Raw Diet vs. Kibble: Hydration for Kidney Health

Kristina Voltin
Jul 12
11 min read

Updated: Nov 21

Want to protect your dog’s kidneys? It starts with hydration. Dogs need water to keep their kidneys functioning properly, and diet plays a huge role in how much hydration they get. Raw diets, with 70–75% moisture, naturally support hydration and kidney health. In contrast, kibble contains just 6–10% moisture, often leading to dehydration and added strain on the kidneys.

Key takeaways:

Raw diets: High moisture, better protein quality, fewer additives, and reduced kidney strain.
Kibble: Low moisture, higher sodium and phosphorus, and synthetic additives that increase kidney workload.

For dogs with kidney concerns, switching to a moisture-rich diet like freeze-dried raw food (when rehydrated) can ease kidney stress and improve overall health. Always consult your vet for tailored advice.

Quick Comparison

Factor	Raw Diet (Rehydrated)	Kibble
Moisture Content	70–75%	6–10%
Protein Quality	High-quality	Lower-quality
Additives	Minimal	Common
Sodium & Phosphorus	Controlled levels	Often higher
Kidney Workload	Reduced	Increased

Hydration is vital for kidney health. Choosing the right diet can make all the difference.

Raw Diets: High Moisture Content for Better Hydration

Moisture Levels in Raw Diets

Raw diets naturally provide high moisture levels, which play a key role in keeping dogs hydrated and supporting kidney health [4]. This hydration benefit mirrors the ancestral diet of dogs, where moisture-rich foods were the norm. The contrast between raw and processed foods is striking - while raw, meat-based diets offer hydration alongside nutrition, processed options often lack this vital moisture. For example, muscle meat is composed of about 76% water, making it an excellent source of hydration [6]. Proper hydration helps flush toxins from the kidneys, prevents the formation of stones, and reduces the strain on these vital organs [4]. Additionally, high-moisture foods are easier for dogs to digest and absorb, further lightening the workload on the kidneys. But hydration is only part of the equation - ingredient quality also plays a major role.

Quality Ingredients and Kidney Support

Beyond hydration, raw diets stand out for their use of high-quality ingredients that directly benefit kidney health. These diets provide superior protein sources, which are easier for dogs with kidney challenges to process [7]. Proteins like eggs and raw meat generate less nitrogen waste during digestion, reducing the strain on the kidneys compared to the lower-quality proteins often found in kibble [7].

Raw diets also avoid problematic additives commonly found in processed foods, such as synthetic vitamins and minerals that can be tough for kidneys to handle [7]. Many raw diets are grain-free, which may help minimize inflammation, offering additional support for kidney function. For dogs dealing with chronic kidney disease, raw diets can be tailored to include lower phosphorus levels, a critical factor in managing the condition [7].

Loyal Saints Freeze-Dried Raw Food Benefits

Loyal Saints provides a practical way for pet owners to deliver the hydration and nutritional benefits of raw feeding. Their freeze-dried raw dog food offers the convenience of a shelf-stable product while retaining the hydration potential of raw diets. When rehydrated, this food delivers the same high moisture content that supports kidney health, paired with human-grade, all-natural ingredients.

Proper hydration doesn't just aid kidney function; it also promotes healthy skin and a shiny coat by nourishing cells from the inside out [5]. Loyal Saints' recipes, approved by veterinarians, ensure balanced nutrition without the additives or fillers that can burden kidney function. With high-quality protein sources, their food produces less nitrogen waste, making it easier on the kidneys. For dogs with specific kidney concerns, pet owners can add extra water to the freeze-dried food, tailoring hydration to meet their dog's unique needs [7].

Kibble and Hydration Problems

Low Moisture Content in Kibble

When it comes to hydration, kibble presents a unique challenge for dogs and places extra strain on their kidneys. Unlike fresh foods, which typically contain 60–75% moisture, dry kibble only has about 5–10%. This lack of natural hydration is a direct result of the manufacturing process, which removes moisture from the ingredients. As a result, dogs must rely on their own body fluids during digestion to compensate [8][9].

Eating kibble forces a dog’s body to work harder. To soften the dry food before digestion, their system pulls fluids from essential organs, which can create additional stress [8][9]. While dogs often try to make up for this by drinking more water, this reactive approach doesn’t offer the same consistent hydration that moisture-rich diets naturally provide [10].

Additives, Sodium, and Phosphorus in Kibble

Kibble’s low moisture content isn’t the only issue - it often contains additives and minerals that further strain kidney function. For example, kibble frequently has a salt concentration of around 1% (NaCl), which can interfere with water absorption and increase the workload on the kidneys [11].

Experts have raised concerns about the high levels of salt and phosphorus in kibble. Inorganic phosphorus, which is absorbed at rates as high as 90–100%, can overburden the kidneys and even contribute to cardiovascular problems [11][12].

"The average Labrador requires 1g of salt per day for normal function, but if fed 500g of dry food containing 1% salt, they consume 5 times their RDA of salt in every meal. Excess salt reduces the kidneys' ability to suck in water. This results in higher blood pressure, due to the extra fluid and strain on the delicate blood vessels leading to the kidneys (as well as causing all the cardiovascular diseases)" [11].

