Kidney disease can be influenced greatly by appropriate dietary management. Specially formulated diets can slow disease progression and significantly increase survival time. The team at Groves Veterinary Clinic provides guidelines on what elements should be restricted and supplemented if your pet is affected by kidney disease.

Dietary elements to restrict if your pet has kidney disease

Certain substances can cause further problems for pets affected by kidney disease and should be limited in your pet’s diet.

  • Phosphorus — The glomerular filtration rate (GFR) tests kidney function by estimating how much blood passes through the kidneys each minute. GFR is reduced in pets affected by kidney disease, resulting in decreased phosphorus excretion. Higher phosphorus levels in the bloodstream cause increased parathyroid hormone secretion, which results in calcium and phosphorus leaching from bone. The end result is soft tissue mineralization, progressive kidney damage, and bone loss. By restricting phosphorus consumption, these issues can be mitigated. 

The Association of American Feed Control Officials (AAFCO) requires minimum phosphorous levels of 1.4 mg/Mcal for dogs and 1.25 mg/Mcal for cats. Therefore, most over-the-counter diets are inappropriate for pets affected by kidney disease. Commercial kidney diets contain 0.48 to 1.2 g/Mcal phosphorus for dogs and 0.8 to 1.28 g/Mcal phosphorus for cats. At these low levels, phosphorus can still be problematic, and pets may need phosphate binders to further lower phosphorus levels. 

  • Protein — As protein is metabolized, nitrogenous waste is produced, and these products cannot be cleared efficiently when GFR is reduced in pets affected by kidney disease. As these substances build up in the bloodstream, they cause nausea, decreased appetite, and lethargy, and can also contribute to gastric ulceration, and reduce red blood cell lifespan. High protein levels entering the kidneys also can further damage kidney tissue. Protein should be reduced by maximizing protein quality without adding excess amounts that will be metabolized to toxins. Feeding high quality protein sources that contain well-balanced essential amino acids can lower overall protein content while meeting physiologic protein requirements. Most pets’ protein needs can be met by switching to a commercial kidney diet containing 12 percent to 15 percent protein for dogs and 20 percent to 27 percent protein for cats.
  • Sodium — High sodium levels can cause high blood pressure and worsen kidney damage, so low sodium diets are recommended in pets affected by kidney disease. Most commercial kidney diets have sodium concentrations above physiological requirements, but less than most over-the-counter diets.
  • Acidity — The normal kidney helps control acid-base balance by regulating hydrogen ion excretion and bicarbonate regeneration. Pets affected by kidney disease often become acidic, and need commercial kidney diets to counteract this issue. Most over-the-counter foods are acidifying, especially for cats, to help prevent struvite crystals in their urine.

Dietary supplements if your pet has kidney disease

  • Omega-3 fatty acids — Supplementing long chain omega-3 fatty acids from fish oil (eicosapentaenoic acid, EPA; and docosahexaenoic acid, DHA) may potentially protect the kidney. Some commercial kidney diets currently contain varied amounts of supplemental fish oil. A recommended dose is 300 mg total DHA and EPA per 10 pounds of body weight.
  • B vitamins — All pets require these water soluble vitamins to maintain numerous metabolic functions. Pets who have kidney disease have increased losses secondary to excessive urination. Most commercial kidney diets have supplemental B vitamins to account for this extra loss.
  • Potassium — Cats affected by kidney disease are more likely to have decreased potassium levels. Dogs can also have decreased potassium levels, but may have increased levels, especially if they are on particular medications, called ACE-inhibitors, to treat their kidney disease. Commercial kidney diets have wide ranges of potassium concentrations, and the correct food should be chosen based on your pet’s potassium levels. 

Any diet change should be accomplished gradually, over one to two weeks. Palatability enhancers, such as fish oil and homemade low sodium meat broths, can be used to tempt a skeptical pet. Treats high in protein, phosphorus, and sodium should be avoided. Most over-the-counter foods do not meet the requirements necessary for pets affected by kidney disease, but numerous commercially available prescription diets are available. Home-cooked diets can also be considered, but most online recipes are unbalanced and inappropriate for pets with kidney disease. You should consult a veterinary nutritionist before pursuing this option.

If your pet continues to refuse to eat and cannot maintain an appropriate body condition, a feeding tube can facilitate feeding. An esophagostomy tube can be used to administer food, water, and medication, to decrease stress associated with getting your pet to voluntarily eat or drink. This procedure should be performed before your pet becomes significantly debilitated to ensure the best outcome.

If your pet has kidney disease, modifying their diet can improve their well-being and prolong their life. If you would like to discuss dietary recommendations for your pet, do not hesitate to contact the team at Groves Veterinary Clinic.