DIETARY THERAPY OF RENAL FAILURE
As can be seen from the table of contents of our Kidney Failure Center, there are many aspects of kidney failure that require attention. Diet can be used to help in many ways and we are lucky to have commercially available diets made specifically for renal patients. There are even diets made for different stages of Kidney Failure. The goal of therapy, dietary or otherwise, is to prevent or at least postpone advanced uremia (poisoning by toxins the kidneys could not adequately remove) and extend life expectancy.
In one famous study where 38 dogs in kidney failure were tracked for 2 years,
Another study in dogs showed that beginning the renal diet
A study of 50 cats with stable naturally occurring renal failure were
Clearly there is tremendous benefit to the patient in switching to a prescription renal diet. Unfortunately, these diets tend to be more bland than what the pet may be used to and they are not always acceptable to the pet.
Let’s review some basic features of a desired diet. There are many misconceptions about an appropriate diet for renal disease. In fact, what dietary modifications should be made depend on the stage of renal disease. Some basic desired qualities in a renal diet are:
Since a number of renal toxins come from the metabolism of protein, one way to give the kidneys less work to do is to eat less protein. How much less protein depends on how serious the kidney disease is. Older animals tend to require a higher dietary protein level in general when compared to their younger counterparts. Protein also adds palatability to the food so that if we try to restrict protein too much we may end up with a pet who will not eat at all. Further, there is a metabolic requirement for protein below which a diet cannot dip. This has led to diets with differing protein restrictions to fit with different stages of disease, less restriction for earlier stages.
This is a very important part of a renal diet since phosphorus balance is crucial. Phosphorus comes into the body via the diet and leave the body via the kidney, only in renal failure phosphorus is not well removed as it is supposed to. Obviously using less phosphorus in the diet may be adequate to keep the blood phosphorus levels normal, balancing the intake with the output but sometimes addition of medication (i.e. a phosphate binder) is needed to further reduce intake. Restricting dietary phosphate has been shown to slow the progression of renal disease. For details on goals for the phosphorus level and more details on managing phosphorus click here.
If the goal phosphorus level has not been achieved in 2-4 weeks
OMEGA 3 FATTY ACIDS
Studies suggest that kidney failure patients taking omega 3 fatty acids are likely to live longer than patients who do not take them. This has led to the supplementation of most renal diets with fish oils. The full import of fatty acid supplementation is still being worked out.
Other dietary features include B vitamin supplementation (since the damaged kidneys tend to lose excess B complex), non-acidifying features to help control acidosis.
AT WHAT POINT SHOULD A SPECIAL DIET BE STARTED?
This has been a controversial question for a long time. For many animals changing diet so a less palatable food represents a definite reduction in life quality. There was some thinking that we are changing the diet too soon. On the other hand, if a pet is in a more advanced state of disease before the switch is made, the pet will be much less willing to change to a food of less palatability. The diet companies that make these foods have put a great deal of research into improving palatability over the years which has helped tremendously and, finally, the International Renal Interest Society finally has guidelines.
They recommend changing the diet to a renal food when a dog’s creatinine level is in the 2.1-5 mg/dl range (Stage III renal failure). For cats the diet should change when the creatinine reaches approximately 2.0 mg/dl (middle Stage II renal failure).
These guidelines allow the patient to benefit the most from the preventive advantages of the diet. If the pet finds the diet palatable then there should be no life quality issues with changing foods.
HOME COOKING A RENAL DIET
Home cooking an appropriate renal diet is a complicated task but it can be done. Because different pets experience different problems with their renal disease (potassium depletion or not, pH issues or not, different degrees of phosphorus restriction needed etc.), the diet should ideally be tailored to the individual.
Your veterinarian can get you an appropriate recipe through:
(Because these are prescription diet formulas you cannot access them on your own.)
Several recipes have been published by Dr. Donald Strombeck, one of the internal medicine specialists at the University of California at Davis. These recipes can be viewed at:
We cannot vouch for other recipes found on this site but can say that often published recipes prove nutritionally incomplete when scrutinized. The Strombeck recipes are complete and balanced.
For more detailed recipe and expert adjustments, a veterinary nutritionist can be consulted. There are several university nutrition departments that offer this service but we have found the best service from a private company:
Expect a consultation with a veterinary nutritionist to cost anywhere from $150 to $200.