Great question and I have no answer.
I can tell you that some supplements contain an ingredient called "stearic acid". This can come from beef. Ellie is allergic to beef. I was talking to the vet about it and she said it is always possible that there could be a reaction. Then again, I think I had read somewhere before about dogs not reacting to the fat, only the meat. I'd think the only way you will get an accurate answer is to try it...