The High Protein Dog Food and Kidney Disease Myth


Posted by Optimal Pet Foods | Posted in High Protein Diet, Kidney Disease | Posted on 19-10-2010

The scientific evidence that high protein diets cause kidney problems in dogs has been widely disproved by countless studies, yet this critical nutrient has continued to be demonized by well intentioned veterinarians and the general public.

The general myth is that dogs should be on a low protein food to prevent kidney problems, especially in the case of seniors.

Dogs need protein to thrive, it has even been established that protein requirements for senior dogs increase as they age. Even responsible dog food manufacturers confirm: “While it was once thought that too much protein could cause problems, any concept of reducing protein in today’s pet foods is clearly tied to reducing ingredient costs, rather than to any concern for the health of dogs and cats.”

While it is established that limiting phosphorus and sodium intake is necessary for the management of kidney failure, protein restriction does not significantly effect the progression of the disease.

Dr. Kenneth C. Bovée describes using dietary protein as a nutritional management approach in dogs suffering from kidney disease as a medical myth. The common belief that moderate and high protein diets cause kidney disease is also unsubstantiated.

“Results of the 10 experimental studies on dogs have failed to provide evidence of the benefit of reduced dietary protein to influence the course of renal failure.”

Commercially available kidney diets are highly processed foods with little in the way of meat, often contain nutrition-less fillers, additives and very high grain content. Manufacturers use least cost ingredients to increase revenue, and other than the inclusion of basic vitamins and minerals few other health promoting ingredients can be found.

“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 a catabolic state.”

Commercial kidney diets promote the loss of lean muscle mass, which further expressed by the dog’s refusal to eat the food leads to decreased quality of life.

What about carbohydrates? As it is the high carbohydrate content from cheap grains present in commercial dog foods provide little more than empty calories for energy, when left unused, they become stored as fat.

Carbohydrate laden foods increase stress on the pancreas, can lead to insulin resistance, yeast overgrowth, diabetes and obesity. The additional pesticide load on most grain crops also needs to be considered.

The fact that dogs, cats and ferrets have zero nutritional requirements for carbohydrates illustrates the point further.

Unlike carbohydrates, protein is responsible for numerous critical body and biochemical processes.  Proteins are involved in virtually all cell functions, including hormone production, tissue repair, energy production, nutrient transport and immune functions.  And contrary to poor quality protein sources, high quality protein is known to benefit kidney function.

What Causes Kidney Dysfunction?

One of the roles kidneys are responsible for is to secrete waste products from the body. We know there are many toxins, medications and substances that cause permanent injury to the kidney’s nephrons, the kidney’s “micro filters”. Unfortunately, once gone, nephrons do not replenish themselves.

While in a few cases genetics and congenital defects do play a role, there are many known factors in the complexities that contribute to kidney dysfunction and overall health issues.

Food Quality – The pet food industry  has traditionally been an outlet for the by-products and left over wastes from human food processing. As such many foods use ingredients of negligible quality, not requiring the same regulatory requirements as human food.

Many of the ingredients used in pet food are either rejected or not passed as fit for human consumption.

Most disturbingly, ingredients from the 4-D class – dead, dying, diseased and disabled animals are often included in pet foods as protein and fat sources.

Cheap, low quality proteins and grains are high in phosphorus content and produce more waste than higher quality proteins, further burdening the kidneys. High phosphorus levels lead to increased mineral deposition in the kidneys and negatively affect kidney function.

What’s more, most processed pet foods do not list phosphorus and calcium content, those that do typically only list minimums, as such many foods contain higher than desirable levels of phosphorus and calcium.

There are manufacturers that do list maximums for calcium and phosphorus. Responsible dog food manufacturers including Acana and Orijen list both minimum and maximums for phosphorus and calcium content on their guaranteed analysis labels.

While you will find that many processed dry and canned foods are high in phosphorus,  a balanced raw diet is naturally lower.

Food Toxins – In pet food can be found ingredients laced with chemicals in the forms of preservatives, pesticides, herbicides, tainted ingredients and additives that have been established as toxins or have not undergone appropriate safety testing.

Just the very act of processing pet food at high temperatures is known to create harmful by-products, including nitrosamines, which have been linked to cancer.

