Limited Ingredient Diets for Dogs

It’s hard to watch a beloved dog suffer from a food allergy or sensitivity and feel powerless to help. Perhaps you’ve tried feeding your pup hypoallergenic dog food without any success to show for your efforts. Another option your veterinarian may recommend to reduce exposure to allergens or irritants is a limited ingredient dog food diet (LID), which contains a limited number of ingredients that are easy to identify.

Our extensive guide outlines what you need to know about this category of dog food so you can make an informed decision. We’ll explain what a LID diet is (it’s about more than just a limited number of ingredients), review the benefits and potential risks, and follow up with tips for selecting the best limited ingredient dog food.

What Is a Limited Ingredient Diet for Dogs?

Limited ingredient diets for dogs (LIDs) are made up of a select number of simple, identifiable ingredients. Generally, they contain one high quality protein (sometimes more) and a minimal number of complex carbohydrates sourced from highly digestible vegetables, fruits, or starches.

The protein source is typically one the dog hasn’t previously consumed (referred to as a novel protein) and not widely available in commercial dog foods. Examples of novel proteins are fish, venison, rabbit, and duck. Examples of complex carbohydrates are cooked sweet potatoes, peas, and rice.

To keep the food as hypoallergenic as possible, limited ingredient diets are free from artificial flavors, dyes, unnatural preservatives, fillers like corn and soy, and unidentifiable meat products like chicken meal or poultry.

How Limited Ingredient Dog Food Differs from Hypoallergenic Dog Food

Hypoallergenic dog food is a broad term that encompasses diets free from ingredients most commonly known to cause food allergies in dogs, including beef, chicken, wheat, dairy, and eggs. They may or may not contain a limited number of ingredients.

Both limited ingredient dog food diets and hypoallergenic dog food diets are available over the counter or with a prescription from your veterinarian.

Veterinary prescription diets are put through extensive trials and strict quality control processes, in part to prevent cross-contamination with other proteins.

Types of Limited Ingredient Dog Food Formulations

Limited ingredient wet dog food and dry food are just two available formula options. Another is a freeze-dried version, a raw ingredient diet that after being frozen, has its moisture removed. The freeze-drying process effectively preserves the vitamins and minerals, translating to a nutrient-dense diet. Because freeze-dried dog food contains raw ingredients, however, it can potentially be hazardous to dogs.

Why Some Dogs Need a Limited Ingredient Diet

While most healthy dogs don’t require a limited ingredient diet, there are times when it can be beneficial.

• Food allergies or intolerances. Limited ingredient dog food contains a minimal number of ingredients, reducing the chance of an allergic reaction, while excluding those commonly known to cause allergies. LIDS are often formulated with a novel protein, which a dog’s immune system is less likely to recognize and react to.
• Sensitive stomachs or digestive disorders. When it comes to gastrointestinal issues, the fewer and simpler the ingredients, the better. Limited ingredient diets for dogs are also formulated with ingredients that are easier to digest (like cooked peas and sweet potatoes) and omit those that can cause issues for some dogs, like gluten products.
• Chronic health conditions. Veterinarians believe diet plays a role in the development of certain chronic health conditions, including inflammatory bowel disease (IBD). With this disease, one option your veterinarian may recommend is putting your dog on a supervised elimination diet trial via a limited ingredient novel protein diet. In the case of chronic colitis, a diet containing a novel protein may sufficiently control the condition.

Always initiate a conversation with your veterinarian before switching to limited ingredient dog food or if you suspect your dog has a food allergy or other health condition. Feeding your dog a specialized diet without a proper diagnosis can worsen a situation.

Potential Benefits of Limited Ingredient Diets

Keep in mind that since limited ingredient diets for dogs are not regulated and can vary in formulation, so they may not consistently offer the following benefits. It’s best to speak to your veterinarian about the most appropriate diet for your dog’s specific health needs.

• They make it easier to identify allergens. To determine a specific food allergen, veterinarians often rely on elimination diet trials. To perform these trials, the veterinarian will prescribe either a hydrolyzed diet or a novel protein diet, which is a feature of LIDs.
• LIDs may improve skin and coat. Eliminating ingredients that cause an allergic reaction can, of course, help clear up symptoms like itchiness, redness, and inflammation. Another plus is that novel proteins (salmon and duck, for example), are also high in nutrients like Omega-3 fatty acids, which have noted benefits for skin and coat.
• They aid in digestive health. A diet formulated with a limited number of simple, easy-to-digest ingredients reduces the risk of triggering digestive upset.
• LIDs support weight management in dogs with sensitivities. Limited ingredient dog food diets are formulated without excess ingredients, some of which can cause weight gain. They also contain a high-quality protein source to keep your dog feeling fuller for a longer period of time.

