Dun- I have run into this with the mineral thing. Also, the vet was telling me he had a run recently of several dogs that were unthrifty and just generally falling apart. Some were apparently starving,even though the owners were feeding them free choice. Turned out all of them were being fed the same brand of discount store dog food. The label looked OK,but when he sent it to be analyzed,it was made of things the dog could not convert. It was all going out the back,not much left for them to live on.