In response to my statement, "I’ve had much better luck diagnosing and managing food allergies in dogs since I’ve started relying more on hydrolyzed foods…" that appeared over on the canine version of Nutrition Nuggets a couple of weeks ago, TheOldBroad asked the following questions:
Have you ever dealt with a cat with food allergies?
Do you think this protocol would be advantageous for felines?
The answer to the first question is, "yes." I’ve treated a number of food allergic cats during my career. The second question is trickier….
First a review. Proteins are what incite the immune system in a true food allergy, so it shouldn’t be too surprising that protein-rich foods are the primary culprits. A review of 56 cases of feline food allergies showed that beef (29%), dairy (29%), and fish (23%) were responsible for over 80% of the incidences. Carbohydrates contain some protein, but they play a lesser role. In this study, wheat was an allergen 5% and corn 7% of the time. Other recognized allergens were chicken (7%), lamb (7%), and egg (4%). Therefore, one way that pet food manufacturers have designed diets to deal with food allergies is to avoid including common allergens. Instead, they rely on unusual ingredients like duck and potato.
Another way of going about making a hypoallergenic food is to break the proteins down into such tiny pieces that the cat’s immune system no longer recognizes them as proteins and potential allergens. This is how hydrolyzed diets work.
Now on to the hydrolyzed versus limited antigen diet debate in cats. I’ve never used a hydrolyzed diet to diagnose or treat a cat that I thought suffered from a food allergy. These are fairly new products so maybe the opportunity has simply not presented itself, but in my experience, food trials in cats using limited antigen diets have always seemed to go a bit more smoothly than they do in dogs. This might be true for a number of reasons. Perhaps cats come in contact with fewer potential allergens in their diets so it’s easier to eliminate them from a limited antigen diet. Or, maybe it’s due to some inherent difference in the disease process between the two species. Whatever the reason, I’ve never had reason to suspect that a cat’s lack of response to a food trial has been caused by an inability to find ingredients to which the individual doesn’t react.
So I think I’m going to maintain the status quo with regards to diagnosing and treating food allergies in cats. I’ll rely on limited antigen diets as my food of choice, but if I ever run into a case that I think could benefit from a hydrolyzed diet, I’ll sure be happy they are there as a Plan B.
As an aside, when I was researching this article I noticed that four out of ten "limited ingredient" cat foods advertised on a major food retailer’s website mentioned that they included some type of fish on the front of their labels. That doesn’t appear to make a lot of sense based on the results of the study I cited above.
Dr. Jennifer Coates
Image: mk30 / via Flickr