Nutrition – If we look outside of the specialty health food segment, the remaining pet foods on the market contain few other health promoting ingredients other than the basics required for survival. As such we have under nourished pets that are less capable of coping with environmental stresses on their bodies and organs.

Most pet foods also lack quality, fish based essential omega 3 fatty acids, which have been found to promote kidney health and prevent deterioration of kidney function.  Flaxseed and other plant sources of essential omega 3 fatty acids are often used in pet foods, however, these are typically a poor source of omega 3.

The plant form of omega 3, AHA, must be converted by the body into EPA and DHA to be usable. Unfortunately the conversion rate is very low and most carnivores are unable to convert AHA into a usable form at all.

Environment – Like us, our pet’s bodies are contending with the unnatural environment they live in, being exposed to chemicals and toxins never before encountered. Our water, air and homes all harbor dangerous chemicals and toxins that we are exposed to on a daily basis. Chemicals can be ingested from our food and water, absorbed through the skin or inhaled through the lungs.

Dehydration – This is often overlooked as a contributor to kidney disease. A seemingly unobvious problem are pets who eat the same dry, processed foods for their entire life.

When consumed, dry foods pull moisture from the body, causing a mild state of chronic dehydration, stressing internal organs including the kidneys that must work harder to perform their function.

Before the advent of dry kibble pets were eating their natural raw foods and sharing the family’s dinner, obtaining higher quantities of water from their food.

No Variety – A lack of variety may invariably lead to a build up of certain substances or expose your pet to tainted ingredients than normally would happen when using rotation feeding.

What’s more, many pet foods add high levels of salt to enhance palatability, increasing the burden on the kidneys and causing increases in blood pressure, affecting many organs including the kidneys.

The “pet food for life” concept is not for the benefit of animals, it was invented by the pet food industry to keep you on their pet food!

What About Raw Food?

Many integrative and holistic veterinarians prefer the use of raw over processed commercial diets in general. Raw food supplies the highest digestibility and nutrient assimilation possible, contains high moisture content with naturally low phosphorus and salt content.

Unlike cooked food, raw dog food still contains all the valuable enzymes, naturally occurring vitamins, minerals, beneficial bacteria and nutrients that heat processed foods lack, while supporting the requirements our pets are designed to eat.

The high water or moisture content of raw food decreases the processing burden on the kidneys, especially in animals who do not drink adequate amounts of water.

In commercially prepared raw foods found in specialty pet stores, the human grade ingredients and protein sources used are of higher quality than those found in most commercial dry foods.

Home made raw or cooked meals are other healthy options. When preparing your own home cooked or raw meals be aware that you must ensure they are nutritionally balanced. Recipe books including Dr. Becker’s Real Food for Dogs and Cats is a good place to start.

When choosing raw or cooked diets for kidney patients, be aware that it is important to limit phosphorus and salt content. High levels of phosphorus and sodium have negative impact on kidney function. Raw food naturally has lower levels of phosphorus than processed dry or canned foods.

What About Cats?

Cats are obligate or true carnivores and the general consensus is they do very well on high protein diets.

As desert animals, cats are designed to obtain the majority of their water intake from their prey. Most cats have an under developed thirst drive. Because of this, feeding a diet plentiful in water content is critical, especially in the case of renal/kidney disease. The lack of water content in cat food is also a significant cause of FLUTD, feline urinary tract disease.

A dry processed diet creates a chronic state of mild dehydration that burdens kidneys and other organs. Raw and human grade canned foods provide an optimal level of moisture and contain significantly fewer carbohydrates, more closely matching their natural diet.


Hopefully this article has shed some light on the protein issue.

We recommend you work with an informed, integrative or holistic veterinarian who supports your choice of a natural diet and can customize a healthy diet for your pet’s specific situation.

Further Reading

Read Dr. Bovée’s fully referenced white paper:

Mythology of Protein Restriction for Dogs with Reduced Renal Function

Kenneth C. Bovée, DVM, MMedSc

Department of Clinical Studies
School of Veterinary Medicine
University of Pennsylvania
Philadelphia, Pennsylvania

Pets, Protein, Dry Food and Disease

Dr. Becker’s Real Food for Dogs and Cats

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Comments (1)

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