Senior Diets
There are a few facts of life that happen to us all. We pay taxes, vote for crooked and immoral politicians and we get older. Our once active and energetic working dogs eventually gray and slow down. The question is often how to change the nutrition of these aging canines to reflect the changes. First of all, we need to challenge the current thinking (notice I did not say wisdom) of many. Do dogs need less protein as they get older than what is fed in most maintenance diets? The answer is probably not. The kidney disease has pretty much been proven untrue in a couple of studies. The research done was pretty good, even though it was done on rats (No, I am not being sarcastic here; rat research is very relevant to all mammals.). I think much of the confusion exists because dogs that do have kidney impairment are put on protein restricted diets and this action has been extrapolated to healthy dogs.
The reason for the restriction with kidney impairment comes from the way the body metabolizes protein. The liver takes the protein and breaks it up for the various body functions. One of the byproducts of this process is Blood Urea Nitrogen or BUN. The primary function of the kidney is to filter out body toxins, BUN being one of the main ones, as well as to regulate body fluid balances. If we feed excess protein it is thought that the extra BUN will harm the kidneys. That case is probably not true for normal healthy dogs. Remember that old dogs are normal and healthy. The thinking that old animals are somehow sickly or on the verge of death all the time is wrong. So what is the answer to all of this?
I believe, as always, to take the broad look at things and follow common sense combined with those things we know (that is because we do not know most things). Older dogs need protein to help abate the muscle destruction process of old age (catabolism is the word for it, as anabolism is the word for muscle building. You have heard about anabolic steroids?) So over restriction will just lead to increase muscle wasting. I recommend feeding a moderate protein diet through the senior stages, which means in the 22% to 24% range. They could get by on as low as 18% but why chance it? The real important point is the quality of the protein source. As with all stages of life, you should feed the highest quality protein source that you are able. For dogs that means a good quality meat source with perhaps some eggs. The higher the quality of protein the better and easier the body can utilize the source and the less the amount of toxic byproducts produced. In other words, most marked senior foods are too restrictive in both protein and fat and may, in fact, hasten the aging process.
After saying all of that, keep in mind there are some conditions where a restricted protein diet is needed. Your veterinarian will discuss that with you and egg is usually the best source for the protein if restriction is needed. Last, but not least, is the question of when is a dog old? Good question, and there are no black and white answers. The aging process is gradual and individual. It is affected by genetics and environment and, as I have stated in the past, nutrition is the biggest single environmental factor that you can affect. (Sorry, but genetics are tamper-proof.) I can unequivocally say that through my many years as a veterinarian, I honestly can see dogs that are fed a high plain of nutrition all of their lives age much slower than those fed Senior Diets or just cheap food. Think about that for a minute. How much is a year of life worth to you? Maybe paying an extra twenty or thirty cents a pound for food? Feed your senior canine citizens the best you can find.
In closing, just a note to let you all know that I am in the final stages of a book on practical nutrition. It will be a lot like these columns and easy reading. I will keep you posted.
Gary Cotton, D.V.M.