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Diet and Chronic Renal Disease

Renal disease affects an unusually large number of dogs and cats. Renal disease affects one percent of all age dogs and at least ten percent of dogs over 15 years old. These estimates are probably low. The incidence is probably similar for cats. Although chronic renal disease is easily identified, moderate damage is probably more common and not recognized because signs do not appear until renal damage is severe. Early recognition and management of renal disease are important for two reasons. Renal damage is irreversible; animals lose structure and function in affected nephrons. Secondly, renal damage is progressive so if untreated, normal nephrons are destroyed. Management’s goal is to preserve normal nephrons, to halt continuing damage. With progressive damage, mortality is high and treatment is costly; dialysis and renal transplantation are often necessary.

Feeding affected animals a proper diet usually preserves remaining nephron function. Diets must have proper amounts of calcium, magnesium, sodium, and potassium, and often they must be formulated with reduced phosphorus. Concentrations of some vitamins must not exceed requirements. Dietary protein is sometimes reduced to a minimum. Some studies show benefit from reducing protein consumption but other studies show no benefit. The nature of a renal problem determines dietary protein levels. Understanding the development of renal disease is important to its dietary management. A knowledge of causes for renal damage also helps understand how dietary management can prevent chronic renal disease.

Etiology

Acute Disease1-3
Renal disease develops following many acute insults. Acute disease is often caused by nephrotoxins. Common toxins include antibiotics such as aminoglycosides and amphotericin B, antifreeze (ethylene glycol), and non-steroidal antiinflammatory drugs. An important cause of acute renal damage is excess vitamin D. Commonly used rodenticides contain vitamin D which when ingested promote excess calcium absorption. Excess calcium crystallizing in renal tissue destroys nephrons. Poisoning with vitamin D kills by acute renal failure. Acute renal damage also develops when renal blood flow is severely reduced. Additional causes include chronic renal infection or inflammation and disease in other organs.

Chronic Disease1,2
Renal disease is not usually identified until it is chronic, probably because most owners do not recognize clinicial signs of early disease. Many different causes have been suggested to be most important. Fifty years ago the important cause was Leptospirosis infection. Now this disease is rare and other explanations are necessary for its cause. The causes can be similar to those for acute problems. But these causes cannot explain the high incidence of chronic renal disease. Toxins infrequently cause chronic renal damage, even small amounts of toxin that would more likely produce chronic rather than acute damage. Chronic infectious or inflammatory disease infrequently explains chronic renal disease. With these causes, management to correct the primary problem should cause renal damage to stop and renal function to stabilize. What best explains the high incidence of kidney disease in dogs and cats?

Dogs and cats should not be so unique that they have chronic renal disease much more commonly than other mammals, including humans. This frequency may relate to feeding commercial pet foods; the rate has been increasing with their feeding. Commercial foods can cause problems when they contain excess vitamin D; earlier it was noted that this vitamin is indirectly a nephrotoxin.Vitamin D is added to pet foods during processing and manufacturers do not measure its amount in the finished product. As with most vitamins, D is added in excess to insure that an adequate amount remains after the predicted loss of some vitamins during cooking. Manufacturers believe vitamins are safe so that addition of larger amounts should be of little consequence. Who adds the vitamins and how they are measured can be important in the processing of commercial pet foods.

The imprecise addition of vitamin D to milk processed for human consumption has caused vitamin D toxicity that resulted in some human deaths. Could that happen to pet foods? It is not likely that large amounts of vitamin D would be added and result in acute toxicity such as with a rodent poison. But it is possible that "excess but safe" amounts added to pet foods result in subclinical toxicity. Over a period of months or years that excess could eventually damage the kidneys so that they fail, and then cause signs of disease. An unusually high incidence of chronic renal disease in cats has been associated with a brand of cat food containing high levels of vitamin D.

Excessive dietary levels of calcium and phosphorus can also lead to mineralization of kidneys in normal animals. Diets should contain proper amounts of these minerals.

 Pathogenesis of Renal Damage1,4,5

Calcium and Phosphorus
Calcium is present as a free (soluble) and a bound form. The concentration of free intracellular calcium is very low, thousands of times lower than extracellular concentration calcium. Increased free intracellular calcium damages and kills cells and is the most important reason for cell injury and death due to any cause. Anything increasing intracellular free calcium levels damages cells. Increased extracellular calcium or phosphorus can increase intracellular free calcium concentration. Abnormal extracellular calcium and phosphorus concentration also causes calcium and phosphate crystalization in nephrons. Crystals cause inflammation, scarring and nephron loss.

