Diet plays an important role in the endurance potential of canine athletes. The Alaskan sled dog might be considered the ultimate canine athlete, sometimes pulling a sled more than 1,000 miles in subzero temperatures. Providing a well-balanced diet is essential to meet the special needs of dogs in such nutritional-stress situations. Not only should the diet fed to these dogs be high in protein, but it also should be high in fat, which serves as the major energy source for exercising muscles.
A high-fat diet can help muscles burn fat more efficiently. During sustained exercise, fatty-acid oxidation is the primary source of energy for the muscles. Increasing the efficiency of fat metabolism spares the body’s use of carbohydrates, and because most dogs have in excess of 10 to 50 times more energy stored in fat than in muscle glycogen (carbohydrate), this might boost the animal's exercise performance.
IAMS™ studies1 have shown that in trained sled dogs as in ordinary dogs, exercise performance was enhanced by switching from a low-fat to a high-fat diet (from 25 to 65% of calories from fat), as indicated by increased:
When dogs were switched back to a low-fat diet, all of these criteria decreased to their previous values.
These results indicated that by increasing the availability of fat stores and capacity to metabolize fat for energy, a high-fat diet promotes exercise endurance in canine athletes.
1 Reynolds AJ, et al. “The effect of diet on sled dog performance, oxidative capacity, skeletal muscle microstructure, and muscle glycogen metabolism.” Recent Advances in Canine and Feline Nutritional Research: Proceedings of the 1996 IAMS International Nutrition Symposium. Carey DP, Norton SA, Bolser SM, eds. Wilmington, OH. 1996. 181–198.
Antioxidants are nutrients found naturally in the body and in plants such as fruits and vegetables. Common antioxidants include vitamin A, vitamin C, vitamin E, and certain compounds called carotenoids (like lutein and beta-carotene).
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. This process is called peroxidation. Peroxidation is useful because it helps the body destroy cells that have outlived their usefulness and kills germs and parasites. However, peroxidation, when left unchecked, also destroys or damages healthy cells.
Antioxidants help prevent widespread cellular destruction by stabilizing free radicals. More important, antioxidants return to the surface of the cell to stabilize, rather than damage, other cellular components.
When there are not enough antioxidants to keep peroxidation in check, free radicals begin damaging healthy cells, which, in turn, can lead to problems. For example, free-radical damage to cells of the immune system can lead to an increased risk of infections.
Because antioxidants play a key role in minimizing damage to human cells, such as those that make up the immune system, research examined the benefits of certain antioxidants on the immune response of dogs. The results of these studies indicated that antioxidants are important in helping dogs maintain a healthy immune system.