Some older dogs will benefit from supplements. Aging dogs have special nutritional needs, and some of those can be supplied in the form of supplements.
Work with your veterinarian to develop a plan to maximize the health of your dog's joints. A daily supplement containing glucosamine and chondroitin may help, especially if combined with weight control and the proper exercise plan.
A vitamin/mineral supplement is recommended if your older dog is not receiving adequate amounts through his food. This can occur if your dog is not eating a complete balanced diet. A supplement may also benefit some older animals who tend to absorb fewer vitamins, minerals, and electrolytes through the intestinal tract, and lose more of them through the kidneys and urinary tract. Finally, some older animals eat less (due to conditions such as oral disease) and may not receive their daily needs of vitamins and minerals.
A fiber product such as wheat bran may also be given to help reduce the incidence of constipation if it occurs.
Some evidence in other species suggest that antioxidants such as Vitamins A, E, and C (ascorbic acid) may play a role in protecting against some normal aging processes.
Talk with your veterinarian to determine which supplements may be beneficial for your dog.