Many different diseases can increase extracellular calcium and phosphorus levels to cause renal damage and failure. Causes of high extracellular calcium include lymphoma and parathyroid gland tumors that secrete excess parathormone or parathormone-like substances. Excess dietary calcium or vitamin D also increases extracellular calcium. 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 crystalization.

Vitamin D Excess
Vitamin D is necessary for dietary calcium and phosphorus absorption. Deficiency of vitamin D was one of the common causes of calcium and phosphorus deficiency (rickets) in dogs some years ago. 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. Chronically diseased kidneys have fewer nephrons that are are overworked, something that contributes to ongoing nephron destruction. Hypertension results from increase renal blood flow needed to sustain increased work load for remaining nephrons. Management is directed at minimizing the renal work load. One primary renal burden is excretion of waste products resulting from protein metabolism. A restricted-protein diet is fed to manage this burden. 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 sulfur-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. Sulfur-containing amino acids and phosphates are highest in animal proteins. Plant proteins are low in sulfur 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 hyperlipidemia and possibly hypercholesterolemia. Management can include reducing dietary cholesterol and saturated fats. Some benefit may be gained by feeding more polyunsaturated fat.

Diagnosis1,2

There are no specific signs alerting owners to renal disease. Nonspecific signs such as increased water consumption, loss of appetite, vomiting, depression, and weight loss are common. These signs are not specific for renal disease, however. Early signs should not be ignored because important signs do not appear until most renal function is lost; the loss is irreversible.

Renal disease is diagnosed by laboratory tests that include urinalysis and blood chemistries. The urinalysis is helpful in evaluating kidney functions to dilute and concentrate urine. It is also helps identify infection and active inflammation. Urinalysis can be normal with renal disease, however, so an evaluation must include additional tests.

Blood chemistry tests include blood urea and often creatinine determinations which increase with chronic renal disease. Blood chemistry tests also include plasma phosphorus and calcium which can increase with reduced renal function. Potassium is also excreted renally and its blood levels can increase with reduced renal function. (With vomiting and inappetance potassium losses can be excessive, resulting in hypokalemia.) When renal disease reduces excretion of acid products, acidosis develops and appears on blood chemistry evaluations as reduced bicarbonate concentration.

A complete blood count identifies anemia, an important complication of chronic renal disease. The kidney produces erythropoietin that is necessary for bone marrow to produce erythrocytes. Erythropoietin production may be deficient with renal disease. Erythropoietin is an important treatment for anemia due to chronic renal disease.

Blood pressure is measured to identify hypertension. Dietary management changes with hypertension.

Other tests to evaluate for chronic renal disease are not essential. Renal biopsy gives information on the extent of damage and is usually done for prognosis. No other tests contribute additional new and useful information for evaluating most animals with chronic renal disease.

Feeding To Restrict Renal Damage1,2,6,7

Dietary Protein Selection And Restriction
Dietary protein is restricted for some dogs and cats with chronic renal disease. That restriction reduces the exposure of nephrons to toxins and reduces their work. As noted above, some products of protein metabolism are toxic so feeding a low protein diet reduces toxin damage. 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. Mostly meat diets are rich in phosphorus and some years ago they caused many problems until manufacturers balanced them by adding calcium. Phosphorus is toxic as already described. It causes calcium phosphate crystalization which damages nephrons. In all of the following diets phosphorus levels are low to very low and that reflects not the protein source as much as protein amount.

The optimal value of a restricted protein diet is most importantly determined by feeding proteins with high biological value. Little of these proteins are catabolized to products (urea, phosphate and sulfate) the kidneys must excrete. Egg protein has the highest biological value (set at 100) and so is ideal for dietary management of chronic renal disease. For comparison, biological value for milk protein is 92, chicken or beef 78, soybean protein (tofu) 73, oat protein 65, rice protein 64, and corn protein 45.8 Egg protein is high in sulfur-containing amino acids, however, but unless acidosis is marked (usually only in severe or terminal cases) eggs are the ideal protein to feed. On the other hand, sulfur-containing amino acids are the first limiting amino acids in milk and soybean proteins. This means that relative to the other essential amino acids they provide the smallest percentage of an animal's requirement. Diets with proteins from vegetables rather than animals are low in sulfur-containing amino acids and produce less acid. However, because 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. Thus, with the possible exception of tofu, protein in these diets is from animals.

