Limited-ingredient dog food is formulated to have fewer ingredients than traditional dog foods. Although limited-ingredient dog foods are ideal for dogs with food allergies or sensitivities, they can be a healthy option for many dogs. These diets are popular with many pet owners, from those looking to support their dogs’ special dietary needs to pet owners who wish to feed their dogs simple foods that contain ingredients that are familiar and wholesome.
What Is Limited-Ingredient Dog Food?
A limited-ingredient diet (LID) generally contains one protein source (such as lamb) and one carbohydrate source (such as brown rice). These diets may have more ingredients than just a protein and a carbohydrate, but they limit added ingredients and avoid fillers that may be found in traditional dog foods, such as corn, wheat, and soy.
Limited-ingredient diet dog foods come in both dry kibble and canned forms, and some companies even offer limited-ingredient treats or freeze-dried options. Some limited-ingredient diets are sold over the counter at pet supply stores or by online retailers, while others require a prescription from your veterinarian. As long as they are labeled as complete and balanced according to the Association of American of Feed Control Officials (AAFCO) guidelines (look for this on the label), limited-ingredient diets can be fed as your dog’s sole diet.
The term “limited ingredient” is not regulated, so there’s no threshold for the number of ingredients or limitations on what types of ingredients can be included in a limited-ingredient dog food. The term also does not guarantee against multiple protein sources being used or potential for contamination with non-listed ingredients.
“Typically, diets labeled as having limited ingredients will tend to have only a single protein source and limited carbohydrates, which reduces the number of ingredients in the diet that the dog is likely to have an adverse reaction to,” says Dr. Sarah Dodd, a veterinarian who specializes in companion animal nutrition and a resident of the European College of Veterinary and Comparative Nutrition.
“The purpose of a limited-ingredient recipe is to eliminate multiple animal protein sources,” adds Jennifer Freeman, a registered veterinary technician and director of customer care and nutrition science at Natural Balance. “Many pet parents use these recipes to help narrow down what their pet may or may not be sensitive to. They can also be a great staple for everyday feeding as well.”
Limited-Ingredient Dog Food Ingredients
Depending on the brand, you can find many different types of single source proteins in a limited-ingredient dog food. These proteins may be common (for instance, chicken and beef) or they may be what is called “novel”—less common ingredients that your dog is less likely to have eaten in the past (such as venison or kangaroo).
“A limited-ingredient diet could have any protein source,” Dodd says. “Most often, however, limited-ingredient diets utilize uncommon or exotic protein sources, in an attempt to offer something that is novel to the dog.”
“Novel animal protein sources are ideal for limited-ingredient recipes,” Freeman says, “especially if a pet parent wants to feed an animal protein source that their pet has not been exposed to before.”
According to Dodd, the top dietary allergens for dogs are chicken, beef, and dairy-derived proteins. For this reason, most limited-ingredient recipes generally include meats from birds other than chickens (for example, turkey or duck), from ruminants other than cows (like bison, sheep, goats, or deer) or from fish (salmon or pollock). Dogs who have allergies or sensitivities to one source in a category may also react to other proteins in that category. Some LIDs even include plant-based proteins from soy, peas, or oats.
Carbohydrates can be nearly anything, but generally include those known to be less likely to cause sensitivities, including rice, potatoes, sweet potatoes, and oats.
Grain-Free vs Limited-Ingredient Dog Food
Limited-ingredient diets are not the same as grain-free diets. Grain-free diets are those that contain no grains, such as corn, wheat, oats, or rice. Grain-free diets use alternative carbohydrate sources like potatoes, legumes and quinoa, but they may contain multiple types of protein and carbohydrates, as well as other ingredients. Some limited-ingredient diets are also grain free, and are labeled as both grain free and limited ingredient.
Grain-free canine diets have been implicated in the FDA’s investigation of diet-related dilated cardiomyopathy (DCM), a heart condition in dogs. Consult your veterinarian before putting your dog on a grain-free diet.
Benefits of Limited-Ingredient Dog Food
For dogs with diagnosed food allergies or food sensitivities, limited-ingredient diets are key to keeping them healthy and comfortable. Veterinarians may even suggest a limited-ingredient diet to help diagnose a food allergy in a dog.
“If a dog is suspected of having a dietary allergy, oftentimes an elimination trial is performed, where all food sources are eliminated from the diet, with the exception of a limited number of ingredients, especially proteins,” Dodd says. “If the dog’s clinical signs improve, it suggests that the dog was experiencing an adverse reaction to something in the previous diet that is not present in the limited-ingredient diet.”
The vet then “challenges” the dog to the suspect ingredient by reintroducing it to the diet to see if the dog reacts. If the dog’s symptoms return, and then resolve when that ingredient is again removed, it’s safe to say the dog is likely allergic to that particular ingredient. Most diet trials last between 8-10 weeks, because it takes that long for the skin and gut cells to turn over and for the food antigens from the previous diet to be eliminated from the body.
Diagnosing food allergies through elimination trials is tricky. The food must be absolutely free from any ingredients other than those stated on the ingredients list, including traces of ingredients that result from cross-contamination. In addition, the food must be manufactured in machines that are completely cleaned in between runs of different types of food, otherwise trace antigens of other proteins and/or carbohydrates will be present in the food. For that reason, veterinarians generally use a prescription limited-ingredient diet to perform these trials. Once a dog’s allergies have been identified, the pet owner may opt to continue feeding the prescription diet the dog does well on, or try an over-the-counter diet that does not contain any of the dog’s known allergens.
Dogs with no known allergies or sensitivities can enjoy limited-ingredient diets, too. “What is more important than looking at the number or type of ingredients is looking at the nutrient profile and determining if it fits with that dog’s individual requirements,” Dodd says. “Each dog is an individual, and their specific requirements should be considered when a diet is selected, both with respect to the number and types of ingredients they may or may not tolerate, as well as the nutrient profile that would suit their health and lifestyle best.”
Always work with your veterinarian to determine the best type of diet for your dog’s nutritional needs.
Is Limited-Ingredient Dog Food Right for Your Pup?
If you’re considering making the switch to a limited-ingredient diet, talk to your veterinarian first. Limited-ingredient diets can be a great option for most dogs whether or not they have food allergies or sensitivities, but all the formulas are slightly different.
“A complete and balanced limited-ingredient diet is just as sufficient as any other complete and balanced diet in providing all the nutrients that a dog is known to require,” Dodd says. “For example, an older dog may require a diet relatively high in energy and protein to avoid age-related muscle loss, or, if prone to being overweight, they may require a diet lower in energy to avoid weight gain as their exercise tolerance and activity decreases over time.”
Your vet knows your dog and can offer specific recommendations tailored to your dog’s nutritional needs, as well as answer any questions you might have regarding what to feed, how much to feed, and how to gradually switch your dog’s diet to something new so you can avoid any stomach upset.