Prescription Dog Foods: Do They Really Help?

The general concept of veterinary or prescription diets is sound; it’s well-accepted by all nutrition experts that nutrient levels and ingredients can be manipulated in various ways in order to have beneficial effects on animals (including humans) with specific health conditions. We’ve known this ever since the 1930s, when veterinarian Mark Morris innovated the first diet for dogs who were suffering from kidney failure (see “The Morris Family and the Dawn of Veterinary Diets”).

Unfortunately, nearly a century later, the concept is in danger of being a victim of its success. In the past 15 years or so, there has been a tidal wave of prescription foods being brought to market. Pet food makers have been enjoying seemingly endless success by marketing foods to the owners of dogs of ever more specific descriptions – there’s a food being pitched for adult Yorkshire Terriers! there’s one for Pug puppies! – and this trend has spread to the veterinary foods.

There are so many products that even veterinarians are often confused about which food to recommend to their clients.

The development and marketing of these products got so out of hand, that in 2016, the U.S. Food & Drug Administration (FDA) created a guidance document for its staff, intended to educate them (and, sort of subversively put pet food makers on notice) about the laws that apply to these products.

Prescription Diets for Dogs Defined

There are a few differences between a prescription diet and an over-the-counter food.

Prescription diets are defined as those that are labeled and/or marketed as intended for use to diagnose, cure, mitigate, treat, or prevent diseases and are labeled and/or marketed to provide all or most of the animal’s total daily nutrient requirements by serving as the pet’s sole diet. They are meant to be marketed by and used only under the direction of a licensed veterinarian, who bears the responsibility of ensuring that the pet receiving the diet has been properly diagnosed as suffering from a disease or other health condition for which the food would constitute an appropriate treatment. A veterinarian is also expected to provide periodic assessment of how the animal has reacted to the diet and to discontinue the product when warranted.

Consumers are not supposed to be able to purchase prescription diets without a prescription, due to the potential for misusing the product and/or misunderstanding its role in the treatment of the pet’s condition.

There’s one quirky aspect of the rules regarding the labels of prescription foods: They are not allowed to include any representation that the product contained therein can be used to treat or prevent disease. Discussion of that technical information and the specific factors of the food that are therapeutic or beneficial to pets with the diagnosed condition are supposed to be limited to veterinarians only. That’s why manufacturers of these foods maintain separate websites – one for veterinarians and a separate one for pet owners – that describe their products.

Our Peeves About Prescription Dog Foods

Though we love and believe in the concept of truly therapeutic foods, we have a few peeves with prescription foods, starting with the practice of making the technical information about the products inaccessible to owners. We believe that interested owners can and should be trusted with information about how the prescription diet is supposed to affect their dogs. We also think that giving owners access to this information would also help them discern the differences – if there truly are any – between the prescription foods and non-prescription foods whose labels may also wink and hint at certain nonspecific health benefits. Over-the-counter food labels probably read as more therapeutic than prescription food labels!

Our biggest pet peeve, though, has to do with the ingredients that tend to appear in prescription diets. These foods are full of by-products!

In a way, this is a legacy of the original inventors of prescription diets, the father and son veterinarians who developed all the original diets for Hill’s Pet Nutrition. It’s unclear whether there were any nutritionally adequate dog or cat foods on the market before Dr. Mark Morris, Sr., formulated his first products. Dr. Morris graduated from veterinary school as the Great Depression dawned. There were shortages of food for humans, so you could be certain that what was left over for making into pet food was not the most appealing material. But Dr. Morris had something that few (if any) pet food makers at the time had going for him: a scientific mind, honed at the best veterinary college of its day, and knowledge about the nutritional requirements of animals. He, and his son after him, focused on meeting those requirements – proteins, fats, vitamins, and minerals – from whatever foodstuffs were at their disposal, at the right price. Nutrients, not ingredients, became the Science Diet way – and the company’s formulators defend it to this day (though the marketing people have pushed for greater inclusions of ingredients that are more appealing to consumers (“humanization” is the industry parlance).

We don’t think there needs to be a wall between these schools of nutritional philosophy. Of course the nutrients in a food are the most important thing – but why can’t they originate from less-processed ingredients?

We developed WDJ’s dog food selection criteria with the quality of ingredients as the most important factor. In prescription dog food, the factors that are responsible for the therapeutic action of the food are of the utmost importance; we can look the other way when we see powdered cellulose as a fiber source or corn gluten meal as a protein source when we know that there are other functional attributes of those ingredients that have qualified them for inclusion. (Though when lay people can’t access the rationale for the inclusion of those ingredients, it’s frustrating!)

Fortunately, change is coming – and the newly crowded veterinary-diet market affords consumers more options, even for highly specialized products.

Recommendations for Prescription Dog Food Use

We can’t (won’t) tell you which company’s prescription diets to choose for your dog; only a veterinarian can do that! But we encourage you to dig in for (and prepare to pay for) an extended conversation with your veterinarian about any prescription diets she may recommend for your dog. We’d suggest the following discussion points if your veterinarian recommends a prescription diet for your dog:

• The first thing to ascertain is whether your vet can describe what, specifically, the product offers to your dog. What are the specific attributes that are therapeutic for your dog’s condition? It’s not enough to just point owners toward a “kidney diet” any time there is a dog of any age with almost any sort of abnormal urine test result.
• Ask follow-up questions. If, in the example above, your vet suggests that her recommended “kidney diet” has lower-protein, and that your dog should be on a lower-protein food, ask her what amount of protein she thinks is suitable for your dog. Many kidney diets have protein levels that are very low, far too low for a young or middle-aged dog in the early stages of kidney disease – so low, in fact, that dogs who are fed these diets for a long time start losing muscle mass as their bodies attempt to function without enough dietary protein. It’s easy to find foods at any level of protein she thinks is appropriate, with higher-quality sources of protein than are typically used in prescription diets.
• Buy a small amount of the food for the first time. Many prescription diets are not very palatable.
• If your dog won’t eat it, don’t fall for the “He’ll eat it if he gets hungry enough” speech. If your dog is not well, going hungry will not improve matters. As soon as possible, ask your vet for a more palatable alternative.

Alternative Dog Food

Starting below, we’ve listed all the prescription dog foods currently on the market in a searchable database. We’ve included the complete ingredients list, as well as the protein and fat content, of each of the foods on this list. We strongly suggest that you compare the ingredients of all the products that are formulated for whatever condition your dog is being treated for. Then ask your veterinarian if she could investigate the technical information for your preferred product and perhaps prescribe it for your dog, too.