Adverse food reactions (AFRs) in dogs and cats typically manifest with cutaneous or gastrointestinal clinical signs. Although AFRs can be managed with an appropriate diet, choosing an appropriate diet to use in a diagnostic diet trial can be complicated. This article provides an overview of hydrolyzed and amino acid\u2013based diets and a guide to options for diagnostic diet trials and long-term management of AFRs.<\/p>\n
Take-Home Points<\/strong><\/p>\n \u201cLet food be thy medicine and medicine be thy food.\u201d This saying, attributed to Hippocrates, could also be the answer to managing patients with adverse food reactions (AFRs). AFRs, which are divided into food allergy or hypersensitivity (immunologic) or food intolerance (nonimmunologic) reactions, are typically characterized by either gastrointestinal (GI) signs such as inappetence, vomiting, bloating, and diarrhea or cutaneous signs such as pruritus, erythema, and altered hair growth in dogs and cats. AFRs can be clinically managed with a well-tolerated diet, often resulting in fewer medications needed to treat secondary infections or minimize clinical signs and, hopefully, in fewer flares and negative outcomes.<\/span><\/p>\n Diagnosis of an AFR requires a strict elimination diet trial using an appropriate diet. Such diets typically fall into 3 broad categories: veterinary therapeutic hydrolyzed protein diets, veterinary therapeutic limited-ingredient diets, and complete and balanced home-cooked diets. Each type of diet has benefits and drawbacks; the latter 2 categories require a very thorough diet history to ensure a novel protein and\/or novel carbohydrate is used. Complete and balanced home-cooked diets also require a board-certified veterinary nutritionist to formulate the diet to ensure appropriateness for the patient, as well as strict client adherence to the recipe provided (<\/strong><\/span>BOX 1<\/span><\/strong>)<\/strong>.<\/span><\/p>\n Given that completely accurate diet histories are not always possible, that successfully identifying truly novel protein and carbohydrate diets can be difficult, and that clients may not adhere to home-cooked recipes (\u201cdiet drift\u201d),1<\/sup> veterinary therapeutic hydrolyzed protein diets can be excellent tools in the clinician\u2019s diagnostic and treatment toolbox.<\/span><\/p>\n The main goal of hydrolyzing a protein is to break it down to a size that removes existing allergens, thereby avoiding recognition by patients sensitized to the intact protein.2<\/sup> Briefly, hydrolysis is a reasonably reliable way to reduce antigenicity of a protein molecule by using proteolytic enzymes to cleave peptide bonds. The degree to which the resultant hydrolysate stimulates a response depends on the site of action within the peptide chain. In a hydrolyzed protein diet, all intact proteins and larger polypeptides are ideally processed into small peptides, typically <\u200913 kDa (low\u2013molecular-weight proteins). <\/span>TABLES 1 AND 2<\/span><\/strong> list currently available commercial veterinary therapeutic hydrolyzed protein diets for dogs and cats, respectively.<\/span><\/p>\n\n
