7

Fat 26.8

Carbohydrate (NFE) 35.9

Crude Fiber 3.8

Calcium 0.72

Phosphorus 0.5

Sodium 0.24

Potassium 1.05

Magnesium 0.053

Taurine 0.43

Vitamin C 134 mg/kg

Vitamin E 713 IU/kg

Omega-3 Fatty Acids Total 0.33

Crude Protein (min)22.5%Crude Protein (max)26.5%Crude Fat (min)19.5%Crude Fiber (max)5.0%Moisture (max)8.0%Phosphorus (max)0.55%Eicosapentaenoic Acid (EPA)* (min)0.24%Docosahexaenoic Acid (DHA)* (min)0.1% -

This diet contains 4061 kilocalories of metabolizable energy (ME) per kilogram or 398 kilocalories ME per cup on an as fed basis (calculated).

Eukanuba Veterinary Diets Renal for Cats

Reduced phosphorus level (0.35%)* – soy protein isolate (contains reduced phosphorus) helps nutritionally manage high blood phosphorus

Moderate level (28%)* of high quality animal-based protein – help to maintain the kidneys’ filtration function

Omega-3 fatty acids – helps to support the kidneys’ filtration function Added potassium citrate – helps to manage the normal acidity-alkalinity

balance of the body

NUTRITIONAL PROFILE

Nitrogen Trap Fibre System (beet pulp, FOS, Gum Arabic)** – helps to increase excretion of nitrogenous waste via the faeces and reducing urinary nitrogen excretion.Dry and canned formulas can be fed separately or mixed – to help maximise acceptance if the appetite is low and with no compromise on your cat’s management.

ADDITIONAL BENEFITS

Patient Evaluation During Dietary Management

• Regular serum evaluation for BUN and Creatinin.

• Improvement of previous presenting clinical sign’s.

• Owner satisfaction.

References• 1. Brown, Scott A. 1994. Canine Renal Disease. In The Waltham Book of Clinical Nutrition of the Dog and Cat. Edited by J. M.

Wills and K. W. Simpson, 313-334. Oxford: Pergamon Press.

• 2. Moraillon, Robert and Roger Wolter. 1994. Feline Renal Disease. In The Waltham Book of Clinical Nutrition of the Dog and Cat. Edited by J. M. Wills and K. W. Simpson,277-291. Oxford: Pergamon Press.

• 3. Grauer, Gregory F. and India F. Lane. 1994. Acute Renal Failure: Strategies for its Prevention. In Nephrology and Urology. Waltham Symposium Number 16. Edited by C. Tony Buffington and James H. Sokolowski, 23-30. Vernon: Kal Kan Foods.

• 4. Kopple, Joel D. 1991. Role of Diet in the Progression of Chronic Renal Failure: Experience With Human Studies and Proposed Mechanisms by Which Nutrients May Retard Progression. Journal of Nutrition 121(11S):S124.

• 5. Polzin, David J., Carl A. Osborne and Larry G. Adams. 1991. Effect of Modified Protein Diets in Dogs and Cats with Chronic Renal Failure: Current Status. Journal of Nutrition 121(11S):S140-S144.

• 6. Leibetseder, J and K. Neufeld. 1991. Effects of Dietary Protein and Phosphorus Levels in Dogs with Chronic Renal Failure.

• Purina International Nutrition Symposium in Association with the Eastern States Veterinary Conference. 15 January. 35-38.

• 7. Polzin, David J. 1991. Can Diet Modify Progression of Chronic Renal Failure? Purina International Nutrition Symposium in Association with the Eastern States Veterinary Conference. 15 January. 29-33.

• 8. Lewis, Lon D., Mark L. Morris and Michael S. Hand. 1987. Small Animal Clinical Nutrition III. 3d ed. Topeka: Mark Morris Associates. 1-15.

• Royal Canin Pet Nutrition

• Hill's Pet Nutrition

• Eukanuba Pet Nutrition