Can Meat Cause Kidney Failure?
Veterinarian and raw-diet advocate Ian Billinghurst addresses concerns.
There are innumerable individuals and organizations that promote their beliefs – for various reasons – that feeding dogs anything other than commercially manufactured dog food is deleterious to canine health. If this were true, dogs wouldn’t even be here today, since the commercial dog food industry itself is less than a century old, and dogs have been successfully fed by humans considerably longer than that.
Nevertheless, our readers tell us all SORTS of explanations that they have heard from their veterinarians, trainers, breeders, or friends as to why they should not feed their dogs a “bones and raw food” (a.k.a. “biologically appropriate raw foods” or “BARF”) diet. Some of these objections are completely nonsensical and easily dismissed, such as the claim that “dogs cannot digest raw meat properly.”
Other concerns make sense, such as the possibility that a homemade diet may not provide a proper balance of nutrients. We feel that sensible concerns such as these are easily addressed; as we’ve said before, feeding dogs really isn’t rocket science.
Still other times, however, readers bring us questions about a BARF diets that would be best answered by a veterinarian – preferably one who has a lot of experience with these diets. There may be no better candidate fitting this description than Dr. Ian Billinghurst, an Australian veterinarian who is also the author of two wonderfully detailed instructional books, Give Your Dog A Bone and Grow Your Pup With Bones. Though our readers could answer many of their own questions by an in-depth reading of either or both of Dr. Billinghurst’s books (which we heartily recommend), Dr. Billinghurst has agreed to answer questions about BARF diets for WDJ and our readers.
The first of these question-and-answer articles appears below, and we invite further questions. Do you have a basic concern about BARF diets that you would like addressed before you try such a diet on your dog? Or are you an experienced “BARFer” who has a detailed question you haven’t been able to find an answer for anywhere else? Bring it on!
Address your question to: Whole Dog Journal BARF Question, 1175 Regent Street, Alameda, CA 94501; or fax to (510) 749-4905, or email email@example.com.
Last month, after changing the diet of my seven-year old male dog, Hobo, from a grocery store dry food diet to a raw meat diet for two weeks, Hobo died of kidney failure. His BUN value was very high. My suspicion is that his kidneys could not process the high protein food. Although dogs descend from wolves, is it possible that some of them have lost the “gene” for eating either high protein foods or contaminated foods?
We have now adopted another dog, Princessa, from the local pound and have our hands full getting her settled in.
Dr. Billinghurst responds:
Thank you very much for your letter. We are all very sad to hear of Hobo’s death. However, it is wonderful that his life can be used to help the owners of other animals who are afraid of the BARF diet because of the possibility that it might be a cause of kidney failure.
You see, the truth is, under the circumstances you describe, it cannot. Your letter has highlighted a number of misconceptions regarding kidney failure and high protein diets.
One of the first things I must point out is that an ALL-MEAT diet is not a BARF diet and is certainly not a biologically appropriate or a properly formulated evolutionary diet. Having made that point, let me now take you through the causes of kidney failure so we may set your mind at ease regarding those causes, and the safety of a properly formulated BARF diet with respect to kidney function, kidney health, and kidney failure.
What is “kidney failure”?
This is a condition where the kidneys fail to remove waste products of metabolism from the blood and they fail to regulate the balance in the body of fluids, electrolytes, and pH. The underlying cause can be a problem of the kidneys themselves, but it can also be due to other body systems malfunctioning or being diseased. In addition, when kidneys fail, the failure can be either acute or chronic.
Acute kidney failure is abrupt in onset and is often able to be reversed if recognized early and treated appropriately. By contrast, chronic kidney failure develops over a number of years and is the end result of long-term damage that cannot be repaired.
When kidneys stop working properly (either as an acute reversible episode or as a chronic irreversible state) they fail to remove nitrogenous wastes from the blood. These nitrogenous wastes include urea, creatinine, and other compounds. The compounds we normally look for in blood tests are urea and creatinine. When these are found in high concentrations in the blood, we know that the kidneys have not been working well enough to be able to remove them from the blood.