\n
Hydrolyzed Protein Diets<\/h2>\n
\n
\n Table 1<\/span> Veterinary Therapeutic Hydrolyzed Protein and Amino Acid\u2013Based Diets and Treats for Dogs<\/span><\/th>\n<\/tr>\n<\/thead>\n\n \n Diet<\/span><\/td>\n Nutrient ME, g\/1000 kcal (% ME)*<\/span><\/td>\n Nutrient, g\/1000 kcal<\/span>a<\/sup><\/td>\n Ingredient Sources<\/span><\/td>\n<\/tr>\n \n Protein<\/span><\/td>\n Fat<\/span><\/td>\n CHO<\/span><\/td>\n EPA and DHA<\/span><\/td>\n TDF<\/span><\/td>\n Protein<\/span><\/td>\n Carbohydrate<\/span><\/td>\n<\/tr>\n \n BLUE Natural Veterinary Diet HF Hydrolyzed for Food Intolerance, dry<\/span>b<\/sup><\/td>\n 72<\/span>
\n(26%)<\/span><\/td>\n37<\/span>
\n(33%)<\/span><\/td>\n123<\/span>
\n(41%)<\/span><\/td>\n1.2<\/span><\/td>\n 25<\/span><\/td>\n Hydrolyzed salmon, pea protein<\/span><\/td>\n Pea starch, potatoes, potato starch<\/span><\/td>\n<\/tr>\n \n BLUE Natural Veterinary Diet HF Hydrolyzed for Food Intolerance, canned<\/span>b<\/sup><\/td>\n 104<\/span>
\n(41%)<\/span><\/td>\n25<\/span>
\n(24%)<\/span><\/td>\n122<\/span>
\n(36%)<\/span><\/td>\n1.8<\/span><\/td>\n 12<\/span><\/td>\n Hydrolyzed salmon<\/span><\/td>\n Potato starch<\/span><\/td>\n<\/tr>\n \n Hill\u2019s Prescription Diet z\/d, dry<\/span>b<\/sup><\/td>\n 51<\/span>
\n(18%)<\/span><\/td>\n37<\/span>
\n(32%)<\/span><\/td>\n144<\/span>
\n(50%)<\/span><\/td>\nn\/a<\/span><\/td>\n 17<\/span><\/td>\n Hydrolyzed chicken, hydrolyzed chicken liver<\/span><\/td>\n Corn starch<\/span><\/td>\n<\/tr>\n \n Hill\u2019s Prescription Diet z\/d Small Bites, dry<\/span>b<\/sup><\/td>\n 51<\/span>
\n(18%)<\/span><\/td>\n38<\/span>
\n(32%)<\/span><\/td>\n143<\/span>
\n(50%)<\/span><\/td>\nn\/a<\/span><\/td>\n 17<\/span><\/td>\n Hydrolyzed chicken, hydrolyzed chicken liver<\/span><\/td>\n Corn starch<\/span><\/td>\n<\/tr>\n \n Hill\u2019s Prescription Diet z\/d, canned<\/span>b<\/sup><\/sup><\/td>\n 50<\/span>
\n(18%)<\/span><\/td>\n39<\/span>
\n(33%)<\/span><\/td>\n140<\/span>
\n(49%)<\/span><\/td>\nn\/a<\/span><\/td>\n 27<\/span><\/td>\n Hydrolyzed chicken liver<\/span><\/td>\n Corn starch<\/span><\/td>\n<\/tr>\n \n Hill\u2019s Prescription Diet z\/d Low Fat, dry<\/span>b<\/sup><\/td>\n 77<\/span>
\n(27%)<\/span><\/td>\n21<\/span>
\n(18%)<\/span><\/td>\n158<\/span>
\n(55%)<\/span><\/td>\nn\/a<\/span><\/td>\n 26<\/span><\/td>\n Hydrolyzed soy protein<\/span><\/td>\n Corn starch<\/span><\/td>\n<\/tr>\n \n Hill\u2019s Prescription Diet z\/d Low Fat, canned<\/span>b<\/sup><\/td>\n 81<\/span>
\n(28%)<\/span><\/td>\n25<\/span>
\n(22%)<\/span><\/td>\n143<\/span>
\n(50%)<\/span><\/td>\nn\/a<\/span><\/td>\n 27<\/span><\/td>\n Hydrolyzed soy protein<\/span><\/td>\n Corn starch<\/span><\/td>\n<\/tr>\n \n Hill\u2019s Prescription Diet Hypo Treats<\/span><\/td>\n 47<\/span>