Phosphorus levels can also lead to hyperphosphatemia, a condition where soft tissues in the kidneys and blood vessels calcify [12]. Additionally, kibble often contains synthetic additives like preservatives, colorants, and anti-caking agents, all of which must be filtered by the kidneys. Another concern is ochratoxin (OTA), a toxin produced by mold found on grains, which has been detected in 47% of canned and dry pet foods tested [11].

The combination of these additives and low moisture content contributes to conditions that force the kidneys to work overtime.

How Kibble Increases Kidney Workload

The dual issues of low moisture and chemical additives place significant strain on a dog’s kidneys. To maintain hydration, the kidneys need to concentrate urine, which increases their workload over time [3].

"Be mindful: feeding processed kibble may not support your dog's kidney health optimally... Is low in water content - which may not adequately support hydration... Contains preservatives, artificial colors & synthetic additives – which may increase the toxin load... May add stress to your dog's kidney & immune system" [13].

High sodium levels in some kibble can worsen dehydration [2], while preservatives and synthetic ingredients add to the toxin load that the kidneys must filter. Dr. Jennifer Coates highlights the importance of hydration for kidney health:

"Kidney diets should also contain a lot of water. Dogs with kidney disease struggle to maintain their hydration... Wet foods are almost always a better option for dogs with kidney disease than dry foods" [2].

Over time, this cumulative strain underscores the risks of relying solely on dry kibble to meet a dog’s hydration needs.

Raw Diet vs. Kibble: Side-by-Side Comparison for Kidney Health

Main Comparison Factors

When it comes to kidney health, raw diets and kibble differ significantly in ways that can directly impact your dog's hydration and kidney function. Here's a closer look:

Factor	Raw Diet	Kibble
Moisture Content	70–75% [14]	6–10% [5]
Protein Quality	High-quality, digestible protein	Often rendered, lower-quality protein [16]
Carbohydrate Levels	Under 10% [14]	40–60% [14]
Phosphorus Control	Often formulated with controlled levels [17]	Typically higher in inorganic phosphorus
Additives	Minimal additives	Frequently contains additives
Kidney Workload	Reduced strain due to high moisture	Increased strain due to dehydration

This table highlights how raw diets, with their high moisture content and superior protein quality, offer clear advantages for kidney health compared to kibble. These differences are particularly crucial when considering how each diet supports hydration and reduces the kidneys' workload.

Raw diets, with 70–75% moisture, closely mimic the natural hydration levels found in ancestral diets. This high moisture content helps ease the kidneys' filtering responsibilities. In contrast, kibble's low moisture level (6–10%) can contribute to dehydration, forcing the kidneys to work harder.

Protein quality is another key factor. Raw diets typically include high-quality, digestible proteins that create less metabolic waste, reducing the strain on the kidneys. On the other hand, the rendering process used in many kibble products can degrade protein quality, making it harder for dogs to process and increasing kidney stress [16].

The carbohydrate content also varies dramatically between the two. Raw diets generally have less than 10% carbohydrates, while kibble contains around 40–60% [14]. High carbohydrate levels can lead to metabolic stress, further burdening kidney function.

Research and Clinical Findings

Scientific studies reinforce the benefits of high-moisture diets for kidney health. Since a dog's body is about 60% water, even a slight drop in hydration - around 10% - can lead to significant health concerns [15]. This makes the moisture content in raw diets especially valuable.

Kibble production processes can also introduce chemical changes, such as the creation of advanced glycation end products (AGEs). These compounds may contribute to kidney stress over time, especially in dogs already dealing with kidney issues.

For dogs with compromised kidney function, a high-moisture diet is even more critical. Such diets not only improve hydration but also support urinary tract health by easing the kidneys' workload and promoting better waste elimination.

Loyal Saints freeze-dried raw food offers a practical solution, combining the hydration benefits of raw diets with the convenience of a shelf-stable product. When rehydrated, it retains its moisture-rich content, supporting kidney function while using human-grade, all-natural ingredients to further minimize kidney strain.

The evidence consistently points to high-moisture, nutrient-dense raw diets as a better option for reducing kidney stress and maintaining optimal hydration for your dog.

Should You Feed Raw Food vs Kibble? Benefits and Risks - Dog + Cat Health Vet Advice

Hydration Tips for Dogs with Kidney Problems

Supporting your dog's kidney health involves carefully monitoring their hydration levels, as their kidneys work harder to filter waste and maintain body functions. Building on the hydration benefits of raw diets compared to kibble, here are some practical tips to help keep your dog hydrated and support their kidney health.

Adding Moisture-Rich Foods

Including foods rich in moisture is an effective way to enhance hydration. Wet foods, for instance, contain about 70–90% moisture [19], making them far more hydrating than dry kibble.

"Kidney diets should also contain a lot of water. Dogs with kidney disease struggle to maintain their hydration... a diet that has high water content is a great way to boost a pet's water intake when they have kidney disease." - Jennifer Coates, DVM [2]

Freeze-dried raw food, like the options from Loyal Saints, can be a great choice for dogs with kidney concerns. When rehydrated, it offers the moisture benefits of a raw diet while remaining shelf-stable and convenient. Plus, its human-grade, all-natural ingredients avoid unnecessary additives and fillers that could strain your dog's kidneys.

