Diet for Dogs with Kidney Disease (CKD)

Updated September 2025 by Kristina Johansen, PGCert

Dietary management is one of the most effective tools we have for supporting dogs with kidney disease and slowing its progression. In fact, a 2020 study showed that those fed therapeutic kidney diets not only lived longer but also took much longer to develop severe symptoms compared with dogs on regular diets. In this guide, we’ll cover:

• The role and function of your dog’s kidneys
• Recognising the signs and symptoms of kidney failure
• Disease stages
• Dietary management (protein, phosphorus, and more)
• Why hydration matters
• FAQs on kidney disease in dogs

Let’s start with some basics.

Acute vs. Chronic Kidney Disease in Dogs: What’s the Difference?

There are two main types of kidney disease in dogs: acute and chronic. Acute kidney disease (or acute kidney injury, AKI) usually develops suddenly and can often be reversed. Chronic kidney disease (CKD), on the other hand, is a gradual and progressive loss of kidney function that takes place over months or even years.

Because acute and chronic kidney disease differ in both treatment and prognosis, this blog will focus on chronic kidney disease in dogs rather than acute kidney disease.

What Do My Dog’s Kidneys Do?

The main role of your dog’s kidneys is to filter waste products from the blood via urine. These waste products include old cells, the digestive process (foods), medications, and even poisons.

Over 1 million tiny tubes per kidney, called nephrons, perform the filtering. As blood passes from the capillaries through the nephrons, essential chemicals and molecules are kept, while waste products are removed and passed into urine collecting tubes. They are then expelled from your dog’s body with water as urine.

Filtering blood isn’t all these small but complex organs do. Your dog’s kidneys also help regulate:

• The amount of water in the blood
• Urine production
• Potassium and sodium levels.

And on top of all this, the kidneys produce three important hormones:

• Calcitriol, a form of vitamin D that helps calcium absorption, and in return, keeps bones healthy
• Erythropoietin, which tells the bone marrow to produce red blood cells
• Renin, which  helps regulate blood pressure

Given their wide range of essential functions, it’s therefore unsurprising that if the kidneys become damaged or compromised, it can lead to serious health issues.

What Are the Early Signs of Kidney Disease in Dogs?

There are several signs and symptoms of kidney disease to look out for in your dog. These may include:

• Increase thirst
• Increased urination
• Vomiting
• Diarrhoea
• Blood in the urine
• Lack of appetite and weight loss

Most of these signs aren’t specific to kidney disease, and symptoms can vary from dog to dog. This is why it’s so important to know what’s normal for your dog. If you notice anything unusual in their behaviour or habits, contact your vet straight away.

On physical examination, your vet may also identify other signs of kidney failure, such as:

• Pale gums (caused by anaemia)
• Ulcers on the tongue, gums, or inside the cheek
• A swollen abdomen or limbs due to fluid build-up

My Dog Has Been Diagnosed with Kidney Disease – What Should I Do Now?

It can be very worrying to hear that your dog has been diagnosed with kidney disease. However, please take some comfort in knowing that a carefully considered diet is key and can significantly improve your dog’s quality of life and longevity.

To illustrate just how crucial dietary intervention is, take a look at these numbers from one of my clients before and six weeks after implementing a dietary change:

Dietary Changes

Before we dive in, it’s important to note that kidney disease changes over time, so nutritional needs aren’t fixed. Diets should be tailored to each dog and adjusted as the disease progresses.

• In earlier stages (stage II and early stage III), the main aim is to slow the disease down and protect kidney function for as long as possible.
• In later stages (advanced stage III and stage IV), the focus shifts towards comfort and quality of life by easing symptoms linked to the build-up of toxins.

Protein

There’s a lot of debate about if, and when, protein should be restricted in dogs with kidney disease. Traditionally, the standard approach was to restrict dietary protein, and many vets still recommend this today. The idea behind this is simple:

• When protein is broken down, it produces waste products such as urea.
• In healthy dogs, the kidneys filter these wastes out efficiently.
• In dogs with kidney disease, the kidneys can’t cope as well, and waste builds up in the blood.
• This build-up can cause symptoms such as nausea, vomiting, loss of appetite, and fatigue.
• By reducing protein, we can ease this strain and help manage symptoms, particularly in the later stages of the disease.