Affected dogs require 2.0 to 3.5 grams protein per kilogram of body weight per day. The lower amount can be used when feeding a protein with a high biological value and the higher amount when feeding a protein with low biological value. Feeding low biological value protein requires more work for kidneys with reduced function. 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 protein must have a high biological value. 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 megacalories of energy should be at least 65 (65 grams of protein for each 1000 kcalories fed). 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. The primary biochemical abnormality with loss of renal function is uremia or azotemia. 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. Dogs with chronic kidney disease and azotemia will develop hyperphosphatemia with this dietary level of phosphorus. Nutritionists recommend a low dietary level of phosphorus, about 0.35 percent for both dogs and cats with chronic renal disease. Whatever the level, it must be low enough to prevent hyperphosphatemia. 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 found in vegetable matter and antacid salts of magnesium or aluminum. Magnesium can help correct a low magnesium to phosphorus ratio but it can also result in hypermagnesemia, 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.

Dietary Salt Restriction — Controlling Hypertension
Hypertension of renal circulation may be the critical determinant of renal disease progressing. As noted earlier, 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.

No minimum requirement is established for sodium or salt in cats. 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 dietarily.

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. Potassium depletion can be difficult to identify because blood potassium can be either normal or low. Commercial dry dog foods contain from 0.70 to 0.85 percent potassium. The NRC recommends a dietary level of 0.44 percent potassium. Hypokalemic 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 hypokalemia than dogs. Cats require supplemention 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 hypokalemia. Drugs for acidifying urine can also cause acidosis.

Hyperkalemia is serious and life-threatening; potassium intake must be reduced. Specific treatment for hyperkalemia involves intravenous glucose (with or without insulin) or bicarbonate solutions.

Dietary Magnesium Intake
Urinary tract struvite stones form in cats for a number of interrelated reasons. Diets containing greater than 0.35 percent magnesium was once related to stone formation. In response cat foods were formulated with little magnesium. This resulted in hypomagnesemia, which increases urinary potassium excretion and leads to hypokalemia. Adequate amounts of magnesium are also needed to prevent calcium crystalization and renal stone formation. Dietary magnesium should be 0.10 to 0.12 percent compared to the NRC recommended minimum level of 0.04 percent for cats. Canine requirements are satisfied with a dietary level of 0.05 percent magnesium.

Dietary Energy Intake
Animals with renal disease are fed to maintain normal body weight. If necessary caloric intake is adjusted so underweight dogs regain weight losses and overweight dogs lose weight. Restricting caloric intake to minimum basic needs may be beneficial for slowing the progression of chronic renal disease.

Dietary Lipid Selection and Restriction
Reducing dietary saturated fat and cholesterol may benefit dogs with chronic renal disease. Non-animal protein is needed for that. (As noted earlier it is far more important to select proteins of animal origin in order to feed those with the highest biologic value.)  In addition, polyunsaturated fatty acid-rich foods such as fish or vegetable oil are fed to supply unsaturated fatty acid and caloric needs. These fatty acids relieve hypercholesterolemia and hyperlipidemia in some dogs with chronic renal disease. Some experimental studies suggest that polyunsaturated fatty acids may adversely affect renal function in chronic renal disease. Polyunsaturated fatty acids are precursors for leukotrienes and prostaglandins. High dietary levels may promote formation of inflammatory mediators and thereby worsen renal damage. That is unproven, however, and substituting polyunsaturated fatty acids that produce mediators with weaker inflammatory properties (omega-3 polyunsaturated fatty acids) does not benefit animals with renal disease.

Dietary fats are important for other reasons. Low-fat diets are unpalatable and anorexic cats with chronic renal disease are unlikely to eat any low-fat diet. These cats also suffer from weight loss, and feeding to promote weight must include more than minimal amounts of fats. 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. Iron is necessary for erythrocyte production and with chronic renal disease often causing anemia, additional iron may benefit some. 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. It is dangerous to give additional vitamin D. Commercial pet foods may contain excess vitamin D that can be responsible for chronic renal disease. As mentioned earlier vitamin D promotes calcium absorption and high intracellular calcium damages renal cells.  Protection of the remaining nephrons against further damage is by minimizing dietary vitamin D.

