Though the digestive process begins in the mouth with saliva, three main enzymes produced in a cat's pancreas play a large role in digesting and absorbing nutrients. Proteins are broken down by protease enzymes. Lipase digests fats, and amylase digests starches. If your cat's enzyme production is impaired, food will not be properly digested or absorbed.
In many older cats, it becomes very important to feed a premium diet with highly digestible proteins. In mild cases of reduced enzyme production, some owners may try a nutraceutical enzyme supplement. In severe cases, a condition called pancreatic insufficiency develops, and cats require supplemental pancreatic enzymes available by prescription from a veterinarian. If you think your cat may not be digesting her food properly, talk to your veterinarian.