By Dr. R.T. (Bill) Goldston, DVM -Veterinary Gerontologist
As a general rule dog foods do not need to be supplemented if the food is a high quality commercial dog food, specifically prepared for the dogs life stage e.g. pediatric, adult, senior. HOWEVER, with most senior dogs, due to aging changes that influence food absorption and digestion from the stomach, intestines, liver and pancreas; it is best to supplement their diets with higher levels of vitamins, minerals, omega 3 and 6 fatty acids, etc. Many water soluble vitamins and fatty acid supplements that are pre-added to senior foods may lose potency.
Additionally, if your senior pet has a particular organ dysfunction as, liver disease, kidney disease, etc., additional supplements may be required. Your veterinarian can guide you in making decisions on which specific supplements should be given.