While some OTC diets may also have properties that reduce the risk of urolithiasis, if a diet has not undergone testing for its ability to alter the environment of the urine, the efficacy cannot be assumed. Likewise, in feline idiopathic cystitis, studies have shown stress management and moisture content of food is most helpful in disease management, which is certainly not restrictive to veterinary therapeutic foods.6
Many disease conditions require individual assessment as to whether a patient’s specific set of problems requires qualities in a diet that are not available in OTC foods (e.g., obesity, gastrointestinal (GI) disease, liver disease, etc.).
Table 1: Diseases that May Require Nutrient Profiles Outside AAFCO Requirements
||Nutrients of Concern
|Chronic Kidney Disease
||Phosphorus, Protein (Moderate-Severe Disease)
|Cystine or Urate Urolithiasis
||Amino Acids, Nucleotides
Clinical Considerations to Discuss with Every Client
Successful nutritional management depends on managing expectations and open communication with clients about what veterinary therapeutic diets can and cannot provide.
Dietary management must be distinguished from medical management, in which a medication can have a direct effect based on dosage. A common misconception among pet owners is that feeding a certain diet will either cure a disease or prevent a recurrence of disease.
For instance, many pet owners get upset if diets formulated to reduce the risk of urolithiasis do not completely prevent stone recurrence. Although they have special processing and formulation to achieve a certain environment in the urine, these products can only reduce the risk of stone formation or sometimes even simply reduce the frequency, and should never be promoted as a cure that will prevent all future stone formation.
In some instances, strict adherence to a dietary plan is necessary for the diet to have any beneficial effect. For example, a dietary trial for adverse food reactions cannot be successful if foods other than the protein of interest are given to the pet, which can confuse the diagnosis.
If pet owners are not counseled that items such as rawhides, flavored heartworm medication or toothpaste have antigens, they may not understand why the test or treatment is ineffective. This author routinely sees pet owners feeding hydrolyzed veterinary therapeutic diets mixed with standard commercial treats, other commercial diets or home-prepared meats. Additionally, iodine-restricted diets intended to treat hyperthyroidism have no benefit if patients have access to other foods containing iodine.
Adherence is most successful when clients understand what the purpose of a veterinary therapeutic diet is, how it is affecting their pet’s condition, and how the consequences of non-adherence will affect their pet.
Taking the time to understand a client’s perspective can provide clues to potential challenges in adherence. This can include inquiring if all the members of the household understand and can comply with the plan, and if the client can afford the cost in the long term, if necessary.
If adherence with a veterinary therapeutic diet appears to be an issue, alternatives should be discussed. For instance, in the example of dental disease, pet owners can be directed to the Veterinary Oral Health Council (VOHC) website (www.VOHC.org), which hosts a list of products, veterinary therapeutic diets, and OTC diets that have been shown in studies approved by the VOHC to reduce tartar or plaque and have a minimum level of safety.
Table 2: Top Mistakes to Avoid When Using Veterinary Therapeutic Diets
1. Ignoring Calories or Nutrients in Treats
Almost all pet owners give treats.7 While some veterinary therapeutic diets come in treat forms, not all do, and pet owners may have special treats they feel they can “sneak in” and not affect treatment. Discussing treat options that meet nutritional goals (and when treats of any kind are not advised) will help increase adherence.
2. Medication Administration
When providing a dietary history, many pet owners do not consider foods they use to give medication or dietary supplements as part of their pet’s diet and may not report these to veterinarians. Over 60 percent of pet owners use food to give medication7—food that may not meet the patient’s nutritional goals. Discussing options will increase adherence to the plan.
3. Interchanging Flavors and Forms
Canned and dry versions of the same veterinary therapeutic foods may have drastically different nutrient profiles. For example, while a canned version of a food may be 150 calories per can, the dry version may be 500 calories per cup. Likewise, nutrient levels such as fat and protein, and micronutrients such as sodium and phosphorus may differ significantly between flavors and dry or canned versions. This inadvertent switch without attention to nutrient changes can have serious consequences in a disease such as diabetes, in which consistency is critical to management.