Risks and Considerations

• Not all limited ingredient diets for dogs are nutritionally complete. Individual ingredients, even high-quality ones, don’t mean much unless they’re part of a complete and balanced diet. To qualify as complete and balanced, the diet must contain all the required vitamins, minerals, and nutrients a dog needs in the appropriate amounts for the given life stage. Check the label for a nutritional statement by the Association of American Feed Control Officials (AAFCO), the organization that sets pet food standards.
• Over-reliance on novel proteins can be risky. Too much or too little of any ingredient can cause nutritional deficiencies. This is especially true if the limited ingredient diet is not complete and balanced.
• LIDs may not be necessary for healthy dogs without sensitivities. Limited ingredient dog food is most commonly used for elimination trials to determine the source of the allergy. Even then, veterinarians estimate that only about 10-20% of all allergy cases can be attributed to food. If you like certain components of the limited ingredient dog diet (ingredient simplicity, for example), ask your veterinarian about standard diets that contain these features.

Limited Ingredient Diet vs Regular Dog Food

Limited ingredient dog diets are not necessarily better than standard diets. Feeding your dog a LID isn’t beneficial, after all, if those three or four ingredients have poor nutritional value. Conversely, fillers like corn and soy, which are often party of a standard dog diet, can provide some nutritional benefits. What matters most is the nutritional value and quality of the ingredients and whether they are part of a complete and balanced diet.

Here is what you might find in each type of diet:

Limited Ingredient Diet

Ingredients. Made with a minimal number of ingredients generally consisting of one (or two) high quality proteins, and up to two sources of complex carbohydrates.

Protein Sources. Often formulated with a novel protein not commonly available in standard dog food diets; examples are fish, rabbit, venison, or duck. The LID should exclude unidentifiable proteins, like poultry or meat meal.

Carbohydrate sources. Contains complex carbohydrates sourced from vegetables, fruits, or starches; examples include cooked sweet potatoes, peas, and rice.

Additives. Omits ingredients like artificial flavors and dyes, fillers, and unnatural preservatives.

Regular Dog Food

Ingredients. May contain dozens of ingredients, including multiple sources of protein and carbohydrates, as well as added vitamins, minerals, supplements, fillers, and dyes.

Protein Sources. Though it varies by manufacturer, protein sources often include chicken, beef, or fish, as well as by-product meats and meat meal options.

Carbohydrate sources. Most are formulated with cereal grains, including wheat or oats. Commercial dry dog food diets are often formulated with ingredients like soy, corn, and rice.

Additives. The diet may contain fillers, artificial flavors and dyes, and be supplemented with added vitamins like vitamins C and E (which are also used as natural preservatives), and minerals like calcium and phosphorus. It may be formulated using an artificial preservative like carrageenan.

How to Choose the Best Limited Ingredient Dog Food

Look for a High-Quality Animal Protein as the Primary Ingredient

The protein should contain all the essential amino acids your dog needs for overall health. Some good choices include fish (salmon, whitefish, and trout), lamb, turkey, duck, and rabbit.

Opt for a Single Novel Protein If Allergies are Suspected

If your veterinarian prescribes a novel protein LID diet as part of an elimination food trial, choosing a diet with one protein source makes it easier to identify the ingredient causing the reaction.

Avoid Excess Fillers or Unnecessary Additives

Some fillers may cause an allergic reaction in some dogs. If being used as part of an elimination diet trial, unnecessary ingredients can make it more difficult to identify a potential food trigger.

Match the Diet to Your Dog’s Specific Needs

To be sure your dog is receiving all required nutrients, the diet should be formulated to meet AAFCO’s standards for a complete and balanced diet. Aside from containing all the necessary nutrients in the correct amounts, it should be appropriate for your dog’s life stage.

Slowly Transition to a New Diet

To help ease the transition, veterinarians recommend switching the diet over the course of a week or so. For example, for the first two days you might feed your dog a combination of 75% of their current diet and 25% of the limited ingredient dog food.

On days three and four, you’d feed 50% of each diet, and on days five and six, 75% of the diet would be comprised of the LID. By the seventh day, the dog would exclusively be eating the new diet. Ask your veterinarian about the best approach for your dog.

When to Consult Your Veterinarian

Prior to Switching to a LID

That red, itchy skin might not even be the result of a food allergy. It could be caused by an allergy to fleas or mold or stem from something unrelated, like a hormonal imbalance. Changing the diet before consulting veterinarian can delay proper diagnosis and treatment.

Persistent Itching, GI Upset, or Other Allergy Symptoms

Keep in mind that it can take days, or even weeks, for your dog to show improvement after being placed on a new diet. At some point, however, your veterinarian may consider other dietary or treatment options if your dog is not showing progress on the LID.

While Managing Chronic Conditions

A limited ingredient novel protein diet can be helpful in treating a condition like IBD in dogs. If it’s not helping, your veterinarian may recommend switching your dog to a prescription hydrolyzed protein diet. The proteins in hydrolyzed diets are broken down into small particles, making it less likely that the dog’s immune system will recognize it as an allergen.

Work with Your Vet

Limited ingredient dog food diets can be beneficial for dogs with food sensitivities and gastrointestinal upset and are one of the diagnostic tools veterinarians rely on to determine potential food allergens. LIDs aren’t appropriate for all dogs, however, especially if the diet isn’t nutritionally complete and balanced.

We encourage you to closely observe your dog if they have a suspected food allergy and to work with your veterinarian for proper diagnosis and treatment.