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 |
Healthy joints and proper weight are especially important for dogs that grow to be more than 50 pounds. But not all large- and giant-breed adult dogs have the same nutritional needs. Is your dog getting proper exercise? Is she about to have puppies? Special conditions can dramatically affect your dog’s nutritional demands. Giving her a food specially formulated for her large size, life stage and activity level is the easiest way to make sure she’s getting the nutrients she needs.
To address the special needs of your large- or giant-breed dog, look for these features:
These components are key to good nutrition. Look for them in treats, wet dog food, or dry dog food, such as IAMS™ ProActive Health™ Adult Large Breed.
Joint health is a big concern for owners of large- and giant-breed dogs. A large- or giant-breed formula that contains high-quality protein can help nourish healthy joints. Vitamins and minerals help promote the production of cartilage. Also, keeping your dog at a healthy weight will help minimize joint stress.
Dogs with lower activity levels and dogs that have been neutered or spayed are all prone to weight gain. Controlling your dog’s weight is an important step toward protecting against the health effects of excess weight, such as diabetes or joint health problems. If you use a weight-management food, look for these characteristics:
Pregnant dogs have substantial nutrition requirements. Starting in the seventh week of her pregnancy, a mother dog will need to increase her energy intake up to 50% by the time she gives birth and increase it even more when she starts nursing her puppies. Because she may lose her appetite at times, it's important that she eats a nutrient-dense food. A complete, balanced puppy formula can give her the extra nutrients she needs. But avoid puppy food created for large and giant breeds; these formulas contain specially adjusted levels of energy and minerals that may not be sufficient for a pregnant or nursing dog.
Dogs who grow to be more than 50 pounds are considered mature or senior at age 5 or 6, which is earlier than small-breed dogs. So, it’s critical to make a proactive transition to a specially formulated mature diet, such as IAMS™ ProActive Health™ Mature Adult Large Breed, to help keep your dog healthy and active as she ages.

