Best Food for Dogs with Kidney Disease

The Role of Nutrition in Managing Chronic Kidney Disease in Dogs: Comprehensive Insights

Summary

Chronic kidney disease (CKD) is a serious health issue affecting both humans and dogs, characterised by a gradual decline in kidney function. Nutrition plays a crucial role in managing CKD, with dietary adjustments helping to slow disease progression and improve quality of life. This article explores the impact of protein, fruits, vegetables, dietary fibre, salt, omega-3, and probiotics on kidney health in dogs, drawing on extensive human research. It also highlights the importance of medical nutrition therapy and the role of veterinary nutritionists in creating effective dietary plans for dogs with CKD.

Table of Contents

• Introduction
• The Kidney’s Role in the Body
• Impact of Dietary Factors on Kidney Disease Progression
  • Protein and Renal Function
  • Fruits and Vegetables
  • Dietary Fibre
  • Salt
  • Impact of Omega-3 on Kidney Disease
  • Probiotics and Postbiotics for Kidney Disease
• Medical Nutrition Therapy
  • Protein Restriction
  • Phosphate
  • Dietary Fat
  • Plant-Based vs. Animal Diets in Treating CKD
  • Nutritional Adequacy and Protein Quality
  • Impact on CKD Progression and Complications
  • Whole Food Plant-Based Diet
• The Role of a Veterinary Nutritionist
• FAQ – Kidney Disease in Dogs
  • What is Chronic Kidney Disease in Dogs?
  • What are the Symptoms of Kidney Disease in Dogs?
  • What are the Stages of Kidney Disease in Dogs?
  • What are the Best Foods for Dogs with Kidney Disease?
  • What Foods Should Dogs with Kidney Disease Avoid?
  • What are the Most Important Dietary Considerations for Dogs with Kidney Disease?
  • Is Salt Bad for Dogs with Kidney Disease?
  • Is Phosphorus Bad for Dogs with Kidney Disease?
• Conclusion

Introduction

Chronic kidney disease (CKD) is a prevalent condition affecting both humans and dogs, characterised by a gradual loss of kidney function over time. In humans, CKD affects more than 10% of the global population, driven by factors such as obesity, hypertension, and diabetes. Similar trends are observed in the canine population, where CKD is a significant health issue, affecting an estimated 5-10%. (1, 2) Nutritional management has emerged as a crucial component in preventing and mitigating CKD. This article explores the role of nutrition in managing CKD in dogs, drawing on insights from extensive human research.

The Kidney’s Role in the Body

The kidneys are vital organs responsible for filtering waste products, excess substances, and fluids from the blood to form urine. Each kidney contains approximately 400,000 nephrons, the functional units that filter blood. Key functions of the kidneys include:

• Filtration: Removal of waste products and excess substances from the blood.
• Reabsorption: Returning essential substances like glucose, amino acids, and electrolytes to the bloodstream.
• Secretion: Expelling waste products and toxins from the blood into the urine.
• Regulation: Maintaining fluid and electrolyte balance, blood pressure, and acid-base balance.
• Hormone Production: Producing hormones like erythropoietin (stimulates red blood cell production) and renin (regulates blood pressure).

When the kidneys’ function declines, waste products and excess substances build up in the body, leading to various health issues.

Impact of Dietary Factors on Kidney Disease Progression

Protein and Renal Function

High protein intake, especially from animal sources, can exacerbate CKD by increasing renal blood flow and glomerular filtration rate (GFR), (3) leading to glomerular hyperfiltration and potential injury. Excessive protein consumption interferes with the kidney’s ability to autoregulate blood flow, increasing intracapillary pressure and leading to nephron damage. High protein diets are also associated with increased levels of advanced glycation end products (AGEs), which contribute to podocyte apoptosis and glomerular scarring.

