This is everything you need to know about kidney disease in dogs.
- What is canine chronic kidney disease?
- What do the kidneys actually do?
- What causes kidney disease?
- The protein myth
- What stage of kidney disease is my dog?
- How to treat your dog’s kidneys with diet?
What is canine kidney disease?
Chronic Kidney disease (CKD) is a progressive disease that is caused by structural or functional abnormalities in one or both of the kidneys. The reduction in the functional capabilities of the organs means a reduction in Globular filtration. Globular filtration is the kidney's ability to filter the blood. The reduction in the ability to filter the blood leads to a build-up of waste which becomes toxic, causing damage and further decline. (1)
The rate of progression of kidney disease in dogs is extremely variable, for example an early diagnosis of CKD can slow disease progression, and with the correct management, it will ensure your dog’s quality and length of life remains unaffected.
Depending on the stage of the disease, will depend on what management/ therapy your dog should receive, this is especially the case with diet. (2)
What do your dog’s kidneys do?
To understand how to care for a dog with kidney disease, you need to understand what the kidneys do for a dog.
Just like us humans, blood flows through the kidneys every single minute. Your dog’s kidneys filter out waste products that are in the blood (globular filtration) from the breakdown of food, old cells, toxins, metabolic by-products, and drugs. They also balance minerals like phosphorus, potassium, sodium and calcium.
All of these get into the blood via the digestive process, then the kidneys filter the blood and remove all waste in the form of urine. They also trap good substances, like proteins and supply them back to the body.
By controlling what your dog is digesting, you can control the waste.
Kidney Functions
- Remove waste material from the bloodstream
- Help regulate blood pressure
- Regulate levels of certain essential minerals such as calcium, phosphorus, potassium and sodium
- Produce a variety of hormones
- Regulate the amount of water in the blood and produce urine
- Stimulate red blood cells formation
- Help regulate vitamin D levels
By not overloading the functions of the kidneys, you will extend longevity.
What causes canine kidney disease?
A significant proportion of the treatment of a dog with kidney disease is addressing the underlying causes.
All of these causes either increase the workload of the kidneys, eventually causing it to deteriorate, or directly cause reduced function of the kidneys.
- Low-grade long term inflammation
- Increased waste in the food
- Gut Microbiome dysbiosis (wrong diet)
- Chronic bacterial infection
- High blood pressure
- Urinary blockage
- Certain drugs
- Congenital or at birth malformation of the kidneys
- Vitamin D deficiency
- Prolonged periodontal disease
(3,4,5,6)
The protein myth
There is no data at all, to suggest that high-protein diets affect the rate of kidney filtration. That means you should not restrict protein, however excess phosphorus is associated with disease progression and phosphorus is higher in lean high protein meats.
Increased dietary protein can be safely fed to dogs with CKD. (7) This is preferable as protein is a vital part of any healthy diet for a dog. (8)
If your dog is presenting high phosphorus levels in their blood, you can reduce the phosphorus by choosing higher fat meats and boiling the meat. (9)
What stage of kidney disease is my dog?
The Stages of Canine Kidney Disease - International Renal Interest Society Stage for Dogs (10)
The severity of your dog’s kidney disease and the loss of ability to filter the blood (globular filtration) is classed in Stages which you can work out from a blood test. Stages 1 and 2 are treated the same. Stage 3 is treated differently and Stage 4 even more so.
Stage 1 - Normal blood creatinine (less than 125 umol/l or slightly less than 1.4mg/dl) or normal or mild increase blood SDMA (18 or lower), proteinuria (protein in urine), abnormal renal biopsy results, increasing blood creatinine or SDMA concentrations.
Persistently elevated blood SDMA concentration (>14 µg/dl) may be used to diagnose early CKD.
Stage 1 is extremely manageable.
Stage 2 – Normal or mildly increased creatinine (125 - 250umol/l or 1.4 - 2.8 mg/dl), Mildly increased SDMA (18 – 35 ug/dl). Clinical signs are usually mild or absent.
Stage 2 is very much manageable.
Stage 3 – Creatinine levels higher (250 - 440umol/l or 2.8 - 5 mg/dl). SDMA levels (36-54)
Stage 3 the long-term outlook is dependent on the total loss of kidney function. Reduce protein levels of diet.
Stage 4 – The last stage. (440+ umol/l or 5+ mg/dl). SDMA levels (54+)
How to treat your dog’s Kidney disease with diet?
