Each stage of a dog's life prompts questions because we want the absolute best for our canine companions. When we realize our best friend is showing signs of aging, there are suddenly new questions, such as: When is my dog considered a senior canine? As dogs age, do nutritional demands change as well? Can diet help to manage physical issues like arthritis as well as behavioral changes? How do I sort through a bewildering number of choices to find the best dog food for our older dogs?
The Wanderer recently sought out Dr. Sherry Lynn Sanderson, DVM, PhD, DACVIM and DACVN from the Department of Veterinary Physiology & Pharmacology at the University of Georgia College of Veterinary Medicine to answer these questions. Dr. Sanderson's research interests include the nutritional management of diseases and the Human-Animal Bond as it pertains to benefits in older people.
The Wanderer: Is age more than just a number?
Dr. Sanderson: Yes. Other things must be taken into consideration including breed. Smaller breeds tend to have a longer life expectancy than large or giant breeds. For example, it is not uncommon to see a 15-year old Miniature Poodle, but it is much less common to see a 15-year-old Lab, as the average life expectancy of that breed is 12 years.
As with people, some dogs tend to show less signs of aging than other dogs. However, even if an older dog appears healthy, there are some changes associated with aging that may not be noticeable until they are very advanced. Like people, as dogs age, they tend to lose muscle mass. Some dogs may also have a decline in senses such as hearing and sight, and like people they can also develop cognitive dysfunction. It may initially be hard to tell if changes in an older dog's behavior are related to loss of hearing for example, or if they are developing cognitive dysfunction. It is also more common to see things like osteoarthritis in older dogs than in younger ones, and older dogs are at greater risk than younger dogs to develop diseases like chronic kidney disease and cancer. Obesity is a common problem in middle aged and some older dogs, but as dogs get increasingly up in age, we sometimes have the opposite problem of trying to keep weight on them.
The Wanderer: What ingredients should we look for to guide us toward choosing the best dog food for older dogs?
Dr. Sanderson: No matter what diet you feed your dog, it is very important to feed a complete and balanced diet, meaning all the nutrients that a healthy dog needs are provided by the diet with the exception of water.
A diet labeled as being complete and balanced for all life stages means that the diet contains all the nutrients required to meet the most energy demanding life stage of a dog, which is pregnancy and lactation. That said, there can be a tremendous variance in some of the nutrients provided by all life stage diets, and some are better than others. It is unlikely that an all life stage diet is going to contain all necessary nutrients at the appropriate amounts for an aging dog, but all diets labeled as senior do not necessarily contain the necessary nutrients in the right amounts either.
Diets listed as senior foods can also vary tremendously in composition. There are some nutrients that are very important for senior dogs to have at appropriate levels in their diet to address some of the changes that we see associated with aging. For example, it has been shown that aging dogs actually require more protein in their diet than their younger counterparts, and not all senior diets contain more protein to account for this change.
In addition to protein, other nutrients of importance include things like a prebiotic fiber, such as beet pulp or FOS (fructo-oligo-saccharide), which can help prevent the decline of good bacteria in the gastrointestinal tract that normally is associated with aging. The omega-fatty acid, eicosapentaenoic acid (EPA), is also beneficial because metabolites from this n-3 fatty acid help reduce inflammation in the body, including inflammation associated with osteoarthritis. Look for things like fish oil in the ingredients. However, things like flaxseed are not a direct or good source of EPA because they rely on the body to convert alpha-linolenic acid (ALA) into EPA, which is not very efficient in the dog.
Aging is associated with an increase in free radical production in the body, and having antioxidants in the diet is also important. More recently, the addition of medium-chain triglycerides in the diet has also been shown to improve cognitive dysfunction in dogs.
My recommendation is to feed a complete and balanced diet and try to maintain the dog's target body weight. Ideally, the best dog food for the entire life of a dog contains appropriate amounts of protein, prebiotics, n-3 fatty acids and antioxidants. If a pet owner is not currently feeding a diet with these elements, my recommendation is to change their healthy aging dog to a diet that does contain these to try to lessen some of the undesirable conditions we see associated with aging.