Today we continue to examine the other health issues targeted by the makers of senior pet food formulas.
Foods for Joint Health
While it is true that most dogs and cats with arthritic joint changes are old, it is not true that old dogs and cats are necessarily arthritic. Geriatric changes are known to occur to the cartilage tissue of joints. Age related decreases in cartilage cells also results in decreased production and secretion of certain chemicals, namely glycosaminoglycans and chondroitin sulfate. These help the articular surfaces of bending joints maintain their resilience and repair capabilities after heavy activity or trauma. Over time this increases the risk, but not the certainty, of osteoarthritis.
By supplementing geriatric foods with glucosamine and chondroitin, manufactures are targeting these natural changes. And although it is widely believed that this supplementation may help slow joint degeneration or aid those with existing arthritis, the research is not overwhelming. If one crunches the numbers, these foods contain 1/3 or less of standard doses for glucosamine and chondroitin. Do geriatrics need a special food with a supplement at sub-therapeutic doses that may or may not help arthritis? If the cost is the same as regular food than it certainly won’t hurt, but paying more is questionable.
Foods for Gastrointestinal Health
It is thought that geriatric changes in the lining of the intestines decrease the efficiency of digestion and absorption (digestibility) of nutrients from food in older animals. Research in dogs is actually mixed, with some findings indicating decreased digestibility, and others finding no differences.
In cats the research is more convincing for decreased digestibility of protein and fat with aging. Not surprisingly, however, research indicates that increased food consumption driven by decreased calorie digestibility in older cats easily offsets these changes and results in no weight loss. In other words, gastrointestinal health is not an issue for geriatric pets, or if it does exist it is easily solved by increasing portions of their regular food.
Interestingly, pet food makers add prebiotics to senior formulas as a remedy for gastrointestinal inefficiencies of geriatric pets. This actually makes little scientific sense. Prebiotics are food fibers that promote colonic health by providing food to beneficial colon bacteria. However, all the major digestion of the nutrients in the food has occurred before reaching the colon. The job of the colon is to recapture water from the fecal mass. It also absorbs “fat calories” from chemicals produced by colonic bacteria. Colon health does not equal digestive health. This supplementation is purely a marketing ploy and has little to do with geriatric needs.
Antioxidants, DHA, and EPA in Senior Pet Foods
Those of you who follow my blog know that I find the research compellingly in favor of supplementation of pet food with antioxidants and the fatty acids DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) for promoting health. The reduction of cellular damage by “free radical” or reactive oxygen molecules resulting from normal oxygen metabolism can be reduced by antioxidants such as vitamin C and E as well as zinc and iron. DHA and EPA reduce cellular damage created by the body’s immune response and help with immune mediated conditions like allergies. They also support skin cell wall health and promote improved skin and coat quality.
Senior foods typically include enhanced levels of vitamins C and E as well as EPA and DHA, with good reason. But free radical production and over-reactive immune responses are common in younger pets — yet regular pet foods contain no vitamin C and little to no EPA and DHA. So a better question to pet food makers is, why aren’t these supplements in all pet foods? If they were, then the geriatric wouldn’t need the special food and all pets would benefit from better health.
Weight Control for Senior Pets
Metabolism does slow with aging so the caloric needs are reduced in older pets. Senior diets typically have higher levels of fiber to dilute calories. This allows owners to feed more food with less calories. But there is nothing magical about the food. A slower metabolism means a need for fewer calories, not a special food. Feeding more “diluted” food simply perpetuates “portion distortion” and overfeeding.
Senior lifestyle foods are a marketing tool, not a scientific reality.
Dr. Ken Tudor