TL;DR
The best food for a dog with kidney disease is a kidney (renal) diet: lower in phosphorus and sodium, with moderate amounts of high-quality protein, added omega-3 fatty acids from fish oil, and enough calories to keep weight and muscle on. This is one of the best-proven treatments in veterinary medicine. In a double-masked randomized trial of 38 dogs with chronic kidney disease, dogs fed a renal diet for up to two years had fewer uremic crises, a lower death rate and a slower loss of kidney function than dogs on a normal adult food. The ingredients behind that effect have their own evidence: in dogs with reduced kidney function, a lower-phosphorus diet slowed the monthly loss of kidney function from 11.1% to 2.6% and raised two-year survival from 33% to 75%, and fish oil omega-3s protected the kidneys while omega-6-rich oil made damage worse. The hardest part is often getting the dog to eat it, so switch gradually and keep calories up.
What a kidney diet changes
| Nutrient | Kidney diet | Why |
|---|---|---|
| Phosphorus | Restricted | Failing kidneys cannot clear it; high phosphorus speeds kidney damage |
| Protein | Moderate, high quality | Less waste for the kidneys while still supporting muscle |
| Omega-3 (EPA and DHA) | Added from fish oil | Protected kidney tissue in dog studies |
| Sodium | Reduced | Helps control blood pressure |
| Potassium and B vitamins | Added | Lost in larger amounts in dilute urine |
| Calories | Energy-dense | Many dogs with kidney disease eat less |
| Antioxidants and fiber | Often added | To reduce oxidative stress and support the gut |
The evidence
Renal diet vs normal food: the randomized trial
In the double-masked, randomized trial of 38 dogs with spontaneous chronic kidney failure, followed for up to 24 months:
- Dogs on the renal diet had fewer uremic crises (episodes of severe illness from toxin build-up).
- They had a lower death rate.
- Their kidney function declined more slowly on serial creatinine measurements.
- The benefit was seen in dogs with mild and moderate kidney failure.
Phosphorus restriction
In a long-term study of 24 dogs with greatly reduced kidney function:
| Diet | Monthly loss of kidney function | Survival at 24 months |
|---|---|---|
| Higher phosphorus and calcium | 11.1% per month | 33% |
| Lower phosphorus and calcium | 2.6% per month | 75% |
High phosphorus was linked to calcium deposits and scarring in the kidneys.
Fish oil omega-3s
In dogs with induced kidney disease fed different fats for 20 months:
- Fish oil (omega-3) lowered protein in the urine, creatinine, cholesterol and triglycerides, and reduced scarring and inflammation in kidney tissue.
- Safflower oil (omega-6) made kidney injury worse.
The authors concluded omega-3 was kidney-protective and omega-6 enhanced injury. That is why renal diets add fish oil.
When to start a kidney diet
Vets stage kidney disease with the IRIS system (stages 1 to 4). Renal diets are usually recommended once kidney disease is confirmed and staged, or earlier if there is persistent protein in the urine; the trial above showed benefit in mild and moderate disease. Starting earlier, before the dog feels unwell, makes the switch easier. See kidney disease in dogs.
Healthy senior dogs do not need a kidney diet or protein restriction. Older dogs need good protein to keep their muscle. See high-protein senior dog food.
Getting a dog with kidney disease to eat
Nausea and a poor appetite are common in kidney disease, and a dog that does not eat loses muscle fast. A 2021 review of kidney nutrition puts special weight on body weight, body condition and muscle condition and on managing poor appetite.
- Switch slowly over 1 to 3 weeks, mixing more of the new food each day.
- Try wet and dry versions and different brands; there are several prescription renal diets.
- Warm wet food slightly to boost smell.
- Feed small meals often.
- Ask about anti-nausea medicine and appetite stimulants if your dog is picky.
- Weigh your dog every few weeks.
If your dog refuses every renal diet, eating something is better than eating nothing. Ask your vet about phosphate binders mixed into the current food, or a home-cooked renal recipe made with a board-certified veterinary nutritionist.
See senior dog not eating and older dog losing weight.
Treats, supplements and water
- Avoid high-phosphorus treats such as jerky, cheese, bones and organ meats.
- Use low-phosphorus treats: small pieces of apple (no seeds), green beans, carrots or the renal diet itself.
- Keep fresh water available everywhere; dogs with kidney disease need extra water. See older dog drinking lots of water and hydration for senior dogs.
- Check every supplement with your vet. Some joint and multivitamin products add phosphorus, calcium or vitamin D. VCA advises caution with green-lipped mussel in dogs with kidney disease, so ask first. See green-lipped mussel side effects.
- Never give grapes or raisins.
FAQ
What should I feed a dog with kidney disease?
A veterinary renal diet, lower in phosphorus and sodium with moderate high-quality protein and added omega-3s. In a randomized trial it reduced uremic crises and deaths compared with a normal food.
Is a low-protein diet good for dogs with kidney disease?
Moderate, high-quality protein is the goal, combined with restricted phosphorus. Very low protein can cost muscle, and healthy senior dogs should not be protein-restricted.
When should a dog start a kidney diet?
Once your vet has confirmed and staged the disease, or earlier if there is persistent protein in the urine. Benefits were shown in dogs with mild and moderate kidney failure, so there is no reason to wait for late-stage signs.
What if my dog will not eat the renal diet?
Switch gradually, try other textures and brands, warm the food and ask about anti-nausea medicine. If it still refuses, your vet can suggest phosphate binders or a nutritionist-formulated home recipe.
Can I make homemade food for a dog with kidney disease?
Only with a recipe from a board-certified veterinary nutritionist. Home recipes from the internet are often unbalanced or too high in phosphorus.
References
- Jacob F, et al. Clinical evaluation of dietary modification for treatment of spontaneous chronic renal failure in dogs. Journal of the American Veterinary Medical Association. 2002. PMID: 11990962
- Brown SA, et al. Beneficial effects of dietary mineral restriction in dogs with marked reduction of functional renal mass. Journal of the American Society of Nephrology. 1991. PMID: 1768812
- Brown SA, et al. Beneficial effects of chronic administration of dietary omega-3 polyunsaturated fatty acids in dogs with renal insufficiency. Journal of Laboratory and Clinical Medicine. 1998. PMID: 9605110
- Parker VJ. Nutritional management for dogs and cats with chronic kidney disease. Veterinary Clinics of North America: Small Animal Practice. 2021. PMID: 33773648
For individual health questions, your veterinarian remains the best partner.
