Survey of Opinions About Nutritional Requirements of Senior Dogs And
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Survey of Opinions About Nutritional Requirements of Senior Dogs and Analysis of Nutrient Profiles of Commercially Available Diets for Senior Dogs Dana Hutchinson, DVM1 Lisa M. Freeman, DVM, PhD, DACVN1 2 Karen E. Schreiner, MA 2 Dawn Geronimo Terkla, MPP, Ed.D 1Department of Clinical Sciences, Tufts Cummings School of Veterinary Medicine, North Grafton, MA 2Office of Institutional Research and Evaluation, Tufts University, Medford, MA KEY WORDS: Canine, Senior, Geriatric, opinions for all nutrients evaluated. These Diet, Nutrition, Survey results highlight discrepancies between per- ABSTRACT ceived needs of senior dogs and actual diet composition. A survey containing questions regarding respondents’ background, dog ownership, INTRODUCTION and opinions regarding senior dogs’ nutri- Nutrition plays an important role in the tional requirements was completed online health of elderly people and animals. In by 1309 adults. Average nutrient analysis people, it is known that nutrient require- for calories, protein, fat, fiber, sodium, and ments change with aging.Animals have phosphorus for senior canine diets also was higher requirements for some nutrients and obtained to determine whether respondent lower requirements for others.1 As a result perceptions were consistent with actual of the changes in nutrient requirements with profiles. Of respondents who owned a senior aging, Daily Recommended Intakes (DRI) dog, 42.8% fed a senior diet. However, have separate age categories for people 51- only 33.1% of these fed a senior diet based 70 years and >70 years.2 Alterations in body on a veterinarian’s recommendation. From weight, both weight gain and weight loss, the options provided, 63% of respondents also are especially common in aging people, reported that ingredients were the most im- with accompanying changes in individual portant factor in choosing a senior dog food. body compartments.3 These changes may Most respondents answered that senior dogs be the result of a variety of factors, such as have different nutritional needs than adults reductions in energy requirements associated and that senior diets were lower in calories, with aging, reduced food intake, and concur- fat, sodium, protein, and carbohydrates. rent disease.4-7 More importantly, there is an Comparison of 37 commercial senior diets age-related loss of lean body mass in people, revealed wide variation in nutrient profiles termed sarcopenia, that is associated with which were not consistent with respondents’ increased mortality compared to those with 68 Vol. 9, No. 1, 2011 • Intern J Appl Res Vet Med. no sarcopenia.8-11 The recognition of the reduced in calories when compared to the value of maintaining optimal body weight same company’s adult maintenance diets, and adequate muscle mass with age has led but this depends upon the individual com- to research and programs involving diet pany and individual products. While this and exercise aimed at preserving lean body reduction in calories may be appropriate for mass. some senior dogs, other senior dogs actually Although it is anecdotally speculated exhibit weight loss rather than gain because that many aspects of human aging are simi- of a variety of factors, which may include a lar in dogs and that their nutritional needs decrease in appetite, difficulty prehending also change with age. There are few studies food, changes in taste or smell sensation, or investigating this issue. Some studies have increased metabolic rate resultant from other suggested that loss of lean body mass may underlying disease.19 These dogs would, also occur in dogs,12-14 but more research is therefore, benefit from a change to a diet that needed. There is at least one study docu- contains more calories per can or cup. menting increased digestibility in senior Another modification of many senior dogs compared to younger adult dogs,15 diets compared to adult maintenance diets is although another study found no difference reduced protein based on research in other in digestibility between young adult and species that high protein diets could dam- senior dogs.16 However, little research has age kidneys by increasing the workload, and been published evaluating nutrient require- that restriction would aid in preservation of ments in senior dogs. The Association of renal function.20,21 Although studies in dogs American Feed Control Officials (AAFCO), have not shown similar results,22,23 some and the National Research Council (NRC) diets marketed for senior dogs are reduced currently has no specific nutrient profiles for in protein compared to that company’s adult senior dogs and the recommended mini- maintenance food. In addition, some studies mums (for AAFCO) or minimal