When a dog has cancer, it can profoundly affect their body's ability to process and absorb nutrients in their food.  This is a key cause of cancer cachexia, which occurs when the body is taking in enough calories but continues to lose weight.  As dogs lose fat and muscle mass from cachexia, their ability to withstand the stress of typical cancer treaments is compromised.  Digestive enzymes, therefore, can be extremely valuable because they help the body to break down food, making it easier for the body to absorb nutrients.  This means less effort expended on processing food, and more energy that can be devoted to fighting the cancer in their body. In addition to helping to increase or maintain body weight, this improved access to calories and nutrition can also translate into increased overall energy levels.

A good digestive enzyme product should include 4 types of enzymes -- protease, cellulase, amylase and lipase.  According to Dr. Shawn Messonier, cellulase is especially important if you are adding more vegetables to your dog's diet, as this enzyme specifically helps your dog to break down plant material and release essential nutrients that are often bound by fiber. 

You'll find digestive enzymes at most pet food stores nowadays, and they are one of the safest, most beneficial and least expensive supplements you will find.  One of the most common brands is called Prozyme.  Available in powdered form, you can simply sprinkle 1/4 teaspoon of Prozyme on each meal.

Please Note: Because digestive enzymes are destroyed by heat, they are not found in the vast majority of commercial diets, and should never be added to hot or warm food or mixed with warm water.