For dogs with CKD, reducing protein intake can lower the workload on the kidneys and help manage the disease. Recommended protein levels vary based on the stage of CKD, with lower amounts suggested for advanced stages to reduce kidney strain. Protein restriction, particularly from animal sources, has been shown to slow the progression of CKD in dogs by reducing proteinuria and improving renal function. (4, 5,)

Fruits and Vegetables for Kidney Disease

Including fruits and vegetables in a dog’s diet can significantly lower net endogenous acid production, reducing the renal workload. Diets rich in fruits and vegetables, similar to the DASH diet for humans, have been associated with lower CKD risk and progression. The alkalinising effect of these foods helps maintain acid-base balance, which is crucial for kidney health. (7, 8, 9)

In addition to this alkalinising effect, quercetin, a flavonoid found in apples, berries, citrus fruits, kale, spinach, broccoli, green tea, red wine, and herbs like parsley and sage, has been shown to have significant benefits for CKD. Note: Although quercetin is found in these foods, onions and red wine, they should not be fed to dogs as they are toxic. (10, 11, 12, 13)

Dietary Fibre

High-fibre diets are beneficial in reducing inflammation, a key factor in CKD progression. Fibre promotes the growth of beneficial gut bacteria, reducing gut-derived uremic toxins such as trimethylamine N-oxide (TMAO), which accelerate CKD progression. Additionally, fibre helps in stool excretion, facilitating urea and potassium removal, which is crucial for CKD management in dogs.

Salt

High sodium intake exacerbates CKD by increasing blood pressure, causing volume expansion, and inducing oxidative stress in the kidneys. Reducing salt intake lowers blood pressure and urine albumin excretion, crucial for slowing CKD progression. The Western diet’s high salt content is detrimental to kidney health, making salt reduction a key dietary intervention. (14)

Impact of Omega-3 on Kidney Disease

Omega-3 polyunsaturated fatty acids (PUFAs) have anti-inflammatory properties that can be beneficial for kidney health. Research has shown that omega-3 supplementation can decrease mesangial cell proliferation and matrix production, enhance endothelial function, and lower blood pressure. In dogs with CKD, omega-3 PUFAs can help slow the progression of kidney disease by reducing proteinuria and inflammation. Including sources of omega-3, such as algal oil or salmon oil, in a dog’s diet can provide these protective effects, potentially improving renal function and overall health outcomes.

Probiotics and Postbiotics for Kidney Disease

Probiotics and postbiotics can play a significant role in managing CKD by promoting a healthy gut microbiome and reducing systemic inflammation. Probiotics are live beneficial bacteria that, when administered in adequate amounts, confer health benefits. Postbiotics are non-viable bacterial products or metabolic by-products that exert beneficial effects on the host. In dogs with CKD, probiotics can help decrease the production of gut-derived uremic toxins like TMAO and p-cresyl sulphate, which contribute to CKD progression. Incorporating probiotics into the diet can enhance gut health, reduce inflammation, and improve kidney function. Postbiotics, through their anti-inflammatory and antioxidant properties, can further support kidney health by mitigating oxidative stress and inflammation in dogs.

Medical Nutrition Therapy

Protein Restriction

For dogs with CKD, protein restriction is crucial to slow disease progression. Guidelines suggest moderate protein restriction (35 g/1,000kcal) for non-diabetic CKD patients. Very-low-protein diets (VLPD), supplemented with essential amino acids, are particularly beneficial in advanced CKD stages but require careful monitoring to prevent malnutrition.

Phosphate

Phosphate intake from animal protein sources is higher due to better absorption compared to plant sources. High dietary phosphate intake can exacerbate CKD progression by causing tubular injury and nephrocalcinosis. Reducing phosphate intake, especially from inorganic sources, is beneficial for CKD management in dogs. Recommended levels are 750 mg per 1000 kcal.

Dietary Fat

While saturated fats are linked to increased urine albumin excretion and higher cardiovascular risk, the role of dietary fats in CKD progression is less clear. Diets rich in omega-3 polyunsaturated fatty acids (PUFAs) may benefit CKD patients by reducing inflammation and improving endothelial function.

Whole Food Plant-Based Diet

A whole food plant-based (WFPB) diet is associated with numerous health benefits, including reduced risk of diabetes and cardiovascular disease, both of which are risk factors for CKD. This diet emphasises fruits, vegetables, whole grains, nuts, and seeds while excluding processed and refined foods. WFPB diets are high in fibre, which promotes gut health and reduces inflammation, and low in protein, which reduces kidney workload. However, careful planning is needed to ensure adequate nutrient intake, particularly for protein and vitamin B12.

Plant-Based vs. Animal Diets in the Treatment of Chronic Kidney Disease

Nutritional Adequacy and Protein Quality

Plant-based diets, such as vegetarian and vegan diets, are increasingly adopted by CKD patients due to their lower protein content and beneficial effects on hyperfiltration. Historically, plant-based diets were considered nutritionally inadequate due to potential deficits in essential amino acids. However, balanced vegetarian and vegan dog foods can provide comparable nutritional value to animal-based diets when correctly formulated.

