The main differences are the decreased protein and increased fiber.
Felines are considered obligate carnivores, unlike some other species of animals that are omnivores such as dogs or humans.
Protein is metabolized by the kidneys. Thus, a strict carnivore's kidneys work harder than an omnivore's or a herbivore's.
The protein values are less in the active longevity formula (for 7+ years of age) than in the optimal formula (under 7 years of age) and in this particular formula, age defying (11+ years), it is even less. Again, this is to reduce the load on the kidneys. Obviously, if you have a cat diagnosed with kidney issues, you need a different diet. This formula is a preventative formula- science diet makes a Kd diet for cats with kidney disease that can be purchased through a licensed veterinarian.
All older animals, even in the best of health, but most especially animals which require high protein requirements in their optimal years (and, hence, heavier kidney function than some other species), have lessening kidney function as they age. Inadequate protein can have detrimental long term effects when dealing with a young feline. However, in senior cats, decreasing the protein content keeps the kidneys from being overworked, often leading to greater preservation of kidney function durring these later years. Normally, because felines are strict carnivores, a high protein diet is a necessity. However, our domesticated felines, often, outlive "feral" felines. As a consequence, we are left to rethink dietary issues on a "short-term ' bases for these more senior animals (they have less years ahead than behind them). It is just a consequence of the aging process. In general, most felines will develop kidney issues if they live to a very senior ages because of their "strict carnivore" design and the high protein requirements of that design.
This formula, also, has a greater fiber content. Fiber is what "slows" food in the metabolization process- allowing time for absorption of nutrients. As animals age, our metabolism is less efficient and nutrients are not as easily and efficiently absorbed. The consequence, with regard to older animals, is that 'food" passes through the digestive system processes without the nutrients being obtained from proper digestion. This is part of the reason older animals tend to lose weight and, especially, muscle mass. Increasing the fiber intake slows down the food going through the digestive system allowing the slowing and aged body time to absorb the needed nutrients.
In conclusion, I do not recommend a "Senior Diet" for a cat based just on age. Some cats may never require such a diet. A senior diet should only be considered for animals that show signs of needing a diet change.
answered 1 year, 5 months ago
7out of 7found this answer helpful.
I cannot answer your question specifically but it may have to do with protein and/or magnesium and phosphorus content. I ordered the age defying thinking it may be better for my older can with renal problems, but alas the protein % is too high.
answered 2 years, 5 months ago
3out of 6found this answer helpful.
I would avoid the Science Diet foods. Your vet is probably "old school" and is selling the food himself. For less $ than Science Diet, you can find way way better quality foods. But you need to be careful and do some research. Many "senior" foods restrict protein and fats, but as research is showing is that as cats age, they don't absorb nutrients as well, so you should actually be feeding foods with higher protein levels, and perhaps adding a quality probiotic to help with the absorption. Look at the premium foods, Blue Buffalo, Wellness, Innova, Natural Balance, etc. I'd also recommend feeding more and more wet foods, as to avoid kidney issues from cats fed dry diets all of their lives. Much cheaper than the alternative.
answered 2 years, 8 months ago
5out of 14found this answer helpful.