There are many ingredients that most of you know that are harmful to dogs (including chocolate, garlic, grapes, etc). In some homemade dog food recipes these harmful ingredients could possibly be included inadvertently, but, gum or candy? I do not know of any recipes that call for gum or candy, but some might call for some sort of sweetener. If you come across a recipe that calls for some sort of sweetener, stay away from xylitol. (See below for other alternative sweeteners)
However, there are issues with gum & candy with dog owners because sometimes people leave gum, candy, and other foodstuffs in their pets reach. Just make sure that any sugar-free gum or candy is not placed where your dog can get to it.
So what is up with sugar-free gum and candy? Here is what I know.
Xylitol is a sugar alcohol found in gum, candy, home baking and some pharmaceuticals such as chewable vitamins and throat lozenges. While xylitol is not a problem in the human body, the problem is how it reacts in a dog’s body. In your dog, it can cause a dangerous insulin surge, which in turn causes a dramatic drop in blood sugar (hypoglycemia). It is possible in higher doses to cause liver damage and coagulopathy (blood clotting).
There is some controversy on this, that is, there have been some studies that indicate that when a dog ingested xylitol that it did not suffer any consequences. I am sure that the whole process of what happens in dogs is not completely understood, so these types of results are possible. However, to be on the safe side and since there is no reason that you would have to use xylitol in your homemade dog food, then I would suggest staying away from it. Several leading organizations, including the ASPCA, also agree with this.
What about other sweeteners? If you find a need to use a sweetener in your dog food, it appears that other sugar alcohols such as sorbitol and mannitol do not have this insulin effect in dogs, however, they may cause diarrhea. Artificial sweeteners such as saccharin, aspartame, and sucralose appear to be safe as an alternative. Also, do not forget about good ole sugar if indeed you find that your homemade dog food recipes call for a sweetener.
If you have any indications that your pet has eaten xylitol, then I would call a vet immediately, even if no signs of any problems have appeared. If your dog has eaten xylitol, the first sign is probably hypoglycemia, but not necessarily. There is evidence that even if no signs of hypoglycemia were present in dogs that they still might be going through liver failure. Hypoglycemia symptoms usually take 30 to 60 minutes to appear and include but are not limited to lethargy, collapse and/or seizure.
Make sure that you check with your vet or dog nutritionists before using any recipe and make sure to list any ingredients you plan to use just to make sure that you do not inadvertently give your dog anything that is harmful to your dog. You want to make sure your dog lives a long and happy life.