As your dog matures, his body functions change. He might have decreased immune-system function, deterioration of skin and coat quality, and more frequent intestinal problems. So it makes sense that what a mature dog eats might also need to change.
Throughout a dog's life, a process called peroxidation occurs. This is a normal process the body uses to destroy cells that outlive their usefulness and to kill germs and parasites, but this process also can destroy or damage healthy cells. As a dog ages, the damage caused by peroxidation accumulates and, in turn, increases the risk of certain problems such as infections.
Antioxidants are naturally occurring components in the body (but also can be acquired through diet). They help maintain overall health by neutralizing the peroxidation process of cellular molecules.
Research sponsored by IAMS™ found that dogs fed a diet rich in antioxidants such as vitamin E had improved immune responses and vaccine recognition. This might be especially important for mature/senior dogs, because IAMS research has found that, as dogs age, immune responses can decrease.
Eating a complete and balanced diet with omega-3 fatty acids, such as those found in vitamin-rich fish oils, also helps rejuvenate dry skin and develop a healthy, lustrous coat.
Aging 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 (such as diarrhea). A diet with a moderately fermentable fiber source such as beet pulp can help maintain intestinal health. Beet pulp provides energy for the cells lining the intestine and promotes proper stool formation.
Different dogs show signs of aging at different times, and much of this variation is associated with size. Larger dogs generally appear mature/senior sooner than smaller dogs. The table below can show you when your dog should start a mature diet with a food such as IAMS ProActive Health™ Mature Adult.
Dog Weight and Transition to Mature/Senior Foods
| 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 | 
 
 In the past, veterinarians recommended diets for senior dogs largely based on the nutritional management of diseases common to the aging process. Research, however, has shown that special nutrition can help manage body-condition problems in aging dogs, such as obesity and loss of muscle mass. Senior dogs also benefit from special nutrition to help maintain bone and joint health.
 
Learn more about how you can help your senior dog manage common health issues associated with aging.
Senior dogs tend to gain weight, despite consuming fewer calories, due to changes in their metabolic rate. Therefore, they can benefit from eating a diet with reduced fat levels and lower caloric density than adult maintenance foods.
 
Recent IAMS™ research in dogs also indicates that L-carnitine — a vitamin-like compound made in the body from the amino acids found in red meats, fish, chicken and milk — can help reduce weight in overweight dogs by escorting fat into cellular mitochondria where it is turned into energy.
Protein is the building block of muscle tissues. It is important for maintenance of muscle tissues, muscle strength and mobility. Recent research conducted by The IAMS Company has shown that senior dogs that eat a higher-protein diet better maintain muscle protein stores. By providing optimal protein levels from muscle maintenance, we can help senior dogs continue being physically active.
 
This research is contrary to conventional opinion that senior dog foods should contain lower protein levels than adult maintenance formulas to avoid progressive decrease in kidney function. However, senior dogs fed a high-protein diet had stable renal function and a lower death rate than dogs fed a lower-protein diet.*
During the aging process, cartilage between joints often begins deteriorating. Nutritional management can help maintain healthy bones and joints and mobility in dogs in several ways:
Some pet-food manufacturers have endorsed reduced levels of calcium and phosphorus based on the belief that excesses of these minerals are harmful to the kidneys. However, research has shown that no damaging accumulation of calcium or phosphorus was found in the kidneys of older dogs fed diets containing maintenance levels of calcium and phosphorus for four years.*
 
* Finco, DR. “Effects of aging and dietary protein intake of uninephrectomized geriatric dogs.” American Journal of Veterinary Research; Vol. 55, No. 9. Sept. 1994.