4. Selecting a Veterinary Therapeutic Diet Solely Based on Marketing
Selecting a veterinary therapeutic diet should be based on the nutrient profile of a diet meeting the nutritional needs of the individual patient being examined. It may seem easy to select “a kidney diet” for any patient with renal disease, but care must be taken to look at the nutrient profile. For example, an obese cat with diabetes may benefit from a veterinary therapeutic diet formulated to be high protein and low carbohydrate, but if that diet is also extremely high in calories and will promote weight gain, it is not appropriate for that individual patient.
Clinical Considerations for Growing Pets and Multi-Pet Households
Cats and dogs have special nutrient requirements beyond the needs of adult pets until they reach full skeletal maturity (at least 1 year of age). Growing animals are more susceptible to nutritional deficiencies,8 and nutrition modification for disease management must be undertaken very cautiously.
Until skeletal maturity, cats and dogs should eat a commercial food formulated specifically to meet AAFCO guidelines for growth or one that has undergone AAFCO feeding trials in growing animals. Especially in diseases where nutritional management contradicts the needs of growing animals (e.g., urolithiasis, kidney disease), a board-certified veterinary nutritionist should be consulted to properly formulate a nutritional plan (www.ACVN.org).
Pet owners often ask if they can feed all pets in the household the same food and if the veterinary therapeutic food is “safe” for healthy pets. In some situations, this may be the case, especially if the food otherwise has been formulated to meet AAFCO guidelines or undergone AAFCO feeding trials. However, it should never be assumed that all other pets in the house are healthy.
In many instances, it may be appropriate to feed a healthy pet a veterinary therapeutic diet (e.g., most veterinary therapeutic GI diets, hydrolyzed or limited antigen diets), though it is prudent to warn owners of the cost of this convenience and discuss challenges to adherence.
Most veterinary therapeutic diets formulated for dental disease, GI disease, diabetes, and adverse food reactions are likely to meet the needs of healthy dogs and cats, but each diet should be individually assessed to ensure it is appropriate for each patient it is being recommended to.
Case Example: Nutritional Plan to Reduce the Risk of Urolithiasis
Ollie is a 4-year-old, neutered male Chihuahua with a history of three surgeries for calcium oxalate uroliths in the past two years. A physical exam revealed Ollie had a body condition score of 9/9 at 15 pounds with normal muscle condition score. Before his urolithiasis, Ollie had a 6/9 body condition score at 12 pounds.
His most recent urinalysis revealed calcium oxalate crystals and a urine-specific gravity of 1.040. He was referred for a nutritional consultation for a home-cooked diet because his current therapeutic diet “didn’t work” and he had gained 3 pounds in the past two years.
A diet history initially revealed an appropriate prescription, canned urinary tract health diet at four tablespoons per day (approximately 122 kcal/day). However, more probing and a full dietary history revealed much more:
- Dog biscuit, medium: one/day (45 kcal/day)
- Meaty treat: part of one/day (estimated 66 kcal/day)
- Small bite treats: three to four/day (48 kcal/day)
- Rawhide shoe-shaped treat (or chew): three/day (estimated 225 kcal/day)
Ollie's Dietary Supplements:
When this was all added up, Ollie was receiving 500 kcal/day (1.7 x resting energy requirement for his current weight = 300 kcal/day), and only 25 percent of his daily calories were coming from the main prescribed veterinary therapeutic diet.
On further discussion, the owners had no idea treats should be discouraged, that rawhides had calories, or that feeding items other than the veterinary therapeutic diet would make it less effective.
Though a weight loss plan was not a priority at that time, it was decided with the owners to select a veterinary therapeutic diet formulated to reduce the risk of urolithiasis with lower calories and higher protein than the current diet to help aid in weight management.