Diets for Management of Chronic Renal Disease in Dogs   

The following diets supply nutrients for a medium-size adult dog, and provide about 10 percent protein (135 percent of needs). Chicken fat improves palatability. Increasing dietary chicken fat decreases the protein percent, however. The diets are all low phosphorus and provide 50 to 75 percent of vitamin D requirements. Some diets contain minimum amounts of sodium and some are low in sodium. Some animals loose excess sodium with chronic renal disease and in such cases iodized salt is used for flavor (one-tenth teaspoon iodized salt can be added). Depending on needs diets contain normal, low or high amounts of potassium. Potassium depleted animals can be fed a low potassium diet if one-fourth teaspoon potassium chloride is added. Magnesium is available to meet required levels. Some diets are low in vitamin B12 which is probably unimportant unless they are fed for many months. Substituting chicken or ground beef for eggs enhances flavor and provides more B complex and B12 vitamins. A vitamin B12 supplement can be given occasionally. The diets are balanced with respect to all other nutrients.

Feeding a diet matched to needs can restore phosphorus, potassium and sodium to normal. Blood chemistry panels are done to monitor plasma concentrations. With normal blood levels dietary mineral levels can be modified. It may not be necessary to continue feeding a very low phosphorus diet; doing so may result in deficiency. To increase dietary phosphorus substitute bone meal powder or tablets for calcium carbonate tablets. For example, to one of these diets providing 45 percent of the phosphorus needs, adding bone meal powder in place of 1 1/2 calcium carbonate tablets increases dietary phosphate to meet NRC requirements. Normal calcium levels are maintained. At the end of each recipe directions are given for restoring normal phosphorus levels.

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

1 cooked whole egg, chicken
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 kcalories, 15.1 g protein, 18.5 g fat
supports caloric needs of 18 pound dog
provides 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 kcalories, 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

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

2 ounces (raw weight) lean ground beef, cooked (57 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 737 kcalories, 18.6 g protein, 32.5 g fat
supports caloric needs of 23 to 24 pound dog
provides phosphorus 43%, potassium 293%, 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 Tapioca
Low Protein, Low phosphorus, Low Potassium, Normal Sodium

3 cooked whole eggs, chicken
2 cups tapioca, cooked, (125 g dry before cooking)
1 tablespoon chicken fat (14 grams)
1 1/2 calcium carbonate tablets (600 mg calcium)
1/2 multiple vitamin-mineral tablet

provides 779 kcalories, 19.3 g protein, 28.9 g fat
supports caloric needs of 25 pound dog
provides phosphorus 40%, potassium 30%, sodium 216% 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

Beef and Tapioca
Low Protein, Low phosphorus, Low Potassium, Low Sodium

4 ounces (raw weight) lean ground beef, cooked (114 grams)
2 cups tapioca, cooked, (125 g dry before cooking)
2 tablespoons chicken fat (28 grams)
1 1/2 calcium carbonate tablets (600 mg calcium)
1/2 multiple vitamin-mineral tablet

provides 845 kcalories, 19.9 g protein, 37.2 g fat
supports caloric needs of 28 pound dog
provides phosphorus 18%, potassium 29%, sodium 55% of a dog's daily needs.
To feed this diet with a normal amount of phosphorus substitute 4 to 5 grams bone meal powder for the 1 1/2 calcium carbonate tablets

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

3 whites from whole chicken eggs, cooked
2 cups tapioca, cooked, (125 g dry before cooking)
1 tablespoon chicken fat (14 grams)
1 1/2 calcium carbonate tablets (600 mg calcium)
1/2 multiple vitamin-mineral tablet

provides 610 kcalories, 14.1 g protein, 13 g fat
supports caloric needs of 18 pound dog
provides phosphorus 6%, potassium 33%, sodium 269% of a dog's daily needs.
To feed this diet with a normal amount of phosphorus substitute 5 grams bone meal powder for the 1 1/2 calcium carbonate tablets

Chicken and Tapioca
Low Protein, Low phosphorus, Low Potassium, Low Sodium

1/2 cup cooked chicken breast (143 grams)
2 cups tapioca, cooked, (125 g dry before cooking)
2 tablespoons chicken fat (28 grams)
1 1/2 calcium carbonate tablets (600 mg calcium)
1/2 multiple vitamin-mineral tablet

provides 763 kcalories, 20.8 g protein, 27.3 g fat
supports caloric needs of 24 to 25 pound dog
provides phosphorus 20%, potassium 22%, sodium 55% of a dog's daily needs.
To feed this diet with a normal amount of phosphorus substitute 5 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 egg, chicken
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 kcalories, 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, cooked
2 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 kcalories, 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 Kcalorie 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 chloride
1 calcium carbonate tablets (400 mg calcium)
1/4 multiple vitamin-mineral tablet
1/10 tablet B complex vitamin-trace mineral

provides 297 kcalories, 16.3 g protein, 14.5 g fat
See 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