However, newer research shows the story isn’t so simple. Dogs also need enough protein to maintain muscle, and being underweight or losing lean body mass can shorten survival. This means the ‘right’ protein level often depends on your dog’s condition, body score, and whether protein is leaking into the urine (proteinuria).

So, while protein still needs to be lower than a healthy dog’s diet, terms like ‘reduced’ and ‘restricted’ are all relative.

Where does this leave us?

• In the early stages of CKD, the focus is less on cutting protein and more on slowing disease progression by controlling phosphorus and managing proteinuria (protein leakage into the urine).
• In the later stages, when uremic symptoms become more prominent, a modest reduction in protein can help ease the burden on the kidneys and improve quality of life.

The importance of high-quality protein

It’s not just about protein intake. The quality of that protein is key. High-quality protein is important because it:

• Provides the body with the maximum benefit from the protein consumed
• Helps reduce unnecessary stress on the kidneys

That’s why it’s essential to consider something called the Biological Value (BV) when choosing the protein source. Biological Value is a ‘rating system’ for protein quality. It measures how well and efficiently a protein can be absorbed and used by your dog’s body. The higher the BV, the more effectively your dog can use the protein and the less waste the kidneys have to eliminate.

For example, eggs have a very high BV, nearly 100, meaning almost all the protein in eggs can be efficiently used by the body. Other good sources of high-quality protein include meat, dairy products, fish, and poultry.

It’s important to remember that even when using high-quality protein sources, such as eggs, the overall protein level and other nutrients still need to be considered. For example, feeding too many eggs can cause the dietary phosphorus level to be too high. The key goal should always be to prioritise overall nutritional balance.

Phosphorus

The primary nutrient of concern in dogs with kidney disease is dietary phosphorus. Here’s why: when the kidneys aren’t working properly, they can’t eliminate excess phosphorus in the urine. This causes phosphorus levels in the blood to rise, which upsets the delicate balance with calcium and triggers a cascade of problems in your dog’s body. It’s somewhat complicated, but I’ve tried to simplify it in this blog:

Calcium and Phosphorus Balance in Dogs with Kidney Disease

The bottom line is that while phosphorus is an essential nutrient in any dog’s diet, strong evidence shows that restricting it in dogs with kidney disease helps protect kidney function and can improve survival.

Again, ‘restricted’ is a relative term. Your dog’s phosphorus needs will depend on their kidney function. Ideally, phosphorus should be adjusted in line with creatinine and blood phosphorus results.

Foods particularly high in phosphorus include raw bones, dairy products, organ meats, and egg yolks. This doesn’t mean these foods must be avoided completely; the goal is to restrict phosphorus, not remove it.

So, to wrap up on protein and phosphorus: both are important, but they need to be carefully balanced – ensuring your dog gets enough high-quality protein for their needs while keeping phosphorus intake under control. If you’re feeding a commercial food and would like to compare protein and phosphorus levels between diets, you can use my Nutrient Calculator.

Sodium (aka salt)

When it comes to sodium, there are clear benefits to restricting it in the diets of people with kidney disease, as it’s been shown to decrease arterial hypertension.

However, there isn’t the same evidence to show that reducing sodium below the NRC-recommended requirement benefits dogs with kidney failure. The role sodium plays in kidney disease in dogs is not fully understood. By and large, it’s recommended that sodium levels should only be restricted moderately. This is because while excessive sodium levels can be detrimental, so can restriction. For those feeding home-prepared diets, this is usually less of a concern, as fresh foods naturally contain very little salt. You can read more about salt and your dog here:

Is Salt Bad for Dogs?

Omega-3 fatty acids

Omega-3 fatty acids can help slow the decline in kidney function by reducing inflammation and supporting healthier blood flow within the kidneys. For this reason, I always recommend incorporating omega-3s into the diet of dogs with kidney disease. The key ones to look for are EPA and DHA, the active forms your dog’s body needs. These can be provided through supplements such as fish body oil (but not cod liver oil) or by offering oily fish like fresh mackerel or sardines in your dog’s meals. To learn more about fish oil, including my go-to brands for good EPA/DHA levels, you can read more here:

How to Choose the Best Fish Oil for Your Dog.

