Yes Doctor. My Sister Is 48, A Smoker, And In

Yes Doctor. My sister is 48, a smoker, and in generally good health. When she eats butter on toast, in a baked potato, placed on the food and not necessarily when it is cooked in the food..., She is the following: sick to her stomach, vomiting on occasion, but a general sense of queasiness. Is this a sign of something besides a food allergy?
She seems to have the same reaction to cereal fillers in hot dogs, bologna, and some other meats. She does the same with bacon, and most pork, although not pork chops or ham.
I was hoping you could help me help her.