\n(17%)<\/span><\/td>\n31<\/span>
\n(26%)<\/span><\/td>\n164<\/span>
\n(57%)<\/span><\/td>\nn\/a<\/span><\/td>\n 19<\/span><\/td>\n Hydrolyzed chicken liver<\/span><\/td>\n Corn starch<\/span><\/td>\n<\/tr>\n \n Purina Pro Plan Veterinary Diets EL Elemental, dry<\/span>c<\/sup><\/td>\n 69<\/span>
\n(22%)<\/span><\/td>\n27<\/span>
\n(24%)<\/span><\/td>\n154<\/span>
\n(54%)<\/span><\/td>\n0.5<\/span><\/td>\n 5.8<\/span><\/td>\n Elemental diet (individual amino acids)<\/span><\/td>\n Corn starch, tapioca starch<\/span><\/td>\n<\/tr>\n \n Purina Pro Plan Veterinary Diets HA Hydrolyzed (Vegetarian), dryb<\/sup><\/span><\/td>\n 57<\/span>
\n(20%)<\/span><\/td>\n28<\/span>
\n(24%)<\/span><\/td>\n159<\/span>
\n(56%)<\/span><\/td>\n0<\/span><\/td>\n 12<\/span><\/td>\n Hydrolyzed soy protein<\/span><\/td>\n Corn starch<\/span><\/td>\n<\/tr>\n \n Purina Pro Plan Veterinary Diets HA Hydrolyzed (Chicken Flavor), dryb<\/sup><\/span><\/td>\n 56<\/span>
\n(20%)<\/span><\/td>\n33<\/span>
\n(28%)<\/span><\/td>\n148<\/span>
\n(52%)<\/span><\/td>\n0<\/span><\/td>\n 11<\/span><\/td>\n Hydrolyzed soy protein, hydrolyzed chicken, hydrolyzed chicken liver<\/span><\/td>\n Corn starch<\/span><\/td>\n<\/tr>\n \n Purina Pro Plan Veterinary Diets HA Hydrolyzed (Chicken Flavor), canned<\/span>c<\/sup><\/td>\n 77<\/span>
\n(27%)<\/span><\/td>\n36<\/span>
\n(31%)<\/span><\/td>\n121<\/span>
\n(42%)<\/span><\/td>\n0.4<\/span><\/td>\n 48<\/span><\/td>\n Hydrolyzed soy protein, hydrolyzed chicken liver<\/span><\/td>\n Pea starch<\/span><\/td>\n<\/tr>\n \n Purina Pro Plan Veterinary Diets HA Hydrolyzed (Salmon Flavor), dryc<\/sup><\/span><\/td>\n 66<\/span>
\n(23%)<\/span><\/td>\n33<\/span>
\n(28%)<\/span><\/td>\n138<\/span>
\n(49%)<\/span><\/td>\n0.3<\/span><\/td>\n 10<\/span><\/td>\n Hydrolyzed soy protein, hydrolyzed salmon<\/span><\/td>\n Corn starch<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Diet Ultamino, dryb<\/sup><\/span><\/td>\n 46<\/span>
\n(17%)<\/span><\/td>\n42<\/span>
\n(37%)<\/span><\/td>\n125<\/span>
\n(46%)<\/span><\/td>\n0.6<\/span><\/td>\n 15<\/span><\/td>\n Hydrolyzed poultry byproducts aggregate (feathers)<\/span><\/td>\n Corn starch<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Diet Hydrolyzed Protein HP, dryb<\/sup><\/span><\/td>\n 52<\/span>
\n(20%)<\/span><\/td>\n47<\/span>
\n(43%)<\/span><\/td>\n106<\/span>
\n(37%)<\/span><\/td>\n0.8<\/span><\/td>\n 15<\/span><\/td>\n Hydrolyzed soy protein<\/span><\/td>\n Rice<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Diet Hydrolyzed Protein, loaf<\/span>b<\/sup><\/td>\n 83<\/span>
\n(23%)<\/span><\/td>\n41<\/span>
\n(34%)<\/span><\/td>\n111<\/span>
\n(43%)<\/span><\/td>\n1.3<\/span><\/td>\n 57<\/span><\/td>\n Hydrolyzed chicken liver, hydrolyzed soy protein<\/span><\/td>\n Pea starch<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Diet Hydrolyzed Protein PS, dryb<\/sup><\/span><\/td>\n 56<\/span>
