| SENIOR DIET SUPPLEMENTS What is glucosamine and chondroitin sulfate and when should they be used? As a dog ages, the joints become less flexible, less lubricated, and more arthritic. This is observed by the owner when the pet has difficulty getting up, is stiffer climbing the steps and jumping on the bed, takes longer to walk around the yard, and is less inclined to play for a long period of time. Cartilage is a major component of a joint and is the layer protecting the end of the bones that form the joints. There is also fluid in the joint called synovial fluid that keeps the joints lubricated. Cartilage is dependent upon lubrication and nourishment from the synovial fluid. Glucosamine is an amino sugar that is used in the production of glycosaminoglycans that are needed for joint integrity and function. These agents increase joint flexibility and cushioning. Glucosamine is an important nutrient for joint support and provides the raw materials needed for joint maintenance and repair. Glucosamine is found in the synovial fluids, cartilage, tendons, ligaments, heart valves, and eye. Methylsulfonylmethane (MSM) is a source of organic sulfur, which is needed to rebuild joints and connective tissue. This mineral is added to some of the glucosamine supplements to support joint tissue. Other added ingredients may include chondroitin sulfate, manganese, Vitamin C, and brewers yeast. Recent studies recommend that dogs be started on these supplements during early middle age and continue throughout the rest of their lives. These products are safe and have no adverse reactions. Starting a dog on these products may reduce the amount of NSAIDS that may be needed at present or in future years. There has been a lot of controversy in human medicine concerning the lack of quality control of these over the counter products. Rarely did the product actually contain the amount of glucosamine that was printed on the label. Also, many manufacturers used substandard materials. In veterinary medicine, only a few products were rated by Consumer Lab has having excellent quality control. The top product listed was Cosequin which is produced by Nutramax Labratories. This product is available only through veterinarians and is not inexpensive. Your veterinarian can guide you on selecting the best product for your pet. The normal dose of glucosamine for a 50 pound dog is approximately 500 to 600 mg daily. What are antioxidants and should they be used? Antioxidants are compounds that act to stop free radicals or prevent free radical formation in the body. Free radicals are produced through normal body function, and through environmental factors such as pollution, radiation, smoke, and chemicals. The entire interaction between antioxidants and free radicals is a lengthy and complicated process, which is beyond the scope of this article. The bottom line is that antioxidants support the immune system, protect against cell damage, slow the aging process, and increase general health and well-being. The following substances are antioxidants: Vitamin E – this is an antioxidant that enhances the immune system and may help to prevent heart disease and help with allergy control. Vitamin E is synthesized only by plants and is high in vegetable oils. It is added to pet foods in the form of tocopheryl. Selenium – this is an essential trace element that acts with Vitamin E in important metabolic pathways. There is research that suggests selenium protects against specific cancers, helps cardiac function, and helps to regulate asthma. Ingredients rich in selenium include fish, eggs, and liver. This element can be found in dog food by supplements which include sodium selenate and sodium selenite. Vitamin C - this is an antioxidant that inactivates free radicals and blocks the conversion of nitrates into cancer causing substances. It is important for healthy gums and bones, fighting infection, synthesizing collagen, resisting infection, and healing tissue. Caroteniods and Flavonoids – these are compounds that are produced by plants and are strong antioxidants. They protect against the cellular damage caused by ultraviolet radiation from the sun. These ingredients are found in fresh fruits and vegetables. Vitamin A (beta-carotene) – this vitamin is needed for the growth and repair of body tissues, the maintenance of healthy skin, the protection of mucous membranes, and immune support. Zinc – this is an important trace element which may be deficient in the Siberian Husky and other northern breeds. It is important for cellular growth, cell division, and wound healing. Reproductive function is also influenced by this mineral, especially prostate function and male hormonal activity. In summary, older dogs can definitely benefit from the addition of fresh vegetables and fruits in the diets. Also, adding Vitamin C, E and A to the diets may be beneficial. Omega –3 fatty acids may also be added to the diet, which may help dogs with arthritis and skin disease. These fatty acids are found in high concentration in deep-sea fish oils such as salmon or cod liver oils. Antioxidants are found in pet foods, fresh foods, and supplements. Recent research has also indicated that some of these products can aid in the prevention of specific cancers. Kathleen Stryeski, DVM |