require- have shown that healthy senior dogs may ments (for NRC) for senior dogs are based actually have higher protein requirements on minimum levels for adult dogs.17,18 For compared to younger adult dogs.24,25 example, using the AAFCO nutrient profiles, Unnecessary restriction of protein may the minimum protein level is 51 gm/1,000 actually exacerbate loss of lean tissue as kcal whether the dog is a young adult or multiple recent human studies have docu- senior dog.17 mented a correlation between maintenance While many veterinarians and research- of lean body mass and dietary protein intake ers anecdotally believe that senior dogs in elderly men and women.26-28 The specific have different nutritional requirements when minimal and adequate protein requirements compared to adult dogs, and senior diets are of senior dogs remain unknown, but long- currently being marketed specifically for term studies investigating the effects of di- senior dog owners, further research is neces- etary protein quantity and quality on muscle sary to identify senior dogs’ true nutritional mass and overall health of senior dogs could requirements on which to base these diets. help clarify the optimal protein content for In addition, many dog owners and veteri- dogs in this age group. narians anecdotally report that they believe A variety of other nutrient modifications senior foods have specific guidelines or have been incorporated into some commer- required nutrient modifications. cial senior diets for dogs compared to adult Despite a lack of specific regulatory maintenance diets, including lower phos- guidelines for senior diets, some common phorus and sodium levels, increased fiber themes have emerged among some com- levels, and the addition of certain nutrients, mercial pet foods for senior dogs. Many such as omega-3 fatty acids, joint supple- canine senior diets are formulated to be ments, antioxidants, and other supplements. Intern J Appl Res Vet Med • Vol. 9, No. 1, 2011. 69 While the ideal diet for every senior dog reviewed and approved by the University’s is not the same, and is dependent on many Institutional Review Board. critical factors that include body condition The survey was posted online for public and underlying diseases, an evidence-based participation from October 26th, 2009, consensus on the minimal and adequate nu- to February 2nd, 2010. The survey link trient requirements are needed as a starting was advertised on a flyer posted at local point to guide recommendations for healthy veterinary hospitals, pet stores, dog parks, seniors. libraries, and grocery stores. The link was Developing minimal and adequate also distributed via e-mail to American nutrient requirements has the potential to Kennel Club area breed clubs, was posted contribute to optimizing body composition on pet-interest Facebook pages, and Craig- during aging, preventing nutrient deficien- slist, Twitter, and advertised in Your Dog cies, and ultimately, enhancing the quality Newsletter and the state Veterinary Medical of life of senior dogs. The goals of this Association Newsletter. No incentive was study were to evaluate the publics’ opin- offered for participation in the survey, and ions of senior diets for dogs and determine all responses were anonymous. whether respondent perceptions were Dogs owned by respondents were clas- consistent with current nutrient profiles of sified as “seniors” by two separate methods. commercially available diets marketed for First, respondents answered a question that senior dogs. Investigating these issues can asked if they owned a senior dog as part of help to highlight discrepancies between per- the online survey. Secondly, the oldest dog ceived needs of senior dogs and actual diet in each respondent’s household was clas- composition. This information may also be sified as senior or non-senior based on rec- used to identify important areas of client and ognized breed size (average weight) along veterinary education. with that dog’s age. For mixed breed dogs, MATERIALS AND METHODS owners were asked to provide the dog’s Part 1 body weight along with age. Body weights were assigned to most breeds using average An 18-question web-based survey was weights for the breed.29 developed containing questions regarding Breed weights not included in this list the participant’s pet ownership, opinions were obtained from the corresponding regarding senior dogs and their appropriate national breed club website associated with diets, and participants’ background questions the American Kennel Club. Classifications including sex, age, geographic location, and of respondents’ mix-breed dogs as senior/ level of education.a,b Respondents were also asked to indicate if they were a veterinar- non-senior were discarded in cases in which ian, veterinary technician, or dog breeder… owners did not