There is some information that Aspartame (Nutrasweet) can raise the INR. I haven't found a really solid website that discusses it, like the FDA site. But there was enough out there to make me wonder. What I have read is causing me to rethink what beverages I serve like Crystal Light, diet sodas, etc.
If anyone out there has the Coumadin Cookbook, maybe there would be something in there.
**This isn't a food, but I also came across information that taking several Tylenol during a week could raise the INR significantly.