\n(21%)<\/span><\/td>\n32<\/span>
\n(29%)<\/span><\/td>\n135<\/span>
\n(50%)<\/span><\/td>\n1.1<\/span><\/td>\n 20<\/span><\/td>\n Hydrolyzed soy protein, potato protein<\/span><\/td>\n Potato<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Diet Hydrolyzed Protein Moderate Calorie, dryb<\/sup><\/span><\/td>\n 62<\/span>
\n(23%)<\/span><\/td>\n32<\/span>
\n(29%)<\/span><\/td>\n127<\/span>
\n(48%)<\/span><\/td>\n0.8<\/span><\/td>\n 12<\/span><\/td>\n Hydrolyzed soy protein<\/span><\/td>\n Rice<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Diet Hydrolyzed Protein Small Dog, dryb<\/sup><\/span><\/td>\n 62<\/span>
\n(23%)<\/span><\/td>\n41<\/span>
\n(37%)<\/span><\/td>\n106<\/span>
\n(40%)<\/span><\/td>\n0.8<\/span><\/td>\n 11<\/span><\/td>\n Hydrolyzed soy protein<\/span><\/td>\n Rice<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Diet Hydrolyzed Protein Treats<\/span><\/td>\n 62<\/span>
\n(23%)<\/span><\/td>\n41<\/span>
\n(37%)<\/span><\/td>\n106<\/span>
\n(40%)<\/span><\/td>\n0.9<\/span><\/td>\n 11<\/span><\/td>\n Hydrolyzed soy protein<\/span><\/td>\n Rice<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Health Nutrition Hydrolyzed Protein Puppy, dryc<\/sup><\/span><\/td>\n 57<\/span>
\n(21%)<\/span><\/td>\n47<\/span>
\n(42%)<\/span><\/td>\n99<\/span>
\n(37%)<\/span><\/td>\n0.8<\/span><\/td>\n 12<\/span><\/td>\n Hydrolyzed soy protein<\/span><\/td>\n Rice<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Diet Urinary SO + Hydrolyzed Protein, dryb<\/sup><\/span><\/td>\n 53<\/span>
\n(20%)<\/span><\/td>\n40<\/span>
\n(35%)<\/span><\/td>\n122<\/span>
\n(45%)<\/span><\/td>\n1<\/span><\/td>\n 18<\/span><\/td>\n Hydrolyzed soy protein<\/span><\/td>\n Rice<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Diet Satiety + Hydrolyzed Protein, dryb<\/sup><\/span><\/td>\n 120<\/span>
\n(37%)<\/span><\/td>\n38<\/span>
\n(29%)<\/span><\/td>\n110<\/span>
\n(34%)<\/span><\/td>\n1.6<\/span><\/td>\n 112<\/span><\/td>\n Hydrolyzed soy protein<\/span><\/td>\n Rice<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Diet Renal Support + Hydrolyzed Protein, dry<\/span><\/td>\n 34<\/span>
\n(13%)<\/span><\/td>\n47<\/span>
\n(41%)<\/span><\/td>\n127<\/span>
\n(46%)<\/span><\/td>\n1.2<\/span><\/td>\n 16<\/span><\/td>\n Hydrolyzed soy protein<\/span><\/td>\n Rice<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Diet Gastrointestinal Low Fat + Hydrolyzed Protein, dryb<\/sup><\/span><\/td>\n 71<\/span>
\n(27%)<\/span><\/td>\n20<\/span>
\n(18%)<\/span><\/td>\n146<\/span>
\n(55%)<\/span><\/td>\n0.4<\/span><\/td>\n 17<\/span><\/td>\n Hydrolyzed soy protein<\/span><\/td>\n Rice<\/span><\/td>\n<\/tr>\n \n CHO = carbohydrate; DHA = docosahexaenoic acid; EPA = eicosapentaenoic acid; ME = metabolizable energy; n\/a = not available; TDF = total dietary fiber.<\/span>