Chicken and Rice
Low Protein, Low phosphorus, Normal Potassium, Normal Sodium
Diet Providing 46.4 Grams Protein/1000 Kcalorie Diet

1/4 cup cooked chicken breast (72 grams)
1/2 ounce clams, canned, chopped in juice (14 grams)
1 cups cooked rice, white polished, long-grain (160 grams)
1 tablespoons chicken fat (14 grams)
1/8 teaspoon salt substitute-potassium chloride
1 calcium carbonate tablets (400 mg calcium)
1/4 multiple vitamin-mineral tablet
1/10 tablet B complex vitamin-trace mineral

provides 399 kcalories, 18.5 g protein, 14.7 g fat
See table for caloric needs of cats
provides phosphorus 43%, potassium 164%, sodium 124% 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 Sodium
Diet Providing 53 Grams Protein/1000 Kcalorie Diet

3 whites from whole chicken eggs, cooked
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 chloride
1 ½ calcium carbonate tablet (600 mg calcium)
1/4 multiple vitamin-mineral tablet
1/10 tablet B complex vitamin-trace mineral

provides 312 kcalories, 19.7 g protein, 13.8 g fat
See 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

Egg White and Rice
Low Protein, Low phosphorus, Normal Potassium, Normal Sodium
Diet Providing 46.6 Grams Protein/1000 Kcalorie Diet

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

provides 399 kcalories, 18.6 g protein, 13.9 g fat
See 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
Low Protein, Low phosphorus, Normal Potassium, Normal Sodium
Diet Providing 54.2 Grams Protein/1000 Kcalorie Diet

2 cooked whole eggs, chicken
1/2 ounce clams canned, chopped in juice (14 grams)
1 tablespoon chicken fat (14 grams)
1/8 teaspoon salt substitute-potassium chloride
1 calcium carbonate tablet (400 mg calcium)
1/4 multiple vitamin-mineral tablet
1/10 tablet B complex vitamin-trace mineral

provides 308 kcalories, 16.7 g protein, 25 g fat
See table for caloric needs of cats
provides phosphorus 89%, potassium 274%, sodium 673% of a cat's daily needs.
Bone meal need not be used in this diet to increase phosphorus content.

Eggs and Rice
Low Protein, Low phosphorus, Normal Potassium, Normal Sodium
Diet Providing 45.7 Grams Protein/1000 Kcalorie Diet

2 cooked whole eggs, chicken
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 chloride
1 calcium carbonate tablet (400 mg calcium)
1/4 multiple vitamin-mineral tablet
1/10 tablet B complex vitamin-trace mineral

provides 411 kcalories, 18.8 g protein, 25.2 g fat
See table for caloric needs of cats
provides 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 Sodium
Diet Providing 57.4 Grams Protein/1000 Kcalorie 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 tablet
1/10 tablet B complex vitamin-trace mineral

provides 453 kcalories, 26 g protein, 30.6 g fat
See table for caloric needs of cats
provides 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

Chicken and Potato
Low Protein, Low phosphorus, Normal Potassium, Normal Sodium
Diet Providing 46.2 Grams Protein/1000 Kcalorie Diet

1/3 cup cooked chicken breast (95 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 tablet
1/10 tablet B complex vitamin-trace mineral

provides 418 kcalories, 19.3 g protein, 29.9 g fat
See table for caloric needs of cats
provides phosphorus 47%, potassium 198%, sodium 172% 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

Beef and Rice
Low Protein, Low phosphorus, Normal Potassium, Normal Sodium
Diet Providing 56.8 Grams Protein/1000 Kcalorie Diet

4 ounces (raw weight) lean ground beef, cooked (114 grams)
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 1/2 calcium carbonate tablets (600 mg)
1/4 multiple vitamin-mineral tablet
1/10 tablet B complex vitamin-trace mineral

provides 443 kcalories, 25.2 g protein, 26.6 g fat
See table for caloric needs of cats
provides phosphorus 52%, potassium 123%, sodium 206% 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

Beef and Rice
Low Protein, Low phosphorus, Normal Potassium, Normal Sodium
Diet Providing 44.3 Grams Protein/1000 Kcalorie Diet

4 ounces (raw weight) lean ground beef, cooked (114 grams)
1/2 ounce clams canned, chopped in juice (14grams)
1/2 cups cooked rice, white polished, long-grain (80 grams)
2 tablespoon chicken fat (28 grams)
1 1/2 calcium carbonate tablets (600 mg)
1/4 multiple vitamin-mineral tablet
1/10 tablet B complex vitamin-trace mineral

provides 569 kcalories, 25.2 g protein, 40.5 g fat
See table for caloric needs of cats
provides phosphorus 45%, potassium 105%, sodium 175% of a cat's daily needs.
To feed this diet with a normal amount of phosphorus substitute bone 2 grams meal powder for the 1 1/2 calcium carbonate tablets.
Add 1/8 teaspoon potassium chloride to increase potassium content.

