What to feed a dog with kidney disease

The best-supported food for a dog with chronic kidney disease is a prescription kidney diet, chosen with your vet for your dog's stage and bloodwork. In studies, dogs with kidney disease fed these diets have tended to live longer and feel well for longer than dogs kept on regular adult food.

The second rule matters almost as much: the food only helps if your dog eats it. A dog that refuses its kidney diet and loses weight is worse off than one eating something less ideal, so a large part of feeding a dog with kidney disease is keeping the appetite going. For the condition itself, see our overview of kidney disease in senior dogs.

What makes a kidney diet a kidney diet

Prescription kidney diets (also called renal diets) differ from regular dog food in several ways at once. That combination is hard to copy by picking a different bag off the shelf.

• Restricted phosphorus. The most important change. More on this below.
• Moderate, high-quality protein. Less than regular adult food, from easily digested sources, so there is less waste for the kidneys to clear.
• Added omega-3 fatty acids. Usually from fish oil. They may help protect the kidney tissue that is still working.
• More moisture. In the canned versions, which helps a dog that is losing extra water in its urine.
• Plenty of calories in a small serving. Dogs with kidney disease often eat less, so each mouthful has to count.
• Other adjustments. Typically less sodium, added B vitamins, and ingredients that help balance acid in the blood.

Foods labeled "senior" are not kidney diets, and some contain more protein and phosphorus than regular adult food. Our guide to choosing a senior dog food covers healthy older dogs. Once kidney disease is diagnosed, the choice of food belongs with your vet.

Why phosphorus matters most

Healthy kidneys remove extra phosphorus from the blood. Damaged kidneys cannot keep up, so phosphorus builds. High phosphorus makes a dog feel unwell, upsets the balance of calcium and bone, and is linked with faster loss of the kidney function that is left.

Lowering phosphorus in the food is the part of a kidney diet with the strongest evidence behind it. Your vet tracks blood phosphorus at rechecks. If food alone does not keep it in the target range, they may add a phosphate binder, a medicine mixed into meals that stops some phosphorus from being absorbed. Which one and how much is your vet's decision, based on bloodwork.

Low protein dog food for kidney disease: how low?

Not as low as possible. The waste left over from digesting protein is a large part of what makes a dog with kidney disease feel nauseated, so moderating protein helps. Cut it too far and the dog loses muscle, gets weaker and copes worse.

Kidney diets settle on a moderate amount of high-quality protein. Dogs that are leaking protein into their urine may need a different balance, and dogs in the earliest stage may not need a full kidney diet yet. Your vet decides when to start, based on the stage. Our guide to dog kidney disease stages explains how staging works.

Wet or dry?

Either can work. Wet food has the advantage of carrying water with it, and dogs with kidney disease drink and urinate more and dehydrate easily. If your dog prefers dry, you can ask your vet about adding warm water to it or feeding a mix of both.

Whichever you feed, keep fresh water available at all times. Never limit water for a dog with kidney disease.

How to switch to a kidney diet

Go slowly. Mix a little of the new food into the old and shift the balance over a couple of weeks, or longer if your dog hesitates. A sudden swap is the most common reason dogs reject a kidney diet.

• Start when your dog feels reasonably well. A food first offered during nausea or a hospital stay can become a food the dog avoids for good.
• Do not hide pills in the kidney diet. Use something else your vet has approved, so the food stays trusted.
• If one diet is refused, ask your vet for another. Several prescription kidney diets exist, in different flavors and textures, and many dogs that refuse one accept another.

How to get a dog with kidney disease to eat

A poor appetite in kidney disease is usually nausea, not fussiness. Waste products that the kidneys no longer clear irritate the stomach and can cause mouth ulcers. So the first step is to tell your vet. Prescription anti-nausea medicine, stomach protectants and appetite stimulants often make more difference than anything you can do with the bowl.

Do not reach for human stomach remedies or painkillers on your own. Ibuprofen, naproxen, aspirin and acetaminophen can seriously harm or kill dogs, and some of them damage the kidneys directly. Nothing should be given unless your vet has specifically directed it.

Alongside the vet's treatment, these are the things that tend to help at home:

• Warm the food. Lukewarm food smells stronger, and smell drives appetite. Stir it well and check that it is not hot.
• Hand feed. Many dogs will eat from a hand or a spoon when they will not eat from a bowl.
• Offer smaller meals, more often. A large meal can be too much for a queasy stomach.
• Change the texture or flavor. Try a different prescription kidney diet, a stew instead of a loaf, or wet and dry mixed.
• Keep it fresh. Pick up food that has not been eaten and offer a fresh portion later, so stale food does not put your dog off.
• Ask about a topper. Your vet may approve a little of something tasty mixed in to get a meal started.
• Do not force it. Syringe feeding without your vet's guidance risks food going down the wrong way and can make a dog dread mealtimes.

If your dog still refuses the kidney diet, go back to your vet. They may agree on a fallback food or, for some dogs, suggest a feeding tube. Our article on why an old dog stops eating covers other causes worth ruling out, such as dental pain.

Treats for dogs with kidney disease

Treats should stay a small part of the day's food, and many commercial ones are high in phosphorus, protein and salt. The table is a general guide to which foods tend to sit at each end. Check anything on it with your vet first, because the right answer depends on your dog's bloodwork.

Homemade dog treats for kidney disease

The safest homemade treat is a single plain ingredient from the lower-phosphorus column, once your vet has cleared it for your dog. You can also ask your vet whether your dog's own prescription canned food can be sliced and baked into firmer treats, and whether a prescription kidney treat is available. Baked recipes built on flour, peanut butter, cheese or broth are harder to judge, so run those past your vet too.

Foods that are toxic to dogs

These are off the list for every dog, and some of them injure the kidneys directly:

• Grapes, raisins and currants
• Onions, garlic, chives and leeks, including powders in broths and baby food
• Xylitol, a sweetener also labeled birch sugar, found in some peanut butters and sugar-free foods
• Macadamia nuts
• Chocolate

Kidney diet recipes for dogs: why there is not one here

Many people search for homemade kidney diet recipes, and we are not going to give one. When veterinary nutritionists have analyzed kidney recipes published in books and online, most fell short on essential nutrients, and many did not control phosphorus the way a kidney diet needs to.

A general recipe also cannot know your dog. The right levels of protein, phosphorus and potassium depend on the stage of disease and on bloodwork that changes over time. A recipe that suits one dog can harm another.

Home cooking is still possible. It has to be formulated by a board-certified veterinary nutritionist for your dog's bloodwork, with the specific supplements they prescribe, and then adjusted as results change. Your vet can refer you, and many nutritionists work remotely alongside your own clinic. For general feeding principles in older pets, see our senior pet nutrition guide.

When to call the vet today

Call your vet or an emergency clinic now if your dog:

• Has eaten nothing for 24 hours, or far less than normal for two days
• Is vomiting repeatedly, or has blood in the vomit or black, tarry stools
• Has stopped drinking, or is producing very little or no urine
• Is very weak, wobbly, collapsed or hard to wake
• Is trembling, twitching or having a seizure
• May have eaten grapes, raisins, xylitol or any human medicine

This article is general educational information about feeding dogs with kidney disease, not veterinary advice. It does not replace a diet plan made for your dog, and it intentionally gives no recipes, amounts or doses. What your dog should eat, including any treats, supplements, phosphate binders or home-cooked food, should be decided with your veterinarian based on your dog's bloodwork and stage of disease.