Another simple way to boost hydration is by adding a low-sodium broth to your dog's meals or serving it separately [18]. This not only increases fluid intake but also makes meals more enticing for dogs that may have a diminished appetite.

In addition to hydrating foods, always ensure your dog has access to fresh water.

Providing Clean, Fresh Water

Keeping your dog hydrated starts with providing clean, fresh water at all times. Change the water daily to avoid bacterial growth and ensure it remains appealing [1].

To encourage frequent drinking, place multiple water bowls throughout your home so water is always within easy reach [1]. A dog drinking fountain, which keeps water circulating and fresh, can also entice your dog to drink more [19].

When you're out and about, especially in warm weather, remember to bring water for your dog to prevent dehydration [19].

"Proper hydration plays a crucial role in preventing urinary and kidney problems in pets." - Guardian Veterinary Specialists [1]

These strategies are most effective when combined with tailored advice from your veterinarian.

Working with Your Veterinarian

Collaborating with your veterinarian is key to creating a hydration and renal diet plan suited to your dog's specific needs. Your vet can recommend low-sodium food options to minimize kidney strain and help develop a diet that supports overall health.

Research shows that proper hydration and a kidney-friendly diet can significantly improve life expectancy for dogs with kidney disease. For example, one study found that dogs on a kidney-specific diet lived an average of 13 months longer than those fed regular dog food [2].

"It's essential that you feed your dog with kidney problems a strictly renal diet only so that they can live a happy, relatively stress-free life with alleviated symptoms from their poorly kidneys. It's actually the most important part of your dog's treatment and could significantly improve their life expectancy." - Corinne Homer [21]

Since kidney disease affects about 10% of dogs, particularly older ones [20], regular veterinary check-ups are crucial. These visits allow your vet to monitor how dietary and hydration changes impact kidney function and make adjustments as needed, ensuring your dog gets the best care possible.

Conclusion: Picking the Right Diet for Hydration and Kidney Health

When it comes to managing your dog's kidney health, the role of diet can't be overstated. Hydration, as we've seen, plays a key role, and choosing the right food can make a significant difference - especially for dogs with kidney concerns.

Studies have shown that dogs on kidney-supportive diets can live up to 13 months longer than those eating standard dog food [2]. That’s a compelling reason to focus on nutrition and hydration when addressing kidney disease.

For dogs with kidney issues, high-moisture options like Loyal Saints freeze-dried raw food stand out. Once rehydrated, this option combines the benefits of a raw diet with the practicality of shelf-stable storage. Made with human-grade, all-natural ingredients, it avoids the preservatives and synthetic additives that can strain already compromised kidneys. Plus, it offers high-quality, easy-to-digest protein and naturally lower phosphorus levels [17]. In contrast, kibble often contains 40–60% carbohydrates and additives that may not align with what dogs need for kidney health [14].

A moisture-rich diet like this not only supports hydration but also eases the burden on weakened kidneys. Paired with veterinary guidance, it can help improve kidney function and potentially extend your dog's life.

FAQs

How can a raw diet help support kidney health in dogs compared to kibble?

A raw diet can play a key role in supporting kidney health in dogs by offering easily digestible, high-quality protein. This type of protein puts less strain on the kidneys while aiding their natural filtering processes. For dogs dealing with kidney issues, optimal protein sources are crucial to help their bodies function as efficiently as possible.

Another major advantage of raw diets is their high moisture content - typically 70-85%, compared to the much lower 10-15% found in kibble. This built-in hydration helps prevent dehydration and supports the flushing out of toxins, both of which are vital for healthy kidney function. For dogs with kidney concerns, staying hydrated is critical, and the moisture in raw meals makes it easier to meet their water needs directly through their food.

How can I help my dog stay hydrated if they eat kibble and have kidney concerns?

To keep your dog hydrated while on a kibble diet, consider adding warm water or low-sodium broth to their meals. Let the kibble soak for about 10–15 minutes - this not only softens the food but also increases its moisture. Another simple trick is to mix in a bit of wet food, which can both enhance hydration and make the meal more enticing.

Additionally, make sure your dog has access to fresh water at all times. A pet water fountain can be a great investment, as the movement of the water often encourages dogs to drink more. If your dog has kidney issues, it's important to check with your veterinarian to ensure their hydration needs are properly managed.

Can a raw diet support kidney health in dogs, and should I talk to my vet before switching their food?

A raw diet might benefit kidney health in dogs, especially when it includes easily digestible, high-quality proteins and is specifically designed to be low in phosphorus. These elements can help ease the workload on the kidneys and assist in managing chronic kidney disease.

That said, kidney disease can vary widely in severity, so it’s crucial to consult your veterinarian before making any dietary adjustments. Your vet can evaluate your dog’s condition and recommend a diet tailored to their specific nutritional needs, ensuring they get the proper nutrients while reducing the chance of complications or further kidney issues.