Beef
Low Protein, Low phosphorus, Normal Potassium, Normal Sodium
Diet Providing 55.3 Grams Protein/1000 Kcalorie Diet

4 ounces (raw weight) lean ground beef, cooked (114 grams)
1/2 ounce clams canned, chopped in juice (14 grams)
5 teaspoons chicken fat (24 grams)
1 calcium carbonate tablets (400 mg calcium)
1/4 multiple vitamin-mineral tablet
1/10 tablet B complex vitamin-trace mineral

provides 430 kcalories, 23.8 g protein, 35.8 g fat
See table for caloric needs of cats
provides phosphorus 50%, potassium 126%, sodium 234% 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 tablets.
Add 1/8 teaspoon potassium chloride to increase potassium content.

Beef and Potato
Low Protein, Low phosphorus, Normal Potassium, Normal Sodium
Diet Providing 46.7 Grams Protein/1000 Kcalorie Diet

4 ounces (raw weight) lean ground beef, cooked (114 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 (400 mg calcium)
1/4 multiple vitamin-mineral tablet
1/10 tablet B complex vitamin-trace mineral

provides 540 kcalories, 25.2 g protein, 40.5 g fat
See table for caloric needs of cats
provides phosphorus 46%, potassium 194%, sodium 185% 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.

Tuna and Rice
Low Protein, Low phosphorus, Normal Potassium, High Sodium
Diet Providing 53.4 Grams Protein/1000 Kcalorie Diet

3 ounces tuna, canned in water (86 grams)
1/2 ounce clams canned, chopped in juice (14 grams)
1/2 cups cooked rice, white polished, long-grain (80 grams)
2 tablespoons chicken fat (28 grams)
1/8 teaspoon salt substitute-potassium chloride
1 1/2 calcium carbonate tablets (600 mg calcium)
1/4 multiple vitamin-mineral tablet
1/10 tablet B complex vitamin-trace mineral

provides 468 kcalories, 25 g protein, 30 g fat
See table for caloric needs of cats
provides phosphorus 50%, potassium 190% of a cat's daily needs, sodium depends on using low salt tuna.
To feed this diet with a normal amount of phosphorus substitute 2 grams bone meal powder for the 1 1/2 calcium carbonate tablets

Tuna and Rice
Low Protein, Low phosphorus, Normal Potassium, High Sodium
Diet Providing 44.8 Grams Protein/1000 Kcalorie Diet

2 ounces tuna, canned in water (57 grams)
1/2 ounce clams canned, chopped in juice (14 grams)
1/3 cups cooked rice, white polished, long-grain (53 grams)
2 tablespoons chicken fat (28 grams)
1/8 teaspoon salt substitute-potassium chloride
1 calcium carbonate tablets (400 mg calcium)
1/4 multiple vitamin-mineral tablet
1/10 tablet B complex vitamin-trace mineral

provides 406 kcalories, 18.2 g protein, 29.6 g fat
See table for caloric needs of cats
provides phosphorus 46%, potassium 209% of a cat's daily needs, sodium depends on using low salt tuna.
To feed this diet with a normal amount of phosphorus substitute 2 grams bone meal powder for the 1 calcium carbonate tablet.

Patient Evaluation During Dietary Management

The evaluation of all patients is done by periodic blood chemistry measurements and any other appropriate testing. It is expected that abnormal blood values will improve or return to normal. After recovery it becomes important to modify dietary restrictions to provide an animal's nutritional needs. Without this monitoring it is possible that nutrient deficiency could develop. The owner-prepared diets offer more than one choice of special diet for disease conditions than are available from commercial pet food companies. An animal's specific needs can be met with owner-prepared diets. That might be possible if a commercial diet just happens to provide what is needed for recovery. With improvement some of the fat soluble vitamins can be given. It is not necessary to give them more than weekly or several times a month. The liver stores these vitamins and it takes months or years to deplete the the stores of vitamins A and D, ones that have the greatest potential for being toxic.

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.