As dogs age, changes occur in the way their bodies function, so it makes sense that what they eat also might need to change. The following list of health issues might be more common in aging pets.
Decreased Immune System Function
Throughout a dog’s life, a process called peroxidation occurs. Peroxidation is a normal process that the body uses to destroy cells that outlive their usefulness and to kill germs, parasites, etc. This process, however, also can destroy or damage healthy cells. As your dog ages, the damage caused by peroxidation accumulates, which, in turn, increases the risk of certain problems, such as infections.
Antioxidants are naturally occurring nutrients that help maintain overall health by neutralizing the peroxidation process of cellular molecules. Some antioxidants, such as vitamin E, beta-carotene, and lutein, are naturally occurring nutrients.
Recent research sponsored by The IAMS™ Company found that dogs fed a diet rich in antioxidants such as vitamin E, lutein, or beta-carotene had improved immune responses and vaccine recognition. This might be especially important in senior dog care; IAMS research has found that as dogs age, immune responses can decrease.
More Frequent Intestinal Problems
Older dogs might have higher numbers of unfavorable bacteria and lower numbers of beneficial bacteria in their intestines, which can result in clinical signs of gastrointestinal problems (e.g., diarrhea).
Feeding a diet containing fructooligosaccharides (FOS), a unique fiber source that helps nutritionally maintain healthy intestinal bacterial populations, promotes growth of beneficial bacteria. Beet pulp, a moderably fermentable fiber source, also helps maintain intestinal health by providing energy for the cells lining the intestine and promoting small, firm stools.
Different dogs show signs of aging at different times, and much of this variation is associated with size. Larger dogs generally appear 'old' sooner than smaller dogs. The table below lists the age at which various groups of dogs should be transitioned to senior foods, such as IAMS™ ProActive Health™ Senior Plus.
| Weight Range | Age to Begin Transition |
|---|---|
| More than 90 lbs | 5 years |
| 51 to 90 lbs | 6 years |
| 21 to 50 lbs | 7 years |
| Up to 20 lbs | 7 years |
There’s no doubt dogs are affectionate creatures. And they have numerous ways of showing it. So what’s the deal when your furry friend comes up and gives you a big ol’ pooch smooch? Let’s take a tongue-in-cheek look into why.

Dogs are oral creatures and gather a lot of information about their surroundings through taste and smell. Maybe you’re salty after a sweaty run. Maybe you’ve got barbecue sauce on your face. “Dogs can smell a lot better than we can,” says Opens a new windowDr. Jo Gale, BVetMed CertLAS MRCVS, Senior Manager, Global Science Advocacy at Waltham Petcare Science Institute, “so they find a lot more things interesting to lick than we can.” This despite the fact dogs only have about 1,700 taste buds compared to around 9,000 in humans.
In a poll* of dog owners, IAMS™ found a large majority (75%) believe dogs lick people to offer friendliness. That’s definitely a correct assumption. Licking has been a social behavior among dogs since the days of great-great-great granddaddy wolf. 'It’s a standard canine greeting to lick others around the face,” agrees Opens a new windowJames Serpell, B.S., Ph.D., Professor of Humane Ethics & Animal Welfare at the University of Pennsylvania School of Veterinary Medicine. “Junior members of the pack will run around and lick the mouths of more senior members.” Your dog considers you part of their pack, so it’s their way of greeting and welcoming you. Or maybe you still have that barbecue sauce on your face.
In ancient Greece, dogs at the shrine of Asclepius were trained to lick patients. In the Middle Ages, Saint Roch was said to have been cured of a plague of sores through his dog’s licks. The French even have a saying, “langue de chien, langue de médecin,” which translates to, “a dog’s tongue, a doctor’s tongue.”

Don’t cancel your health insurance just yet. While dogs’ saliva does have some possible bactericidal properties against some types of bacteria, it can put you at the risk of exposure to others. Too much licking can also reopen the wound and cause further infection. With modern medicine, you’re much better off hitting the first-aid kit.
And that myth about dogs’ mouths being cleaner than humans’? Not true — both contain over 600 types of bacteria. You’re welcome for that image.
While an occasional canine kiss is “aww”-inducing, some dogs can overdo it to the point of annoyance. When this happens, the best thing to do is “completely ignore it and give no attention,” suggests Dr. Jo Gale. “When they stop, provide them with attention.” Over time your dog will learn to scale back on the smooches.
*Surveyed U.S. dog owners, age 18+
Sample Size: n=201
Fielded May 8-10, 2020