NaeNae, this is Kelly's article:
Tinned Food - Shortening Your Pet's Life Span...
You could also look up Raw Meaty Bones. I think that link is at the bottom of the article.

Basically, the gist is, that dogs are carnivores, not omnivores like us. Hence a dog's diet should be mainly raw meaty bones (or whole caecasses), some offal, some whole fish, few table scraps. No dry food, no cooked food.
This makes sense to me and I have heard lots of people report that their dogs have really improved, especially when it comes to skin and coat. Ours seems to have some skin/allergy issues, so I thought it was worth giving it a try.

I have always included raw bones but I have since cut out the "typical dog food".
I do give him fish, too. And in the hope that it will help with his skin, he gets a cod liver oil capsule once a day (if I remember). The vet actually suggested this.

By the way, I don't give him apple cores. They can be toxic to dogs. If my kids don't finish their apples, I cut out the core and give the rest of the apple to Buddy (the lab). He loves them.