You can call or email the schools themselves and ask the admissions staff, but I bet they won't mind. The LORs will detail how you performed in your classes and whether the professors think you're cut out for medical/professional school. That's all the Podiatry schools will want to know. Science is science and medicine is medicine, wherever you go...unless you're going to some alt med quack...hehehe
Besides that, there are a lot of students who switch from the MD/DO route to DPM and probably also had LORs geared towards MD or DO. You're certainly not the first. The schools will understand.