Antioxidants

Research has shown that dogs with kidney disease experience higher levels of oxidative stress compared to healthy dogs. This is where antioxidants come in – they help control the damage caused by these free radicals.

Think of your dog’s body as a garden. Free radicals are like weeds that spread quickly, while antioxidants are the gardeners who keep them under control so the garden stays healthy. In dogs with kidney disease, more weeds (free radicals) grow, but there are fewer gardeners (antioxidants) to manage them. This imbalance puts extra stress on the body and contributes to disease progression. Adding antioxidants to your dog’s diet is like bringing in more gardeners to restore balance and slow the progression of kidney disease.

If you’d like to learn more about the importance of antioxidants and how to choose antioxidant-rich foods for your dog, you can read more here:

The Importance of Antioxidants for Dogs

Water

In chronic kidney disease, the kidneys lose their ability to concentrate urine, so more water is needed to flush out toxins. This causes dogs to produce larger volumes of dilute urine, and because they lose so much fluid, they then drink more to compensate. Ensuring your dog stays hydrated is therefore crucial for supporting kidney health.

Water needs can be met both through drinking and from the water naturally present in food. Dry dog food typically contains only 8–10% water, while canned food is about 75%. Fresh foods vary widely: for example, a cucumber is around 96% water, while a boiled egg is about 75%.

If your dog is reluctant to drink enough, you can make water more appealing by adding a splash of flavour. Try:

• Meat or vegetable broth
• Canned tuna or salmon water
• Watermelon Juice
• Coconut Water

Other simple strategies include soaking kibble, adding extra water to home-cooked meals, offering smaller meals more often, and placing multiple bowls of fresh water around the house so it’s always easy for your dog to drink.

Key Takeaways

Managing chronic kidney disease in dogs may seem overwhelming at first. However, with a good understanding of your dog’s dietary needs, you can significantly enhance the quality of life and longevity.

Key nutritional goals:

• Opt for a high-moisture diet to support hydration
• Restrict phosphorus, the most essential nutrient, to control.
• Provide moderate, high-quality protein (not too high, not too low)
• Add EPA/DHA (omega-3s) and antioxidant-rich foods to slow progression
• Adjust diet as the disease stage changes

FAQs on Kidney Disease in Dogs

We have reached the end of the blog. I hope the information has helped you better understand how to manage your dog’s kidney disease successfully. If you’d like quick answers to the most common questions about kidney disease, take a look at my FAQ page: Kidney Disease in Dogs: FAQs. It’s a useful companion to this article and covers many of the everyday questions owners have.

If you have any further questions or need help, don’t hesitate to contact me. Your feedback and suggestions are always welcome. To learn more about my approach and credentials, please visit my ‘About Page‘.

Meet Pickles

Before you go, I would like to introduce you to Pickles and share this lovely message I received from her owner.

“Pickles was diagnosed with CKD two years ago and recently the disease has started progressing. With a change of diet, within two weeks, I have a dog who is eating again, has no tummy pain, is sleeping through the night and is as regular as clockwork!!! She is also loving life again; chasing squirrels like there is no tomorrow, not bad for an old lady of 13 years, let alone one with CKD!

The transformation in just two weeks is unbelievable. Thank you again Kristina and I sincerely look forward to working with you to give my beloved Pickles the best quality of life, for as long as she has on earth.”

If you would like a deeper understanding of Chronic Kidney Disease in dogs and nutritional management, I have written a comprehensive eBook on the subject. The eBook expands on the information in this blog, providing deeper knowledge, practical advice, treat recipes and additional resources. You can find the book here:

Nutritional Management of CKD in Dogs

About the author:

Kristina Johansen, PGCert, MSc Animal Nutrition (cand.) is a pet nutritionist with over 15 years of experience. She specialises in home-prepared dog diets that meet NRC guidelines. Learn more →

Disclaimer: The information provided in this blog is meant for informational and educational purposes only. Please don’t try to create or modify your dog’s diet based on the information provided. Diet formulation for dogs with health concerns is complex. If you’re considering a homemade diet for your dog, please ensure it is formulated by a qualified dog nutritionist.

Diet & Health Advice

If your dog has kidney disease and you would like to feed a homemade diet, please email me. I’ll be happy to help.

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