The Protein Digestibility Corrected Amino Acid Score (PDCAAS) and the Digestible Indispensable Amino Acid Score (DIAAS) are tools used to measure protein quality. Although animal proteins typically score higher, diversified vegetarian and vegan diets can achieve equivalent nutritional benefits.

Impact on CKD Progression and Complications

Vegetarian and vegan diets generate fewer uremic toxins, support nitrogen balance, and promote short-chain fatty acid production, enhancing the intestinal barrier and reducing inflammation. These diets are also pH-neutral, aiding in acid-base balance and reducing metabolic acidosis, which is prevalent in meat-heavy diets.

Phosphorus content in plant proteins is less bioavailable due to its storage in non-absorbable phytate form, which is advantageous for CKD patients. This reduces the risk of mineral and bone disorders, secondary hyperparathyroidism, and cardiovascular issues associated with high animal protein intake.

Plant-based diets also contribute to better blood pressure control, lipid metabolism, and gut microbiota health. Lower levels of L-carnitine in vegetarian diets reduce the production of trimethylamine N-oxide (TMAO), a compound linked to increased cardiovascular disease risk.

Low-protein diets, particularly those based on plant proteins, are effective and nutritionally safe for managing CKD. These diets can slow disease progression, improve patient survival, and address metabolic disturbances. Vegetarian and vegan LPDs offer superior benefits over mixed diets, highlighting the potential of plant-based nutrition in CKD treatment.

The Role of a Veterinary Nutritionist

Dietary education and counselling by a veterinary nutritionist are essential for managing CKD in dogs. Veterinary nutritionists provide individualised dietary plans, monitor nutritional status, and ensure compliance with dietary recommendations. Medical nutrition therapy (MNT) can slow CKD progression, prevent comorbidities, and improve the quality of life for dogs with CKD.

When selecting a food for a dog with kidney disease it is important to consult with either a board-certified  veterinary canine nutritionist (preferable) or a vet to identify an acceptable protein level for the dog, understanding the severity of their CKD. As outlined above, the appropriate level of protein (or protein restriction) recommended will depend on the stage of CKD the dog is suffering from.

Protein restriction as a dietary management strategy for CKD has become increasingly controversial. Some argue that, in an effort to retain muscle mass and increase diet palatability, dogs with kidney disease should not be placed on a low-protein diet, while others cite research suggesting that lower-protein diets, in combination with other nutrient modifications, reduce morbidity and prolong lifespan. ^{(15, 16, 17)}

There is still much to learn about the nutritional needs of dogs with CKD. While the combination of moderately low protein, low phosphorus, moderate sodium, and moderately high potassium and EPA/DHA is proven to reduce uremia and extend the lifespan of dogs with CKD, controversy remains regarding the optimal dietary protein concentration for dogs with this disease. Dogs with early stages of CKD will likely tolerate less protein restriction than dogs with severe azotaemia. In addition, hyporexia induced by CKD may play a more important role in muscle wasting seen in patients eating a therapeutic renal diet.

FAQ – Kidney Disease in Dogs

What is Chronic Kidney Disease in Dogs?

Chronic Kidney Disease (CKD) in dogs is a progressive condition characterised by the gradual loss of kidney function over time. The kidneys play a vital role in filtering waste products, excess substances, and fluids from the blood to form urine. In CKD, the kidneys become less efficient at performing these functions, leading to an accumulation of toxins and waste products in the body. This condition can lead to various health issues, including electrolyte imbalances, hypertension, and anaemia.

What are the Symptoms of Kidney Disease in Dogs?

Symptoms of kidney disease in dogs can vary depending on the stage of the disease but commonly include:

• Increased thirst and urination
• Decreased appetite and weight loss
• Vomiting and diarrhoea
• Lethargy and weakness
• Bad breath (uremic odour)
• Mouth ulcers
• Poor coat condition
• Pale gums
• High blood pressure
• Dehydration

What are the Stages of Kidney Disease in Dogs?

The stages of kidney disease in dogs are typically classified based on the International Renal Interest Society (IRIS) staging system, which considers blood creatinine levels, urine protein levels, and blood pressure. The stages are:

• Stage 1: Early disease with normal or mildly elevated blood creatinine levels and no clinical signs.
• Stage 2: Mild renal insufficiency with moderate elevations in blood creatinine levels and minimal clinical signs.
• Stage 3: Moderate renal insufficiency with higher blood creatinine levels and noticeable clinical signs.
• Stage 4: Severe renal failure with very high blood creatinine levels and significant clinical signs.