- Ollie was fed one can/day of an appropriate lower calorie urinary diet to provide 326 kcal/day.
- In addition, treats were discussed, as the pet owners insisted that Ollie needed something to chew on.
- An alternative option to rawhides included putting an additional one-quarter can of the lower calorie urinary diet into a Kong® rubber toy and then freezing it, giving him something he could chew without straying from the dietary plan.
- Given the concentrated urine, water was added in one-quarter cup increments to each meal until his urine-specific gravity was less than 1.020.
Because this diet was not formulated for weight loss and Ollie was at such high risk for continued obesity and stone recurrence, biweekly weigh-ins and urine-specific gravity tests were recommended. The owners were counseled that the diet might not entirely prevent any further stones, but that it may create an environment in the urine where stones take longer to form or are less likely to form.
Through understanding this limitation and the notion that adding other foods would reduce the efficacy of the diet, the owners were much more adherent to the plan and Ollie fortunately has avoided a recurrence since this visit.
Conclusion on Veterinary Therapeutic Diets
Veterinary therapeutic diets can be an important part of nutritional management for a variety of diseases. A successful outcome often relies on managing expectations and having open communication with clients about what therapeutic diets can and cannot do, how they differ from OTC diets, and how they can specifically manage an illness.
In some cases, nutritional management with veterinary therapeutic foods is critical, and communication with clients can promote adherence to your plan and improve patient outcomes.
1. Association of American Feed Control Officials Official Publication. Association of American Feed Control Officials. 2014. Available online at www.aafco.org. Accessed January 20, 2015.
2. Churchill J. Increase the success of weight loss programs by creating an environment for change. Compend Contin Educ Vet. 2010;32(12):E1-E4.
3. Ross LA, Finco DR, Crowell WA. Effect of dietary phosphorus restriction on the kidneys of cats with reduced renal mass. Am J Vet Res. 1982;43(6):1023-1026.
4. Raditic DM, Remillard RL, Tater KC. ELISA testing for common food antigens in four dry dog foods used in dietary elimination trials. J Anim Physiol Anim Nutr. 2011;95(1):90-97.
5. Buckley CM, Hawthorne A, Colyer A, et al. Effect of dietary water intake on urinary output, specific gravity and relative supersaturation for calcium oxalate and struvite in the cat. Br J Nutr. 2011;106:Suppl: S128-S130.
6. Forrester SD, Roudebush P. Evidence-based management of feline lower urinary tract disease. Vet Clin North Am Small Anim Pract. 2007;37(3):533-558.
7. Sapowicz S, Freeman LM, Linder DE. Body condition scores and evaluation of feeding habits of dogs and cats at a low cost veterinary clinic and a general practice. Presented in abstract form at 2014 American Academy of Veterinary Nutrition Symposium, Nashville, Tenn. June 4, 2014.
8. Hutchinson D, Freeman LM, McCarthy R, et al. Seizures and severe nutrient deficiencies in a puppy fed a homemade diet. JAVMA. 2012;241(4):477-483.
About the Author
Deborah Linder, DVM, DACVN, is a 2009 graduate of the Tufts Cummings School of Veterinary Medicine. After veterinary school, she completed a one-year internship before returning to the Cummings School to complete a residency in clinical nutrition.
She is board-certified in nutrition by the American College of Veterinary Nutrition. Dr. Linder's interests include obesity management and human-animal interaction. Dr. Linder has focused her research on safe and effective weight loss strategies for pets as well as the effect of obesity on pet well-being.
She is the head of the Tufts Obesity Clinic for Animals and is a research assistant professor at Cummings School of Veterinary Medicine at Tufts University. She has recently received federal funding to launch a One Health research program that integrates human-animal interaction with health and wellness programs.
Her most recent research aims to counteract the childhood obesity epidemic in a novel method of integrating pets for sustainable healthy lifestyle change.