Feeding Cats in the Early Stages of Chronic Renal Failure

Protein and phosphorus must not be reduced too much.

Fine adjustment required

In azotemic chronic kidney disease (CKD), restriction of dietary phosphorus and protein is the cornerstone of therapy, but for cats with early-stage CKD, the long-term effects of such a diet on kidney function have been little studied. Results are now available from a laboratory study involving 19 cats who had CKD Stage 1 or 2 at baseline.

Long-term study with the change of feed

In the first phase of the study, all cats received a dry food that was greatly reduced in protein and phosphorus (Royal Canin Veterinary Diet Feline Renal Dry, Protein: 59 g/Mcal, phosphorus: 0.84 g/Mcal, calcium-phosphorus ratio: 1, 9). In the second phase of the study, the animals received a moderate protein- and phosphorus-reduced feed for 22 months (wet and dry food, each 50 percent of the energy requirement, (Royal Canin Senior Consult Stage 2 [now renamed to Royal Canin Early Renal]), protein: 76 to 98 g/Mcal, phosphorus: 1.4 to 1.6 g/Mcal, calcium-phosphorus ratio: 1.4 to 1.6) Measurements included total calcium, phosphorus, and the hormone FGF23, which is involved in phosphate regulation is.

Results and conclusion

At baseline, mean calcium, phosphorus, and FGF23 levels were within the normal range for healthy cats. The phosphorus value remained relatively constant throughout the study. In the first phase of the study, under strict protein and phosphorus restriction, mean calcium levels increased and towards the end exceeded the upper limit of the normal range for total calcium in 5 cats and ionized calcium in 13 cats. The mean FGF23 level increased to 2.72 times the baseline value. In the second phase of the study, with moderate protein and phosphorus reduction, total calcium normalized in all previously hypercalcemic cats, and ionized calcium normalized in several of these cats. The mean FGF23 level was halved.


Cats in the early stages of CKD developed hypercalcemia when severely reduced in protein and phosphorus, which resolved after switching to a diet with moderately reduced protein and phosphorus content. In addition, the kidney markers and the calcium-phosphorus ratio improved with a moderate diet. The authors conclude that a diet moderately reduced in protein and phosphorus may be beneficial for cats with early-stage CKD.

Frequently Asked Question

What can cats with kidney failure eat?

The meat should be predominantly muscle meat with high-fat content. Goose or duck meat, fatty beef (prime rib, head meat, side rib), or boiled or roasted pork are well suited here. Oily fish like salmon or mackerel will do once a week.

How can you improve kidney values ​​in cats?

One of the most common treatment measures is a special kidney diet. Your cat with kidney disease must comply with this for the rest of its life. In addition, the veterinarian will prescribe medication (such as ACE inhibitors or antihypertensive drugs) and recommend supportive therapies.

Can kidneys recover in cats?

Acute means your cat has had kidney disease for a short time. With timely treatment, the kidneys can often fully recover from acute renal failure. Chronic kidney disease means your cat’s kidneys have been diseased for a long time.

What is good for the kidneys in cats?

A diet rich in potassium and magnesium is therefore generally recommended for cats with kidney disease. Have your cat’s blood potassium levels checked regularly?

How often is infusion in cats with kidney disease?

As much as the cat tolerates and still eats the food. You can also bring the cat to the veterinary practice at regular intervals for a stationary intravenous infusion. Or you can give a liquid under the cat’s skin about twice a week at home.

Why do so many cats have kidney disease?

Kidney problems in cats can be caused by infections, high blood pressure, or genetics. The intake of toxic substances – including certain indoor plants or heavy metals (lead, mercury) – can also cause severe kidney damage.

What vitamins are in renal failure cats?

The supply of water- and fat-soluble antioxidants such as vitamin C, vitamin E, and ?-carotene is recommended since oxidative stress in kidney tissue can contribute to the progression of the disease.

When should a cat with renal failure be euthanized?

Anyone who owns a cat with kidney disease will at some point be faced with the question: When do I have to put my cat with kidney disease down? If the cat with kidney disease has reached end-stage CKD and the kidneys are failing and the cat is just suffering, your vet will let you know.

Mary Allen

Written by Mary Allen

Hello, I'm Mary! I've cared for many pet species including dogs, cats, guinea pigs, fish, and bearded dragons. I also have ten pets of my own currently. I've written many topics in this space including how-tos, informational articles, care guides, breed guides, and more.

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