What are the Best Foods for Dogs with Kidney Disease?

The best foods for dogs with kidney disease include those that are specifically formulated to support kidney function and manage the progression of the disease. Key features of such diets include:

• Low protein: To reduce the workload on the kidneys.
• High-quality protein: To ensure essential amino acids are provided.
• Low phosphorus: To prevent further kidney damage.
• Low sodium: To help control blood pressure.
• Increased omega-3 fatty acids: To reduce inflammation.
• Added antioxidants: To combat oxidative stress. Examples of suitable foods include prescription renal diets available from veterinarians and commercial dog foods designed for kidney support.

What Foods Should Dogs with Kidney Disease Avoid?

Dogs with kidney disease should avoid foods that can exacerbate their condition, including:

• High-protein foods: Such as red meat, chicken, and fish (especially raw or undercooked).
• High-phosphorus foods: Including dairy products, egg yolks, and organ meats.
• High-sodium foods: Such as processed snacks, salty treats, and human foods like chips and pretzels.
• Foods with artificial additives and preservatives: These can be harder for compromised kidneys to process.
• Grapes and raisins: Which are toxic to dogs and can cause kidney damage.

What are the Most Important Dietary Considerations for Dogs with Kidney Disease?

The most important dietary considerations for dogs with kidney disease are:

• Protein restriction: To decrease the production of waste products that kidneys need to filter.
• Phosphorus restriction: To reduce the risk of mineral imbalances and further kidney damage.
• Sodium restriction: To manage blood pressure and fluid balance.
• Increased fibre: To help remove waste products through the digestive tract.
• Omega-3 fatty acids: To reduce inflammation and support overall kidney health.
• Hydration: Ensuring the dog has access to fresh water at all times to support kidney function and prevent dehydration.

Is Salt Bad for Dogs with Kidney Disease?

Yes, salt (sodium) is bad for dogs with kidney disease. High sodium intake can lead to increased blood pressure and fluid retention, both of which can strain the kidneys and exacerbate CKD symptoms. Reducing salt intake is crucial for managing the disease and preventing complications.

Is Phosphorus Bad for Dogs with Kidney Disease?

Yes, phosphorus can be bad for dogs with kidney disease. High phosphorus levels can cause further kidney damage and contribute to the progression of CKD. It can also lead to secondary hyperparathyroidism, a condition that results in bone demineralisation and further health issues. Therefore, it’s important to limit phosphorus intake in dogs with CKD through dietary management to a level of 0.5-0.8g/1000kcal of food.

Conclusion

Chronic kidney disease is a significant health concern in dogs, similar to humans. Medical nutrition therapy, focusing on protein restriction, increased intake of fruits and vegetables, reduced salt intake, omega-3 supplementation, and the use of probiotics, is crucial for managing CKD. Guidance from a veterinary nutritionist is essential for creating and maintaining effective dietary plans. Further research is needed to refine dietary recommendations and improve owner adherence, ultimately reducing the burden of CKD in dogs. By addressing dietary factors, veterinary care providers can improve the quality of life and prognosis for dogs with CKD, making nutrition a cornerstone of CKD management.

Bonza Superfoods and Ancient Grains plant-based, vegan dog food has been formulated to be gentle on your dog’s kidneys.

It has a moderate level of protein delivered by a carefully selected blend of plant-based proteins including peas, chickpeas, potato, sweet potato, fava beans, oats and yeast. The blend contains the correct balance of all the amino acids essential for your dog’s health.

The formula has very low levels of saturated fats but includes healthy polyunsaturated fats from rapeseed oil, algal oil extract and coconut oil.

The food also includes the very best prebiotic fibre sources (chicory root/inulin, Baobab and Yucca Schidigera extract and Spirulina), and clinically researched probiotic, Calsporin®, and postbiotic, TruPet® as well as DHAgold®, an exceptional source of Omega-3 with EPA, DHA and DPA.

Finally the food contains PhytoPlus®, a proprietary blend of natural plant-based phytonutrients formulated to protect your dog from inflammation and oxidative stress.

Bonza is the only vegan dog food that contains Omega-3 with EPA, DHA and DPA, prebiotics, probiotics and postbiotics which together contribute to supporting your dog’s fight against chronic kidney disease.