What You Should Know
If your cat suffers from food allergies or inflammatory bowel disease (IBD), your veterinarian may recommend you switch him to a hydrolyzed protein diet. A hydrolyzed diet contains proteins that are broken down into tiny pieces that are easier for a cat to digest and less likely to be targeted by your cat’s immune system to cause an allergic response.
Think of dietary proteins as huge balls of yarn, says Dr. Joseph Wakshlag, professor in the sections of Clinical Nutrition and Sports Medicine and Rehabilitation at Cornell University’s College of Veterinary Medicine.
“If the ball of yarn goes into the GI tract, the immune system might recognize it as something foreign. But if I cut off one-inch pieces of yarn and deliver them to the stomach, then the body might find the small pieces too small to recognize as foreign. That is what hydrolyzing does to protein. It chops it up into little fragments the body may not recognize,” says Dr. Wakshlag.
Most allergic reactions are in response to proteins, specifically animal proteins. Since cats are obligate carnivores—meaning they must eat meat—they are exposed to plenty of animal proteins in their diets.
Cats can show an allergic response to chicken, beef, turkey, egg, soy, and milk and other dairy products, as well as less common meats like venison or duck. The wide range of potential allergens is why trying a hydrolyzed protein diet may give faster results than doing multiple dietary trials or elimination diets with different whole proteins.
Is It Right for Your Cat?
Your veterinarian won’t recommend a hydrolyzed protein diet without good reason. Both dry and wet hydrolyzed diets are available by prescription only and are fairly expensive. If these diets reduce veterinary visits and medications needed to control your cat’s symptoms, though, they may be well worth the cost.
These diets are most useful for GI and skin food allergies, says Dr. Wakshlag. While only around only 10% of skin and GI problems are food-allergy issues, Dr. Wakshlag believes they’re worth a try since a simple diet change could be an easy fix to a big problem.
Special diets can also be used for non-allergic conditions in cats. Food intolerances and sensitivities (as opposed to full-blown allergies) may respond to the diet change. The same is true for inflammatory gastrointestinal problems in cats like IBD. A major benefit to a hydrolyzed diet is that it is nutritionally balanced and complete, so it can be fed long-term.
If your cat has GI problems that will respond to hydrolyzed diets, symptoms may take up to four weeks to improve. Food-related skin allergies often take longer to respond. Most veterinary dermatologists recommend a minimum of eight weeks, preferably 12, for a dietary trial for skin conditions.
Getting Your Cat to Eat the Food
The texture and palatability of these diets may turn some cats off, but a careful, gradual diet switch can work. Remember that you can’t add anything to the diet, like enticing toppers or special treats. With a balanced and complete hydrolyzed protein diet, your cat can (and should) live happily on this food alone.
While a simple single-protein elimination diet may help isolate the cause of your cat’s problems, such a diet is often not nutritionally complete and balanced. If you feed it for any length of time beyond the actual trial, you will likely need to consult a veterinary nutritionist to come up with a balanced diet that has all the necessary nutrients your cat needs for good health. That might mean additional dietary trials when you add any carbohydrate, fat, or fiber sources if your cat’s symptoms return.
Joseph Wakshlag, DVM, PhD, DACVIM, DACVSMR, is a professor in the sections of Clinical Nutrition and Sports Medicine and Rehabilitation at Cornell University’s College of Veterinary Medicine.
