Pet Food for Dogs and Cats Requiring a Limited Protein Source Diet

Some pets have sensitivities to certain types of foods. Vetdiet® natural dog food and cat food provide pet food options with a limited protein source.

What is a food sensitivity?

Food sensitivities can be non-immune or immune mediated. Non-immune mediated food sensitivities are called food intolerance. These can be a reaction to chemicals such as caffeine sensitivity, toxins from food poisoning, or a metabolic dysfunction such as lactose intolerance. Most food sensitivities in dogs and cats are immune mediated which occur when the immune system identifies a food protein as foreign.

Immune Mediated Food Sensitivities

A food sensitivity can be associated with several ingredients, including proteins, lipoproteins, glycoproteins, lipopolysaccharides and carbohydrates. The reason an immunological response against a specific protein occurs in certain individuals is not fully understood, but may result from changes in digestive tract function. The digestive system breaks down proteins in the diet into smaller fragments, either peptides or single amino acids, before absorbing them through the intestinal wall and into the blood stream. However, smaller proteins that are more resistant to digestion may pass into the circulation. Also, if the intestinal wall is compromised, an increase in gastrointestinal tract permeability could allow proteins into circulation that would otherwise not be absorbed. Therefore, a decrease in digestive function or increase in gut permeability could introduce proteins into circulation that may initiate an immune response.

Signs of Food Sensitivity

Dermatological signs of food allergies include non-seasonal pruritus (severe itching) that is generalized, or on the face, abdomen, feet, or rear half of the body. Other signs include otitis externa (inflammation of the ear), erythema (red patches on the skin), alopecia (hair loss); and secondary infections including staphylococcal pyoderma. Gastrointestinal signs include vomiting, diarrhea, weight loss, loss of appetite, abdominal discomfort, and more frequent bowel movements. Additional respiratory or neurological signs may be present as well.

What proteins are commonly associated with food sensitivity?

Many food sources have been reported in the literature as potentially containing allergens. However, it is often difficult to isolate the exact source of the allergen in a mixed diet, therefore reported allergens may not accurately represent actual allergens. For example, it is often perceived that food additives are causing an allergic reaction. However, food additives are not typically proteins or carbohydrates and are not of a size typically associated with eliciting an immune response. Among research studies, the most commonly reported food ingredients associated with allergies are beef, dairy, wheat and egg for dogs, and beef, dairy, fish and lamb for cats.¹ Animals that have food allergies tend to have allergies to several food components at once making it difficult to identify the ingredient causing the sensitivity.^{2, 3}

Veterinarian Diagnosis of Food Sensitivities

Environmental factors, such as fleas and chemical irritants, are by far the most common cause of skin problems in pets. Therefore, it is critical to eliminate the possibility of the presence of these factors before considering a food allergy. An elimination diet, with subsequent re-challenge with the original diet, is the only way to confirm a diagnosis of food allergy or intolerance in pets. During an elimination diet, a single novel protein source and single novel carbohydrate source should be fed for a minimum of 8 to 10 weeks to eliminate the allergen from the diet. Sustained elimination of the allergen or aggravating food component from the diet is essential. This may be achieved by feeding a homemade diet, hydrolyzed protein diet, or a diet containing a limited protein source. However, homemade diets often have nutrient deficiencies if not carefully prepared, and therefore should not be fed for extended periods of time. Hydrolyzed proteins are smaller protein units (or peptides) that will not trigger an allergic response in the immune system. This is achieved by breaking down large protein molecules into smaller protein peptides by prolonged boiling or using an enzyme such as the pancreatic protease enzyme to stimulate the naturally occurring hydrolytic process. If clinical signs of an allergy or intolerance are reduced by the elimination diet, confirmation that the elimination diet was working can be achieved by re-feeding the original diet or individual protein sources to determine if itching resumes. Once allergens are identified for an individual pet, the best option may be to feed formulas that contain novel protein sources and limited carbohydrates and avoid formulas that contain common allergy offenders such as beef, dairy and wheat.

What Is a Limited Protein Source Pet Food?

As mentioned earlier, food sensitivities can be associated with several ingredients, including proteins, lipoproteins, glycoproteins, lipopolysaccharides and carbohydrates. Most food allergies are associated with proteins. All proteins are potentially allergenic, and repeated exposure to a protein increases the chances of developing a hypersensitivity or immune response. Therefore, foods with a limited protein source may be beneficial for pets with food sensitivities. A limited protein source pet food uses a minimal amount of protein sources. Additionally, these are novel protein sources, meaning they have not been fed to a particular animal. This may be different for each individual animal, depending on their nutritional history. A limited protein source food with a minimal variety of proteins will reduce the chances that the food contains a potential allergen. Vetdiet® offers two different limited protein source dog foods which are targeted for skin and stomach health. Our Skin and Stomach Health Lamb and Rice Formula uses only animal protein from lamb and lamb meal, and does not use animal fat or natural flavors derived from animal protein. Our Skin and Stomach Health Salmon and Pea Formula uses only fish protein and no other animal ingredients. This formula is also formulated with potatoes and sweet potatoes as the primary carbohydrate source for those dogs that may need a more easily digested carbohydrate. For kittens and adult cats, Vetdiet® offers a Skin & Stomach health Salmon and Sweet Potato Formula. This formula uses fish protein from salmon and menhaden and primary carbohydrates from sweet potatoes and potatoes.

Additional Tips

When feeding an elimination diet to diagnose food allergies or a limited protein source diet to avoid allergenic foods once a diagnosis is made, it is important to consider treats that do not interfere with the overall goal of the diet. Table scraps should be avoided and treats should be matched to the novel protein and carbohydrate sources of the main diet. Additionally, foods or treats used to conceal medications should contain novel protein and carbohydrate sources.