We frequently see dogs or cats that we feel are food allergic and owners have “tried everything”! Well you may have tried “everything” but unfortunately most owners have been misinformed largely by dog food manufacturer’s claims. “Limited ingredient” IS NOT HYPOALLERGENIC! Let’s start with what is “hypoallergenic”–it is a food that contains only 1 protein and 1 carbohydrate source, hopefully with the protein source, one that the pet has not eaten. This is known as a “novel” protein diet. The over-the-counter limited ingredient diets despite what is listed on the label, contain other ingredients. One study of 4 over-the-counter limited ingredient venison diets when analyzed showed they contained soy, poultry, and beef–all in the food, not listed on the label (we would be happy to furnish you with the abstract of this study). This is the reason why we and your veterinarian have advised you to use a prescription hypoallergenic diet-as when those were tested, they contained only what the label said-1 protein and 1 carbohydrate and NOTHING ELSE! Some owners feel that veterinarians suggest prescription diets because we “make money” using them–I wish! WE ARE HERE FOR THE HEALTH OF YOUR PET AND TO KEEP HIM/HER HEALTHY! Why would we recommend a diet we know is not correct i.e. over-the-counter “limited ingredient” diets in making the diagnosis of food allergy in your pet!?
In addition to prescription novel protein diets which are felt to hypoallergenic, protein hydrolysate prescription diets are also used as a test for food allergy. Protein hydrolysate diets take conventional protein such as chicken or soy and cleave the protein into small segments which the body no longer recognizes as chicken or soy. The bigger the size of the protein, the more likely it is to cause allergy. New diets feature amino acids which are the building blocks of protein as a diet to diagnose food allergy. Both the hydrolysate diets and amino acids (elemental diets) are available via prescription from your veterinarian.

Additionally, there is NO BLOOD OR SKIN TEST that can diagnose food allergy! The diagnosis is made by feeding a veterinarian approved cooked diet or a prescription hypoallergenic diet (as defined above) for 8-10 weeks in dogs and 4-6 weeks in cats. No other foods, treats, bones, or beef-flavored heartworm or flea preventative can be used during this time as that will set the pet back 2 weeks. So to make the diagnosis of food allergy, it is important to follow your veterinarian’s instructions for use of a prescription diet for the amount of time necessary to determine whether he/she is food allergic. Also, new evidence shows that dogs with inhalant allergies (atopic dermatitis) have less flareups when on a hypoallergenic prescription diet as we now know that some environmental pollens cross react with some foods. If many or all of your pet’s allergies can be controlled with a specific diet, why wouldn’t you do that?!

 

Raditic D, Remillard R, Tater K. ELISA testing for common food antigens in four over the counter venison diets for dogs. J Anim Physiol Anim Nutr 2011;95: 90-97.