Limited ingredient diets have been used for years to determine allergies.

While limited ingredient recipes were originally created to deal with specific food intolerances and allergies, many pet owners are now trying them because it gives them better control over their furry ones’ nutrition. We talked to Dr. Leilani Alvarez, DVM, Head of Integrative & Rehabilitative Medicine at the Animal Medical Center in NYC, to find out more about choosing a limited ingredient diet for your dog, the benefits of using one, and why you should talk to a vet before making the switch.

THK: What exactly is a "limited ingredient diet"?

LEILANI ALVAREZ: Because there is no regulation for the term "limited ingredient" on a pet food label, this can mean any variety of things depending on the food manufacturer. Typically, a limited ingredient diet (LID), as prescribed by a veterinarian, would have only one protein and one carbohydrate source, plus the necessary vitamins and minerals to make it a complete and balanced diet as regulated by AAFCO. Many companies, however, use LID to mean "few" ingredients and this can include a number of other ingredients, but typically less than five for most companies.

THK: Why might a dog benefit from a limited ingredient diet?

LA: Dogs that benefit most from a LID are those that have a food intolerance or especially if they have a true food allergy. In the case of a true food allergy, it would be best to feed only a prescription LID.

THK: Are there some ingredients that are left out of limited ingredient recipes more often? If so, what and why?

LA: Typically, beef, chicken, and dairy would be left out, as these are the most commonly reported food allergens in dogs.

THK: If I don’t know what my dog is allergic/sensitive to, would a limited ingredient diet help

LA: One must be careful not to confuse "allergic" with "intolerance". A food allergy in its true sense is caused by an inappropriate response of the body's immune system. This occurs when the body confuses a food item (usually a protein) for a foreign invader and mounts an attack on that "foreign" protein. For example, a person with a peanut allergy can have an anaphylactic allergic reaction when they eat peanuts, even though peanuts are not a real threat to the human body. Food intolerance means our body may not digest or react to a certain food very well, such an occurs commonly with dairy products due to a lack of the enzyme that breaks down lactose or due to foods that are too high in fat or fiber or other nutrient variations. This would lead to an upset stomach with symptoms such as vomiting or diarrhea, but this is not the same as an "allergy". True food allergies are actually pretty rare in animals (<10% of allergies). The most common cause of food allergies in dogs are due to protein sources (beef, chicken, and dairy) and in cats beef, fish, and dairy—NOT due to grains or carbs. If you think your pet has a food allergy, it's best to consult your veterinarian to do a food elimination trial with a prescription grade hypoallergenic diet. The reason it's important to go with prescription-grade is that many of the OTC LID are not produced to quality standards to ensure there is no cross-contamination of ingredients. There are strict regulations in place in human grade facilities (such as The Honest Kitchen). This is why labels will often say "produced in a plant shared with nuts" because even though the ingredients may be nut-free, cross-contamination can occur if the plant also makes foods containing nuts. Therefore, if your dog is truly allergic to chicken, you wouldn’t want her Salmon LID to be produced on the same equipment as chicken diets.

THK: What if my dog doesn’t have any allergies or sensitivities—can I still feed a limited ingredient recipe?

LA: Sure. Dogs with food intolerance or sensitivity may do better with a LID. Keep in mind that food intolerance is more often caused by the amount of fat, fiber, or other nutrient variations than due to a specific ingredient. So, for example, if company A makes a food containing lean beef and company B makes food containing a fattier beef, a dog may do fine with company A diet, while it may get diarrhea when it eats company B diet. The cause of the diarrhea is likely due to the extra fat in company B beef diet, NOT the beef itself.

THK: How long would my dog need to be on a limited ingredient diet before I know if it’s helping?

LA: Typically, a minimum of 8 weeks. During a food elimination trial, your pet would need to eat the specified prescription LID or home-made diet with only 1 protein and 1 carb source for a minimum of 8-12 weeks. If the allergic symptoms resolve (typically itchy skin and ear infections, but sometimes may also include vomiting or diarrhea), then after the 8-12-week period, the suspect "allergic" ingredient is added back in and we observe to see if the symptom recurs.

THK: Is there any detriment to feeding a limited ingredient diet? Is my dog missing out on something?

LA: I would say the main detriment is that if you feed exotic type LIDs of many sorts, you may be exhausting the possibility to appropriately treat a food allergy due to previous exposure. It's best to avoid these more "novel" proteins for true medical necessities in order to allow your veterinarian to have good options to treat your pet should a true food allergy arise. Also, it would be important to ensure any food you are feeding is complete and balanced. For commercial diets, you should look for the AAFCO label. The Honest Kitchen offers limited-ingredient recipes that each contain six ingredients or less, including cage-free turkey, cage-free duck, and MSC certified white fish. If you have questions not covered above, please feel free to reach out to us at questions@thehonestkitchen.com