Acute kidney failure
The causes of acute kidney failure are divided into three groups. The first group of causes of acute kidney failure are those causes which decrease the flow of blood to and through the kidneys. This is the most common form of acute kidney failure and may be reversible if the cause of the reduced blood flow can be identified and corrected within 24 hours. Common causes of reduced blood flow would include shock, hemorrhage, and heart failure. At this time, urine output is greatly reduced or nil. The causes of shock are numerous and can range from acute trauma to some form of acute disease condition such as pancreatitis.
The second group of causes of acute kidney failure are related to damage to the kidneys themselves, although the primary problem may also be external to the kidneys as it was with the first group. For example, if there has been muscle trauma, the resulting myoglobin in the blood may block the tiny tubes within the kidneys causing kidney failure. Or, if there has been heart failure, there may be poor blood flow to the kidneys, which causes the cells of the kidneys to die. Alternatively, toxins (including drugs) may result in kidney cell death, and of course kidney infection may also result in acute kidney failure.
The third group of causes of acute kidney failure include some form of obstruction to urine flow after the urine leaves the kidneys. A common cause would be a blockage caused by crystals formed in the urinary tract or in the case of males it may relate to an enlarged prostate.
As you will appreciate, the symptoms seen with acute kidney failure reflect the underlying cause, whether it be signs of infection, heart failure, pancreatitis, urinary stones, enlarged prostate or whatever. On top of those signs relating to the underlying cause of the acute kidney failure will be a second set of signs which relate to the kidney failure itself. These acute kidney failure signs are generally recognized as being divisible into two phases.
The first phase of acute kidney failure is a period during which there is marked reduction in urinary output. The second stage of acute kidney failure is characterized by a marked increase in urinary output.
It is the first stage of acute kidney failure which is most critical. Fluid retention will cause edema which may result in fluid in the lungs, there will be a critical rise in blood pressure ,and the retention of wastes will result in severe acidosis/toxicosis. If untreated, this deadly combination may result in convulsions, coma, muscle weakness, heart failure, gastrointestinal bleeding, infection, and ultimately death. Infection is a major cause of death in dogs with acute kidney failure, although death may also be caused by any of the other underlying causes.
Assuming treatment – of the underlying cause and the damage to the kidneys – has been successful, the second stage of acute kidney failure will begin within days to weeks after the first stage. It marks the time when the kidneys have recovered sufficiently to allow the production of urine. During this period the BUN and the creatinine may well remain elevated for some time, but will return to normal as and if the kidneys recover.
Please note at this point that excessive protein in the diet is nowhere to be seen as a cause of acute kidney failure.
Chronic kidney failure
Chronic kidney failure represents progressive destruction of kidney structures over many years. The progression of this form of kidney failure usually occurs in three stages, as follows:
• The First Stage Of Chronic Kidney Failure
This is called the renal impairment stage. When this stage is reached, it means that the kidneys have been damaged to the point that they have lost up to 50 percent of their function. Sometimes no signs of problems are seen at this stage, but the signs can also include slightly excessive drinking and urinating. At this stage, by limiting protein, calcium, and phosphorus in the diet of these patients, the progression of renal disease may be slowed dramatically, but unfortunately it cannot be completely halted.
• The Second Stage Of Chronic Kidney Failure
This is called the stage of kidney insufficiency. This is the stage where the ongoing kidney damage is such that the kidneys have lost between 60 and 80 percent of their function. The symptoms seen include excessive drinking and urinating together with other signs such as anemia and nausea relating to the buildup of toxins. At this stage, by limiting protein, calcium, and phosphorus in the diet of these patients, the progression of renal disease may be slowed but it most certainly cannot be halted.
• The Third Stage Of Chronic Kidney Failure
The third stage of chronic kidney failure is where the loss of kidney function is between 90 and 95 percent. By now the kidneys are so damaged they are almost unable to function. At this stage, treatment by dialysis or transplantation is necessary for survival.
