Introduction
Kidney disease is a common condition in cats, especially as they age. As the kidneys fail, they are unable to effectively filter waste products from the blood. This results in the buildup of harmful toxins in the body. Diet plays an important role in managing kidney disease. There are key differences between dry and wet cat food that impact kidney health.
This article provides an overview of kidney disease in cats and examines if wet cat food is better for cats with kidney problems. It compares dry vs. wet food and looks at important factors including water content, protein, phosphorus, sodium, palatability, and prescription renal diets.
Dry vs Wet Cat Food
There are a few key differences between dry and wet cat food that are important to consider when choosing the best option for a cat with kidney disease.
Dry cat food typically contains around 10% moisture whereas wet cat food contains around 75-85% moisture. The higher moisture content in wet foods can help increase a cat’s water intake, which is beneficial for cats with kidney disease since they need extra fluids (1).
However, one downside of wet foods is they usually contain higher amounts of phosphorus and sodium compared to dry food. Excess phosphorus and sodium can put additional strain on the kidneys, so this is something to watch out for (2).
When it comes to protein content, wet foods tend to have higher protein levels. Higher protein diets may help cats maintain muscle mass and body condition as kidney disease progresses. However, very high protein diets could potentially worsen kidney function so moderation is key (1).
In terms of palatability, wet foods are often more appetizing to cats compared to dry kibble. This can be advantageous in stimulating appetite and increasing food intake for cats who are picky eaters or experiencing appetite loss (1).
Overall, while wet foods have benefits like higher moisture and protein, pay attention to phosphorus and sodium levels. Consulting a vet is advised to determine the best balance of wet and dry foods for an individual cat with kidney issues.
Sources:
(1) https://www.petmd.com/cat/nutrition/wet-cat-food-vs-dry-cat-food-which-better
(2) https://www.dailypaws.com/cats-kittens/cat-nutrition/cat-food/wet-vs-dry-cat-food
Water Content
Wet cat food contains much more water than dry food, which can help cats with kidney disease stay hydrated. Dry cat food typically has only around 10% water content, while canned wet food contains approximately 75-78% water. Cats fed only dry food would need to drink a substantial amount of water separately to compensate. However, cats with kidney disease often have a reduced thirst response, so they may not drink enough on their own. The high moisture content in wet food helps these cats get water through their diet.
According to sources, cats fed exclusively wet food may drink very little additional water, since their moisture needs are met through their food. The high water content in wet food can help improve hydration for cats with kidney disease. This is extremely beneficial, since dehydration can exacerbate kidney problems. By choosing wet cat food, owners can help their cats with kidney disease stay optimally hydrated.
Sources:
https://bluebuffalo.com/articles/cat/wet-your-cats-appetite/
https://www.quora.com/Is-it-normal-for-cats-who-are-fed-an-all-wet-food-diet-to-drink-very-little-water
Protein Content
Managing protein intake is important for cats with kidney disease. According to the VCA Hospitals, the recommended range of protein on a dry matter basis for cats with CKD is 28-35%. If protein intake is too low however, CKD will start to break down muscle tissue to get the amino acids it needs. But too much dietary protein may put additional strain on the kidneys.
As outlined in a study from Royal Canin, the current NRC recommended intake of dietary protein for adult cats is 50 grams/1000 kcal ME (metabolizable energy). This represents a 25% increase over the previous recommendation. For cats with CKD, a level of protein intake between this value and 35 g/1000 kcal ME is suggested.
Ultimately, the ideal protein intake depends on the individual cat and should be determined in consultation with a veterinarian. They can recommend an optimal kidney diet to help manage protein levels.
Phosphorus Content
Phosphorus is an essential mineral for cats, but too much can be damaging for cats with kidney disease. As the kidneys fail, they lose the ability to eliminate excess phosphorus from the body. This causes phosphorus to build up in the blood, potentially leading to serious complications like heart disease and bone problems.
In general, wet cat foods have lower levels of phosphorus compared to dry kibble. This is because during the manufacturing process of dry food, phosphorus is added as a preservative and for texture. Canned food tends to have lower and more natural levels from the raw ingredients (Your Guide to Wet vs Dry Cat Food, 2021).
