Urine test

Blood/serum tests

CRF Diet

The low-protein myth

What to feed




  • Do not use Uva Ursi, also known as Bearberry on a cat with CRF because it has a strong astringent effect, and in any case, is only indicated for short-term use in confirmed alkaline urine, like with a bout of cystitis.
  • Also do not give a CRF cat the herb Juniper Berries because it can irritate the kidneys.
  • Cats with CRF are prone to high blood pressure so stay away from Licorice and Horsetail as well.

Subcutaneous (subq) Fluids


  • Potassium: Although a small % of cats with CRF can have elevated potassium (K) levels, they are generally more likely to have lower than normal blood potassium levels. It is possible for a cat to have normal potassium readings on a blood test, and still have low potassium levels in the tissues. So rather than wait till K level is down to 4 mEq/L, it's best to try and keep K around 4.5 - 5mEq/L through dietary choices or failing that, through supplementation.
  • The best choices for this are - potassium gluconate or potassium citrate @ 2 to 6mEq i.e 78mg - 234mg of elemental potassium, that is, between 468 mg and 1,404mg potassium gluconate/citrate (as stated on the label) daily
  • If your cat has metabolic acidosis, then Citrate is a better choice than Gluconate, but in early to mid-stage CRF, gluconate is a good choice. Avoid K Chloride which is indicated for metabolic alkalosis, as it can make your cat's problems worse.
  • Vitamins and trace minerals: Be aggressive with supplementation of water-soluble vitamins - C, and B-Complex as well as trace minerals. Be more cautious with fat-soluble vitamins such as A, D, E, and K which are stored in the liver.
  • Fish Body (not liver) Oils e.g. salmon, sardine, anchovy, or krill oil: 1-2 1,000mg softgels (depending on omega-3 in diet, adjust up/downward) with at least 180mg EPA and 120mg DHA e.g. Carlson's and Nordic Naturals brands. NOW brand krill oil is reasonably-priced and easy to squirt into food plus many cats actually like the taste.
  • L- taurine powder or capsule: 500 - 1,000mg NOW/Source Naturals/LEF brands
  • Coenzyme Q10 a.k.a. CoQ10: 30 - 60 mg e.g. Doctor's Best, NSI; get capsules so you can avoid plant-based oils (cats hate 'em anyway)
  • Glandulars or PMG products: Over the last 11 years, these products have been shown to greatly benefit our list cats with compromised kidneys. They have been helpful not only in keeping BUN and Creatinine levels in check, but other non-kidney glandulars can help with anemia as well. Use the ones marketed for humans e.g. Standard Process' Renatrophin and Renafood because they contain more meat and a lot fewer oddball ingredients than the "feline" formulas. These would have to be customized for your cat in terms of which type, exact amounts, and for how long.
  • Phosphate binder: Using aluminum as an oral phosphate binder (OPB) is not something I feel comfortable with. Medscape is replete with information on negative aspects of aluminum hydroxide e.g. just one of many examples:
  • "Of the commonly used phosphate binders, aluminum hydroxide is associated with aluminum toxicity and calcium carbonate is associated with hypercalcemia." 'Nuff said.
  • As a safer alternate OPB, I have been using eggshell powder (ESP) which is a natural source of calcium carbonate (e.g. Epakitin, which also contains chitosan). In the paper by Brown et al, linked and referenced below, Epakitin was found to not increase calcium levels (risk for CRF cats), in fact both PTH and Calcium decreased, as did serum Phosphorous level.
  • I prefer ESP which has the added benefit of being cheap, and easy to prepare at home. I have used ESP as an OPB to good effect. I use Dr. Nagode's guidelines (FWIW, his are for aluminum binders, not ESP) where a 5kg/11lb would need 300-500mg (~ 1/7 - 1/4 tsp) of ESP per day if Phosphorous level is between 6 and 8mg/dl, increasing ESP with higher Phosphorous levels even up to twice those amounts as Phos gets in the 7-8 range In comparison Brown et al, gave 1g twice a day for cats weighing under 5kg.
  • Probiotics: There is limited research support for a formula - Azodyl - containing the following strains of beneficial bacteria - Streptococcus thermophilus, Lactobacillus acidophilus, and Bifiodobacterium longum. The former 2 are in yogurt, but to get high enough numbers, one can get a product such as Source Naturals Life Flora. One can even mix 1/8 or 1/16 tsp of this powder into yogurt or another treat your cat likes.
  • Psyllium husk and/or cooked squash/pumpkin: There are no cat studies on psyllium, and as far as we know at this point, it is less fermentable than pumpkin or rice bran both of which are moderately fermentable, hence ideal for cats as these fiber feed gut bacteria. Probiotics together with fermentable fiber (which functions as a pre-biotic) trap some of the nitrogen, and instead of it being processed by the kidneys (BUN), it is excreted via stool thus keeping it from building up in the system.