If you’d like balanced recipes for all stages, please get the Kidney Support Plan. If you’re looking for more support, or your dog has multiple issues, please sign up for a consultation.
Treatment of Kidney disease should be aimed at eliminating the underlying causes, to make sure to minimize further damage. Apart from congenital birth defects and medication, the underlying causes can all be treated with diet.
Protein
Protein restriction is only necessary when rebalancing abnormal blood work results, or for late-stage kidney disease. Long-term protein restriction is never advised.
Stage 1-2, it’s likely no protein restriction is necessary although some stage 2 dogs will show bloodwork that will need rebalancing. Stage 3 you may need to reduce it slightly, and stage 4 even more so.
The key to kidney longevity is reducing phosphorus, unfortunately, this is present in most meats, but less so in particular lean cuts.
Fat
Increased dietary fat content increases caloric density and palatability. Fat is tolerated by dogs with kidney disease and more fatty cuts of meats are advised to reduce phosphorus intake.
Carbohydrate and Fibre
In early-stage kidney disease (1 & 2) you’re going to be using small amounts of carbs (10%) of the meal), maybe medium amounts (20%) if your rebalancing bloodwork. For later stages, stage 3, you may be making carbs like cooked sweet potato and/ or rice 30% of the meal. Later stage diet will need to be around 40-50% carb. The inclusion of some fibre types increase the speed that food is transported through the gut, this reduces creatinine levels.
Vitamins and Minerals
Reducing phosphorus increase kidney longevity. That means for all kidney issues, you should reduce phosphorus, not eliminate it. Buying egg white pre-mix is an brilliant way to get protein into the diet that’s low in phosphorus.
Other specific ingredients can help to reduce phosphate from getting to the kidneys. E.g. You can reduce phosphorus by using low-phosphorus‹› ingredients and including phosphate binders like ground eggshell and raw natural honey.
Regular blood test (1 per 3 months) will give you a great indication of how your dog’s kidneys are working and which minerals need balancing.
- Practice, 41(1), pp.15-30.
- Evason, M. and Remillard, R., 2017. Chronic kidney disease staging & nutrition considerations. Clinician’s Brief, 15(3), pp.89-95.
- Dunaevich, A., Chen, H., Musseri, D., Kuzi, S., Mazaki‐Tovi, M., Aroch, I. and Segev, G., 2020. Acute on chronic kidney disease in dogs: Etiology, clinical and clinicopathologic findings, prognostic markers, and survival. Journal of Veterinary Internal Medicine, 34(6), pp.2507-2515.
- Brown, S.A., Crowell, W.A., Barsanti, J.A., White, J.V. and Finco, D.R., 1991. Beneficial effects of dietary mineral restriction in dogs with marked reduction of functional renal mass. Journal of the American Society of Nephrology, 1(10), pp.1169-1179.
- Finco, D.R., Brown, S.A., Crowell, W.A., Duncan, R.J., Barsanti, J.A. and Bennett, S.E., 1992. Effects of dietary phosphorus and protein in dogs with chronic renal failure. American journal of veterinary research, 53(12), pp.2264-2271.
- Simona Mihai, Elena Codrici, Ionela Daniela Popescu, Ana-Maria Enciu, Lucian Albulescu, Laura Georgiana Necula, Cristina Mambet, Gabriela Anton, Cristiana Tanase, "Inflammation-Related Mechanisms in Chronic Kidney Disease Prediction, Progression, and Outcome", Journal of Immunology Research, vol. 2018, Article ID 2180373, 16 pages, 2018. https://doi.org/10.1155/2018/2180373
- Sanderson, S.L., Rethinking Protein Restriction in Aging Dogs and Cats with Chronic Kidney Disease. Premise of Systems Microbiomics in Improving Health and Related Diagnostics for Human and Companion Animals, p.87.
- Leibetseder JL, Neufeld KW. Effects of Medium Protein Diets in Dogs with Chronic Renal Failure. J Nutr. 1991;121: S145-S149
- Jones, W.L., 2001. Demineralization of a wide variety of foods for the renal patient. journal of Renal Nutrition, 11(2), pp.90-96.
- Finco DR, Brown SA, Crowell WA, et al. Effects of Dietary Phosphorus and Protein in Dogs with Chronic Renal Failure. Am J Vet Res. 1992;53:2264-2271.