For cats with kidney disease, it’s recommended to feed a diet low in phosphorus, ideally containing less than 0.6% on a dry matter basis for advanced kidney disease. This usually requires a special veterinary therapeutic diet. However, some high quality grain-free wet foods may have lower phosphorus levels around 0.7-0.9% and can be fed occasionally for variety.
Overall, choosing a wet food diet is advisable to help limit phosphorus intake for cats with kidney disease. But be sure to read labels and consult your vet on the best options.
Sodium Content
Wet cat foods tend to be significantly lower in sodium compared to dry foods. According to one study, the average sodium content in wet cat foods was 0.6 g/100g as fed while dry foods averaged 2.3 g/100g as fed (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6868456/). Another source notes that dry foods normally contain a high amount of salt and sugar (https://catoropets.com/blogs/news/wet-vs-dry-cat-food-which-is-better).
This is an important consideration for cats with kidney disease. Sodium can cause increased thirst and urine production, which taxes the kidneys. Limiting sodium intake is often recommended to support kidney health. The low moisture content of dry foods also contributes to dehydration. Therefore, feeding a wet food diet with lower sodium content may help cats with kidney disease stay hydrated while reducing strain on their kidneys.
Palatability
Wet food is often more palatable and tempting for cats with kidney disease. As the disease progresses, cats tend to eat less due to nausea and changes in taste perception. According to VCA Hospitals, “Commercially available kidney support diets tend to be quite palatable because increased palatability encourages appetite.” https://vcahospitals.com/know-your-pet/nutrition-for-cats-with-chronic-kidney-disease Wet food has higher moisture content and generally has a stronger aroma and flavor than dry food, making it more enticing for picky eaters. Choosing a wet food formulated for kidney support can help tempt cats to eat, increasing nutrient intake. However, some cats may still prefer dry food, so following your vet’s specific recommendations for your cat is important.
Prescription Renal Diets
Prescription kidney diets are formulated to help slow the progression of kidney disease in cats. Both wet and dry prescription foods for cats with kidney disease are available. Some of the top prescription wet and dry cat foods for kidney disease include:
Hill’s Prescription Diet k/d Kidney Care – Available in both wet and dry forms. Formulated with controlled phosphorus and sodium levels. Higher fat and calorie content to prevent weight loss. Antioxidants to support kidney health. Source
Royal Canin Renal Support – Features a low phosphorus level to support the kidneys. Increased levels of omega-3 fatty acids for kidney health. Antioxidants to reduce cell damage. Comes in wet and dry varieties. Source
Purina Pro Plan Veterinary Diets NF Kidney Function – Restricted phosphorus and sodium levels. Increased calories and fat to maintain body weight. Omega-3s for kidney support. Available as wet food or dry kibble. Source
These prescription diets are formulated under veterinary guidance and designed specifically to benefit cats with kidney disease. Following a vet-recommended prescription diet can help manage this condition.
Other Tips
In addition to controlling protein, phosphorus, and sodium, there are other diet considerations for cats with kidney disease. Antioxidants may help protect the kidneys from further damage. Foods rich in antioxidants like vitamin E, vitamin C, and beta-carotene can help reduce inflammation and oxidative stress on the kidneys.[1] Therefore, choosing cat foods with added antioxidants can provide benefits.
Some other tips include:
- Encouraging water intake by feeding wet food, adding water to dry food, or using fountains.
- Avoiding excess phosphorus by limiting dairy, organ meats, fish.
- Choosing easy to digest options since kidney disease can cause nausea.
- Feeding smaller, frequent meals to maintain appetite.
Work closely with your veterinarian to develop the ideal kidney diet for your cat based on their lab values and health status.
Conclusion
In summary, wet food is generally better for cats with kidney disease due to its higher water content and lower levels of phosphorus and sodium. The increased water intake can help dilute toxins and flush the kidneys. Prescription renal diets, whether wet or dry, are formulated to support kidney health. When transitioning to a renal food, introduce it gradually mixed with your cat’s current diet. Make sure fresh water is always available. Feed smaller, more frequent meals. Foods with added L-carnitine and omega-3 fatty acids may also benefit kidney function. Monitor your cat closely and follow up regularly with your veterinarian. The bottom line is wet food supports hydration and reduces kidney workload, so it is recommended for cats with renal issues. However, work closely with your vet to determine the best diet for your individual cat.