The role of excessive protein in kidney failure
It is generally agreed amongst veterinary experts that high protein diets are not in themselves a cause of either acute or chronic kidney failure. It does appear, however, that where there is pre-existing kidney damage, a high protein diet will help to further that damage. That is why diets to treat kidney failure must be low in protein (and phosphorus and calcium and possibly sodium), but diets to prevent kidney disease do not have to be limited in protein.
Looking for clues
Let me now return to your letter. If we look at the lifetime diet of Hobo, we find that for seven years Hobo had consumed grocery store dry dog food. Sadly, according to lectures presented at Sydney University in 1998 by the experts at Hills Science diets, this is a well-known cause of chronic kidney failure.
Hobo’s new diet appeared to be raw meat, and this was fed for two weeks. Unfortunately we know little about this diet except that it was raw meat. We do not know what sort of meat, how clean or how contaminated it was, whether bones or supplements or anything else was fed. All we have been told is that it was a raw meat diet.
What we do know however is that, very sadly, Hobo passed away at the end of this two week period. The question is, what caused Hobo’s death? Was it kidney failure, and if so, what was the cause of the kidney failure? Is it possible that, as the letter said, “his kidneys could not process the high protein food”? In support of this, it was proposed that … “Although dogs descend from wolves, some of them may have lost the ‘gene’ for eating either high protein foods or contaminated foods.”
First, the ability to consume either high protein foods or contaminated foods is not controlled by a single gene. Both of these traits are multifactorial in origin. The ability to safely consume high protein foods and contaminated foods can, however, be compromised or even destroyed by feeding an inappropriate diet such as grocery store dry dog food over a long period of time. This is because, again, over time, grocery store dry dog food will – via a variety of mechanisms involving malnutrition and periodontal disease – cause kidney failure, which will leave the dog susceptible to a high protein diet. That is, under conditions of an already damaged set of kidneys, feeding a high protein diet will cause further kidney damage.
And with respect to contaminated foods – the long-term effects of malnutrition are a depleted immune system. A poorly functioning immune system is the only reason a dog cannot safely eat contaminated food. The ability to safely consume contaminated food has been destroyed.
Note that when we do have a dog with kidney failure, a properly formulated BARF diet which is low in protein, calcium, phosphorus, etc., works absolute wonders.
Don’t blame meat
If we accept that Hobo did indeed die from kidney failure, the first question is – was it acute or chronic?
If Hobo died from acute kidney failure, then it is clear from the above discussion that the cause was not due to a sudden increase in protein in the diet. That is not to say that we can rule out this particular raw meat diet as a cause of death. However, we would need a lot more information to make any further judgment on that. What we can say with certainty is that if there was acute kidney failure, it was not due to a high protein diet.
If Hobo died from chronic kidney failure, it means that Hobo’s kidneys were already in a perilous state of health when his diet was switched from store bought dry food to raw meat. That is, between 80 and 90 percent of his kidney function must already have been destroyed. That leaves the question open as to what might possibly have caused that kidney destruction.
If there was a dietary cause of that 80-90 percent kidney destruction, there is only one possible culprit here, and that is certainly not the new all-meat diet. It is possible however, although highly unlikely in such a short period of time, that the new all-meat diet could have pushed Hobo over the edge. In other words, on the available evidence, which is scant, there is no way that the new all-meat diet caused a death that was not about to happen anyway.
On the available evidence, it is clear that the underlying cause of Hobo’s untimely death was most likely to be related to a lifetime spent eating inappropriate food. It is possible that some aspect of the new food could have been the final straw in the process however. On that basis it would be very wise not to feed Princessa on the grocery store dry food. On the other hand, if she is to be fed properly, it is imperative that appropriate advice be sought regarding healthy sources and correct formulation of an evolutionary diet to ensure her maximum health into the future.
Dr. Ian Billinghurst is an Australian veterinarian and author of Give Your Dog A Bone and Grow Your Pup With Bones. Dr. Billinghurst’s books can be purchased through dog book catalogs or directly from his practice. Click here for more information.