\na<\/sup>Values provided from historical Blue Buffalo (bluebuffalo.com<\/a>), Hill\u2019s (hillspet.com<\/a>), Purina (purina.com)<\/a>, and Royal Canin (royal canin.com<\/a>) product guides.<\/span>
\nDiets are subject to change; thus, it is recommended that clinicians verify nutrient content of current products with the manufacturer.<\/span>
\nb<\/sup>Diet is for maintenance of adult dogs.<\/span>
\nc<\/sup>Diet is for growth of dogs (including growth of large-breed dogs).<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n
\n Table 2<\/span>\u00a0Veterinary Therapeutic Hydrolyzed Protein Diets and Treats for Cats<\/span><\/th>\n<\/tr>\n<\/thead>\n\n \n <\/td>\n Nutrient ME,<\/span>
\ng\/1000 kcal (% ME)<\/span>a<\/td>\nNutrient,<\/span>
\ng\/1000 kcal<\/span>a<\/td>\nIngredient Sources<\/span><\/td>\n<\/tr>\n \n Diet<\/span><\/td>\n Protein<\/span><\/td>\n Fat<\/span><\/td>\n CHO<\/span><\/td>\n EPA and DHA<\/span><\/td>\n TDF<\/span><\/td>\n Protein<\/span><\/td>\n Carbohydrate<\/span><\/td>\n<\/tr>\n \n BLUE Natural Veterinary Diet HF Hydrolyzed for Food Intolerance, dryb<\/sup><\/span><\/td>\n 93<\/span>
\n(34%)<\/span><\/td>\n41<\/span>
\n(37%)<\/span><\/td>\n99<\/span>
\n(28%)<\/span><\/td>\n1.2<\/span><\/td>\n 18<\/span><\/td>\n Hydrolyzed salmon, pea protein<\/span><\/td>\n Peas, potatoes, pea starch<\/span><\/td>\n<\/tr>\n \n BLUE Natural Veterinary Diet HF Hydrolyzed for Food Intolerance, canned<\/span>b<\/td>\n 116<\/span>
\n(45%)<\/span><\/td>\n26<\/span>
\n(25%)<\/span><\/td>\n107<\/span>
\n(31%)<\/span><\/td>\n2.5<\/span><\/td>\n 12<\/span><\/td>\n Hydrolyzed salmon<\/span><\/td>\n Potato starch<\/span><\/td>\n<\/tr>\n \n Hill\u2019s Prescription Diet z\/d Original Flavor, dryb<\/sup><\/span><\/td>\n 87<\/span>
\n(30%)<\/span><\/td>\n41<\/span>
\n(35%)<\/span><\/td>\n99<\/span>
\n(35%)<\/span><\/td>\nn\/a<\/span><\/td>\n 11<\/span><\/td>\n Hydrolyzed chicken liver, rice protein concentrate<\/span><\/td>\n Rice<\/span><\/td>\n<\/tr>\n \n Hill\u2019s Prescription Diet z\/d Original Flavor, cannedb<\/sup><\/span><\/td>\n 83<\/span>
\n(29%)<\/span><\/td>\n43<\/span>
\n(37%)<\/span><\/td>\n98<\/span>
\n(34%)<\/span><\/td>\nn\/a<\/span><\/td>\n 7<\/span><\/td>\n Hydrolyzed chicken liver<\/span><\/td>\n Corn starch<\/span><\/td>\n<\/tr>\n \n Purina Pro Plan Veterinary Diets HA Hydrolyzed, dryc<\/sup><\/span><\/td>\n 103<\/span>
\n(37%)<\/span><\/td>\n33<\/span>
\n(28%)<\/span><\/td>\n100<\/span>
\n(35%)<\/span><\/td>\n0.8<\/span><\/td>\n 16<\/span><\/td>\n Hydrolyzed soy protein, hydrolyzed chicken liver<\/span><\/td>\n Rice starch<\/span><\/td>\n<\/tr>\n \n Royal Canin Veterinary Diet Ultamino, dryb<\/sup><\/span><\/td>\n 63<\/span>
\n(23%)<\/span><\/td>\n43<\/span>
\n(38%)<\/span><\/td>\n107<\/span>
\n(39%)<\/span><\/td>\n0.9<\/span><\/td>\n 20<\/span><\/td>\n Hydrolyzed poultry by-products aggregate (feathers)<\/span><\/td>\n Corn starch<\/span><\/td>\n<\/tr>\n \n