Notes and References

  1. Coenzyme Q10 Good for People with Kidney Failure
  2. In this study, CoQ10 lowered serum creatinine by 29% and blood urea nitrogen by 9%:
    Singh RB, Khanna HK, Niaz MA, "Randomized, Double-Blind Placebo-Controlled Trial of Coenzyme Q10 in Chronic Renal Failure: Discovery of a New Role, J Nutr Environ Med, 2000;10:281-288.36843
  3. Herb of the Season: Stinging Nettle (Urtica dioica) By David Winston, AHG
    These researchers found that "Diets replete in protein were not associated with increased severity of glomerular or nonglomerular renal lesions, increased proteinuria, or decreased GFR. Diets replete in calories were not associated with increased severity of glomerular lesions, but were associated with mild increase of nonglomerular lesions. Factors other than protein and calorie intake must be considered potential causes of progression of renal failure in cats. Results raise questions about the practice of restricting quantity of protein in the diet of cats with chronic renal failure, with the intention of ameliorating development of further renal damage."
  4. Finco DR, Brown SA, et al Protein and calorie effects on progression of induced chronic renal failure in cats, American Journal of Veterinary Research, 1998, 59(5): 575–582
  5. Finco DR, Brown SA, Barsanti JA. "Divergent views on dietary management of renal failure: The Georgia experience". Proc 16th Ann ACVIM Forum 1998; 32-33.
    I could not find a link to this paper online, but do have a hard copy of it. Dr. Finco et al found that feeding cats with CRF diets "replete in protein" did not accelerate renal failure as measured by serum creatinine/BUN, nor did it have any other negative effects such as uremia and/or azotemia.
    In this great literature review, the authors underscore that not only does reduced protein not help, it can hurt. To wit: "Disadvantages to reduced protein intake include reduced kidney function as measured by GFR and renal plasma flow, possibility of a negative nitrogen balance, and the promotion of acatabolic state in the presence of proteinuria."
  6. Bovee, Kenneth C. DVM, MMedSc,"Mythology of Protein Restriction for Dogs with Reduced Renal Function", Practicing Veterinarian Vol. 21, 11 (K), Nov 1999
    This study showed higher EPA levels and lower AA levels might have a renal-protective effect:
  7. Plantinga EA, Hovernier R, Beynen AC, Qualitative risk assessment of chronic renal failure development in healthy, female cats as based on the content of eicosapentaenoic acid in adipose tissue and that of arachidonic acid in plasma cholesteryl esters., Vet Res Commun. 2005 May;29(4):281-6.
    Study showing diets hi in EPA (omega-3) good predictor of survival time:
  8. Plantinga EA, Everts H, Kastelein AM, Beynen AC. Retrospective study of the survival of cats with acquired chronic renal insufficiency offered different commercial diets, Vet Rec. 2005 Aug 13;157(7):185-7
    A fantastic article that should be a must-read for vets and caregivers alike; cogent arguments for not restricting protein. Alas, this is no longer available, but I do have this quote from it when I posted it to my forum -- "There is no evidence to believe that low protein diets are beneficial to all patients with renal azotemia (increased BUN and creatinine with isosthenuric urine specific gravity) and in fact this practice may be harmful to some patients."
  9. Nutritional Management of Dogs and Cats with Chronic Renal Failure - Dr. Tina Kalkstein
    In this study, cats fed a high-protein (51.7% protein) diet had higher HCT values, weighed more, and had lower K levels (reversed with supplementation); begs the question why they fed only 0.3% K to cats with CRF when daily requirement is supposed to be 0.6% (ahem!):
  10. Adams LG, Polzin DJ, Osborne CA, O'Brien TD., Effects of dietary protein and calorie restriction in clinically normal cats and in cats with surgically induced chronic renal failure, Am J Vet Res. 1993 Oct;54(10):1653-62.
  11. Tomohide Koizumi, Kazuya Murakami, Haruyuki Nakayama, Tomomi Kuwahara, and Yoshinari Ohnish Role of dietary phosphorus in the progression of renal failure, Biochemical and Biophysical Research Communications, Volume 295, Issue 4, 26 July 2002, Pages 917-921
  12. Sunvold G.D., Vickers R.J., Reinhart G.A. Effect of Fermentable Fiber Blends on Nitrogen Repartitioning in the Feline, North American Veterinary Conference, Orlando, Florida, USA, January 19, 2000
  13. Brown, Scott A., VMD, PhD, Marjorie Rickertsen, BS, Suzanne Sheldon, DVM, Effects of an Intestinal Phosphorus Binder on Serum Phosphorus and Parathyroid Hormone Concentration in Cats With Reduced Renal Function, Intern J Appl Res Vet Med Vol. 6, No. 3, 2008.