Reviewed by Audrey Cook, BVM&S on March 18, 2011 From the WebMD Archives
March 18, 2011 — Dog owners exposed to the ads of pet food companies touting their products as the most nutritious, safe, or appropriate for aging canines apparently are baffled about what their pets really need.
A new Tufts University survey finds that the nutritional content of dog foods marketed for old dogs varies as widely as owners’ perceptions about what their animals need for optimal health.
Researchers polled more than 1,300 people online about their perceptions about various dog foods and correlated their answers with the actual nutritional content of nearly 40 commercially available foods sold for “senior” dogs.
The survey shows that:
- 84.5% of respondents felt older dogs had different nutritional needs compared to adult dogs.
- 43% fed older dogs a “senior” diet, but only a third of them did so based on the advice of a veterinarian.
- 63% said ingredients are the most important factor when selecting a food for a senior dog.
No Set Guidelines for Old Dogs
Neither the Association of American Feed Control Officials (AAFCO) nor the National Research Council has set official dietary requirements for aging dogs. And that means that products marketed for “longevity” or mature, senior, or old dogs do not have to adhere to a standard nutritional profile, beyond minimum standards set for adult dogs by AAFCO.
Most survey respondents felt that senior dog foods were likely less energy dense, even though caloric content of foods aimed at older dogs varied widely — from 246 to 408 calories per cup.
Some dogs gain weight but others lose weight as they age, which means the large range in calories might prove problematic for owners of older dogs, Lisa M. Freeman, DVM, PhD, of Tufts Cummings School of Veterinary Medicine, says in a news release.
Choosing the Right Amount of Sodium
Most respondents also felt that food for senior dogs contained less fat, protein, and sodium, Freeman says, but all three measures also varied widely among senior dog foods sampled.
“If an owner, for example, had a senior dog with heart disease, they might be inclined to feed them a senior food, thinking that it had less sodium,” Freeman says. “Instead, they might replace a diet that had a perfectly acceptable amount of sodium for one that is considerably higher.”
Survey respondents also were unsure whether foods for senior dogs compared to products for adult dogs would contain more or less phosphorous. Phosphorous restriction may be beneficial for dogs with kidney disease, a fact most veterinarians know, but most pet owners wouldn’t.
The actual diets had a threefold difference in phosphorous content, including one that contained three times the minimum recommended by AAFCO for the mineral.
The findings suggest that the public needs to be informed about the nutritional needs of aging pets, according to Dana Hutchinson, DVM, a co-author of the study and also a Tufts researcher.
“Factors that are equally if not more important are that the food is made by a well-established company — one with at least one veterinary nutritionist or qualified nutritionist on staff — that has proven the food’s nutritional adequacy through AAFCO feeding trials and that has rigorous quality control standards,” Hutchinson says.
Nutritional Needs for Older Dogs
The findings suggest considerable confusion about the nutritional needs of aging and old dogs, and Freeman says it is important for owners to know that every “senior diet” is different and may or may not be appropriate for their pets.
“The decision to buy a certain type of food for your aging dog is an emotional one,” Freeman says. “You want to extend her life and ensure she’s healthy well into her twilight years.”
But not all dogs need a senior diet, and owners should discuss this issue with their veterinarians, because selecting the best food for dogs is important.
Dogs are like people in that one size doesn’t fit all, the researchers say. Different animals have different needs based on age, weight, and activity and metabolism levels.
It’s easy for dog owners to be confused about what to feed senior dogs for a variety of reasons, including the fact that some pet food companies classify dogs as seniors as early as 5 years of age, while others use the term for dogs over 8. This is not surprising, in part because nutritional requirements for senior dogs have not been clearly identified.
Pet owners, the researchers suggest, should consult their vets about pet diets.
The study is published in the March issue of the International Journal for Applied Research in Veterinary Medicine.