What exactly is a hypoallergenic diet?

Allergies are one of the more common issues that veterinarians see pets for.  Sometimes the allergy affects the gastro-intestinal (GI) tract and causes vomiting and diarrhea problems, other times it may affect the skin, ears, eyes, and anal glands causing redness and itchy symptoms where the pet may lick or scratch constantly.  

Diagnosing an allergy definitively can be a challenge since allergies can be caused by food, environmental components (we call this atopy) or sometimes even both!  Many times, your veterinarian may recommend that your pet undergo a hypoallergenic food trial to see if there may be a food-related component to your pet's symptoms.  Contrary to what many pet owners think, food allergies that result in chronic GI or skin issues are usually the result of an adverse response to a diet that the pet has been on for several months to years rather than a new treat or food.  

The idea behind a hypoallergenic diet trial, is that the pet is being fed a protein source that it hasn't been exposed to before.  For example, some of the prescription hypoallergenic diets our veterinarians commonly use at Wascana Animal Hospital are the Royal Canin Hypoallergenic, Hypoallergenic HP, Hill's d/d, or Hill's z/d. When an animal is on a hypoallergenic food trial, it is recommended that they receive only this special diet exclusively for a minimum of 12 weeks to allow time to see if the pet is responding.  They cannot have any other foods, table scraps, or treats (unless they are prescription hypoallergenic ones).  

When you are investing the time and money into such a trial as a pet owner, it is very important that you are actually receiving a certified hypoallergenic food that has been processed properly!  Unfortunately, there are pet food stores out there that claim to have "hypoallergenic" diets but these may not have been manufactured from a certifiable plant resulting in contamination of the protein sources.  Thus when pet owners try the diet and it fails, they automatically assume that that it must not have been a food allergen.  Part of the reason that true hypoallergenic diets are more expensive than many regular maintenance diets is because of the exclusive protein sources used, and the meticulous careful ways that pet food plants have to manufacture these foods to avoid contamination.  Did you know that companies that produce certified hypoallergenic diets will often manufacture their hypo diets on a specific day of the week only after all of the machine and food processing parts have been cleaned?  Some of these companies even own multiple food plants where they may have their hypoallergenic diets manufactured at a different physical location from all of their other diets to avoid contamination issues! For this reason, we recommend that you receive a food recommendation from your veterinarian when undergoing a trial; they can recommend a reliable, full-balanced hypoallergenic food option for your pet.