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Does my pet really need this special food?

By: Leslie Kuczynski, VMD, DACVIM

An important part of medical management of many diseases can be dietary therapy; however, special prescription diets are higher in cost and can be less convenient to obtain that over the counter pet foods. Because of that, the question of how necessary is this special diet, often comes up. Depending on the medical condition of the pet in question, special diets are prescribed for different reasons.

Kidney-friendly, prescription renal diets

Chronic kidney disease is a common ailment of many older (and in some cases, younger) pets. An early intervention management strategy is to try a “kidney-friendly” or renal diet. These special diets are restricted in protein and phosphorus levels, both of which have been shown to help slow progression of this condition. Renal diets are also often supplemented with omega 3 fatty acids and antioxidants that provide additional benefits to the pet. In an ideal world, all pets with underlying or ongoing kidney problems would eat this type of diet. It is always worth trying the diet to see if the pet will eat it readily. However, more importantly, your pet needs to eat adequate calories to support its body. Because you cannot reason with a dog or cat that may not be feeling well due to its disease process, there are many pets with kidney disease that will turn their noses up at these special diets. If that is the case, you can ask your veterinarian about medications that can help reduce nausea, reduce acid production, or stimulate the appetite. If your pet will still not readily eat the special diet, other things to try include senior-specific dog and cat foods. Senior pet foods tend to be somewhat protein and salt restricted when compared to regular adult diets and may have some benefit. Any dog food is better than no food at all, and if your pets’ condition is worsening, bland people foods such as boiled lean chicken or beef are going to be better than not eating anything at all. Phosphorus binders are medications that can be added to a pet’s medication routine to help bind phosphorus in the diet and help lower blood phosphorus levels.

“Hypoallergenic” diets

Depending on what your pet’s primary problem is, your veterinarian may recommend a “hypoallergenic” diet. Typically, these diets are recommended in dogs and cats with ongoing skin or ear problems or with chronic gastrointestinal problems that are suspected to be related to inflammatory bowel disease. In these pets, it is suspected that a food allergy may be triggering your pet’s immune system to over-react and create inflammation against their own body – either in the GI tract or in the skin (sometimes in other areas). There are two forms of what are considered “hypoallergenic” diets. A novel protein diet is a diet that is created from a single protein source that your pet most likely has never been exposed to before. Since your pet has not been exposed to this protein, their body is unlikely to react negatively towards it. An alternate type of “hypoallergenic” diet is a hydrolyzed protein diet. In hydrolyzes protein diets, the protein source is processed to be so small that the immune system has a harder time recognizing it as a protein and therefore, a harder time over-reacting to it. There are several conditions in dogs and cats that will improve dramatically with diet change alone. One very important thing to remember when transitioning your pet to a hypoallergenic diet is that this is the ONLY diet that they can eat. These diets can be costly. If your pet is receiving any other food (table food, dog treats, cat treats, other pets’ food), the special diet is rendered useless.

Diets to prevent urinary tract stone formation

There are several types of urinary tract stones that can cause problems in cats and dogs. The most important dietary consideration when trying to prevent urinary tract stone formation is increased water consumption. Increasing your pets’ water consumption can be accomplished in several ways. Increasing the number of water bowls around the house, ensuring that water bowls are clean and refilled daily to several times daily, adding water to their dry or canned food, or trying a free circulating fountain are all some options. Diet change to a prescription diet to help prevent stone formation can also help. Many of these diets are created so that they increase your pet’s thirst and encourage them to drink more. These diets also have controlled levels of several elements – magnesium, phosphorus, and calcium – which are the building blocks of some of the more common stone types in cats and dogs. These diets often are supplemented with dietary acidifiers to help regulate urine pH, antioxidants and omega 3 fatty acids to help reduce oxidative stress and decrease inflammation. Depending on the type of stone that your pet has a propensity towards forming these diets can be both preventative and sometimes therapeutic. Please talk to your veterinarian about specific recommendations for your pet’s specific problem.

Hyperthyroid, iodine-restricted diet for cats

There is currently one diet on the market that is highly iodine restricted. This diet is intended to serve as a treatment for hyperthyroidism instead of medications or radioactive iodine therapy. This diet can be quite effective, but your cat must be fed ONLY this diet in order for it to be effective. Even very small amounts of other diets or eating this special diet out of an unwashed dish that previously contained another diet can increase the iodine content in your cat’s food to make this diet ineffective. You must have dedicated dishes for your cat to eat this diet out of. Your cat cannot eat other treats or diets that are not iodine restricted.

High protein, low carbohydrate diet for cats

Cats have a higher maintenance requirement for protein when compared to dogs. They also have specific needs for certain amino acids. Cats also have a more difficult time processing carbohydrates due to their specific metabolism. Low carbohydrate diet is a mainstay in the treatment of feline diabetes mellitus, and can sometimes help lead a diabetic cat towards diabetic remission. A high protein, low carbohydrate diet will improve insulin sensitivity and can help reduce external insulin requirements. Reduced carbohydrate load will help to reduce post-meal blood sugar concentrations which can sometimes last for many hours in a cat. High protein diets are important in cats to help maintain their normal metabolic needs but also to help maintain a lean body mass in certain disease states such as diabetes mellitus.

Gastrointestinal Diets

In cases of acute GI upset such as vomiting or diarrhea induced by viral disease or by dietary indiscretion, often a gastrointestinal friendly diet will be prescribed. These diets are highly digestible, have moderate fat levels, and have easily assimilated nutrients. They often also have a combination of soluble and insoluble fiber to help modify bowel transit time. These diets are often well tolerated and can improve clinical signs associated with a sensitive GI tract. These diets are NOT hypoallergenic.