Antioxidants are good for your cat because they play a key role in minimizing damage to cells, including cells of the immune system.
These important, naturally occurring nutrients help maintain health by slowing the destructive oxidative process of cellular molecules. They also can be important in supporting immune responses and vaccine recognition in cats. This may be especially critical for kittens that are being vaccinated while their immune system is still developing.
Additionally, antioxidants can reverse decreases in immune-cell function for senior cats, increasing them back to healthy adult levels.
Antioxidants are nutrients found naturally in the body and in plants such as fruits and vegetables. Common antioxidants include vitamin C, vitamin E and certain compounds called carotenoids (including lutein and beta-carotene). A blend of several antioxidants in moderate amounts may be more effective than high levels of one antioxidant.
As cells function normally in the body, they produce damaged molecules called free radicals. These free radicals are highly unstable and steal components from other cellular molecules, such as fat, protein or DNA, thereby spreading the damage.
This damage continues in a chain reaction, and entire cells soon become damaged and die in a process called peroxidation. Peroxidation is useful because it helps the body destroy cells that have outlived their usefulness and kills germs and parasites. However, when left unchecked, peroxidation also destroys or damages healthy cells.
Antioxidants help prevent widespread cellular destruction by willingly donating components to stabilize free radicals. More importantly, antioxidants return to the surface of the cell to stabilize rather than damage other cellular components.
When there are not enough antioxidants to hold peroxidation in check, free radicals begin damaging healthy cells, which can lead to problems. For example, free radical damage to immune cells can lead to an increased risk of infection.
Because antioxidants play a key role in minimizing damage to cells, such as those that make up the immune system, recent research examined the benefits of certain antioxidants on the immune response of cats. The results of these studies indicated that antioxidants are important in helping cats maintain a healthy immune system.
The research also showed that each antioxidant benefits the immune system uniquely, so one antioxidant at high levels is not as effective as a group of antioxidants acting together.
| Antioxidant | Source | Function |
|---|---|---|
| Vitamin E | Plant oil extract, tocopherols | Optimizes immune system’s T-cell activation |
| Beta-carotene | Vitamin premix, corn meal, chicken by-product meal and chicken fat | Optimizes types of cells present in the blood, increases antibody levels in the blood and optimizes vaccine recognition |
Recent research also examined the effect of aging on immune responses. The findings indicate that as cats age, immune cell responses may decline. Including antioxidants in your cat’s diet can help reverse the age-related decrease in immune cell function, returning it to healthy adult levels.


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 |